Saturday, October 19, 2013

"I'm not a female scientist, I'm a scientist, man."

Middle schoolers from Oakland, CA tell a rap-battle version of the story of Rosalind Franklin, an x-ray crystallographer who made important contributions on the discovery of the DNA double-helix structure.

Wednesday, September 4, 2013

Mass flow controllers and finding one's path

I went to school for eleventy billion years and ended up with a bachelors, masters and Ph.D in electrical engineering (EE). I often wondered along the way if I should have switched majors at some point.

It probably happens to everyone, but as an undergrad I took a lot of required classes I wasn't really into. I discovered I was much more interested in learning how the individual semiconductor components worked and were fabricated than designing circuits that used them, or analyzing signals that controlled them.

NMOS and PMOS logic circuits were kind of interesting... but how they were made and worked at the fundamental level was WAY more interesting.

The nice thing about graduate school is you can delve into whatever little niche that interests you. For my PhD work, I specialized in metal-organic chemical vapor deposition (MOCVD) in the fabrication of laser diodes on nonpolar crystal orientation of GaN. This incorporated a little EE, and a lot of materials, chemistry, and solid state physics. It was a great way for me to steer away from my circuits-heavy background towards the fundamental physics and fabrication of electronic devices.

And yes, telling people I made lasers was so cool.

MOCVD, also called metal-organic vapour phase epitaxy (MOVPE), is a deposition technique for thin films and semiconductors. It's a big machine that involves metal-containing molecules called precursors which are routed through various gas lines to a reaction chamber where the sample, called a substrate, sits at high temperature. The precursors combine with other process gasses in the chamber and, over time, atomic layers of semiconductor material get deposited on the surface. This layer-by-layer deposition, shown below, is also referred crystal growth or crystal epitaxy.

In short, MOCVD is both the gigantic tool and the process I used to "grow" lasers.

Horizontal gas-flow MOCVD system showing growth of Gallium Arsenide.  The precursor chemicals containing Ga and As flow into the chamber and react on the surface of a hot substrate, leaving behind Ga and As atoms to incorporate into the perfectly crystalline film, while the rest of the precursor leaves through the exhaust.  Growth entails a continuous flow of precursors for a specified amount of time, depending on the rate of deposition and how thick you wanted the layer to be.

To "grow" an electronic device you first define all the layers in the structure you want, then you write recipes on a computer that controls the the MOCVD system specifying which precursor chemicals to use, when to turn them on, and how much of them should flow into the chamber at a given time. Each layer gets a little of this and a little of that and the amounts of each are finely calibrated.

Schematic diagram of a MOCVD system with two process gasses (hydrogen and nitrogen) and six precursors, with individual valves and mass flow controllers that control what and when to flow into the reactor. 

When you work in deposition equipment like I do, you get really familiar with mass flow controllers or MFCs. These small but necessary instruments are used to control how much process gas or precursor flows through the lines to the reactor. As a recipe writer and tool operator, one of the parameters you specify is the flow rate of each precursor through their respective MFC and when to turn them on or off. They direct traffic so to speak.

Relationship between velocity (v_bar) and flow rate, Q which is measured in units standard cubic centimeters per minute, sccm (pronounced "skim") or standard liters per minute, slm (pronounced "slim"). 

Just like I loved learning about the inner-workings of electronic devices as an undergrad, I love learning about the inner workings of the pieces of equipment used to make them. MFCs are a tiny part of a giant deposition system like MOCVD, but alone they are pretty interesting.

Here's a cool video from Sierra Instruments that discusses how MFCs actually do their thing.

Isn't that neat? They even use MFCs to make beer! Yay, beer!

In my new job, I'm basically a recipe writer and tool operator for a similar CVD-type system. My group specializes in the deposition of thin film dielectrics, which is used as a single layer in semiconductor devices. MFCs are still really important.

I'm still learning a lot and getting used to the fast-pace of industry work. Most of my coworkers come from backgrounds in chemistry, physics, and materials science. My EE background sets me apart in some ways and sometimes I worry I lack enough relevant background and have some catching up to do in that regard. Whenever I feel especially stupid, I remind myself: I have a Ph.D. in engineering. I'm not stupid. I should be able to figure it out. 

Hopefully, one day my knowledge of undergraduate level circuits will be an advantage... Perhaps in meetings with customers when they mention gates or FETs and I know exactly what they're talking about?  Honestly I have no idea. I may have a Ph.D. in engineering and a long term full time job that I like, but I still don't know what I want to be when I grow up.

So far, though, every path I take seems to lead me in the right direction.

The many paths of electrical charge and Kirchoff's current law.

Tuesday, August 6, 2013

Music that got me through college - Part 2

This is an understatement for those who know me well, but I was in college for a long time. I started attending community college at 18 years old, bounced around two undergrad universities, then endured a long stint in graduate school before finally finishing my Ph.D just after my 33rd birthday.

Another understatement: I love music. A LOT. Music has been a constant companion of mine and certain bands, songs and albums will always remind me of particular times in my life. And not in a general "this song reminds me of 1999" way but specific moments like "this song reminds me of moving into my first apartment" way.

I intended to make a whole series of posts about the music I listened to in the 15 years I spent in college. I posted Part 1 almost a year ago, which highlighted those early years in community college.

I am going way out of chronological order and skipping to the end: music that reminds me of writing the dissertation. I'll fill in the gap years in a future post, including my Skinny Puppy phase, and those handful of years being involved with the campus radio station.

Part 2. Dissertation writing (Early 2012)
Memories of drinking coffee, writing writing writing, crying, eating, watching some cat videos, writing writing writing, sleep, repeat.

Explosions In The Sky "Your Hand In Mine"

Band of Horses "The Funeral"

Grimes "Oblivion"

M.I.A. "Bad Girls"

Sunday, August 4, 2013

My life (so far) with semiconductors

and why I love dressing like a marshmallow.

I recently left the ivory tower of academia and got a job in the "real world" of semiconductor fabrication, where I spend a large part of my workday shuffling 300 mm silicon wafers around in a class 100 cleanroom, aka "the lab."

There's a very specific set of training and procedures to be allowed into the lab. In the hallway there is a dispenser of plastic shoe covers to put on, and then you must unlock the door with a keycard to enter the gowning room. This is where you don the required hairnet, jumpsuit, hood, face mask, another pair of shoe covers, eye glasses and gloves. Then you must pass through an "air shower" before finally entering the cleanroom.

The idea isn't so much to protect you from anything in the cleanroom, it's to protect the things in cleanroom from dust and from YOU.

This video shows a typical gowning procedure.

I'm not new to cleanrooms. I spent a large part of my dissertation work in the UCSB Nanofabrication Facility, which had similar gowning procedures I use now. I know you can never be in too much of a hurry to either enter or exit the lab as all the gowning and degowning takes some time.

I actually love having to wear a cleanroom suit. This might sound really strange but there's a few good reasons.

First, the act of getting ready to enter the lab is very ritualistic, which helps put me in the mental space to be productive and do work. Those 30 seconds of standing in the air shower with loud jets of cool air blasting at me from all directions are spent thinking about what I'm going to tackle first.

The other reason I like wearing a cleanroom suit is this: Especially as a woman in a VERY male-dominated industry, wearing a cleanroom suit makes me forget what I look like. When I'm in the suit, it doesn't matter. I'm not self-conscious at all. Even my gender is irrelevant. This is huge.

It's not so much that I'm particularly uncomfortable outside the cleanroom. I'm sure I stand-out since there are only a small handful of women who work on my floor of the building, but no one treats me any differently and with a Ph.D. in engineering I'm certainly used to being a minority. Still, there's something so comforting to me about being dressed like an asexual marshmallow. I noticed this in my graduate school work as well, that wearing a cleanroom suit removes any potential for awkwardness when working closely with male coworkers. Even if it's perceived potential for awkwardness on my end. In the cleanroom, I'm at ease. I feel more like an equal because we all look exactly the same.

Of course, the big drawback of everyone looking the same is it can be difficult to tell who's who. The only exposed part of anyone's face is a few square inches of space around their eyes, so you have to get pretty close to someone and look at them dead-on to recognize them. Eventually, you learn to identify your friends and coworkers by how tall and wide they are, or how they walk and carry themselves.

Also, if you meet someone for the first time in the cleanroom, you will need to be reintroduced outside the cleanroom because you will NOT be able to recognize them. At least once I've ran into someone in the gowning room and they told me, "Oh! KK! I had no idea that's what you looked like!" I'm unsure if this was a compliment.

Because of this, it's funny to imagine people who work in a cleanroom having romantic feelings towards someone they work alongside yet don't know what they really look like. Like in this Postal Service video (below).

For fun, I recently started a Tumblr called Cleanroom Missed Connections that explores this idea some more.

Friday, July 5, 2013

Teamwork in Grad School: Don't take it personal. It's only science.

Grad school is not a solitary endeavor.  

I should restate that as: grad school shouldn't be a solitary endeavor.

As a grad student with a research project you'll probably spend the majority of your time working within a larger group of researchers which may include your PI, defense committee, postdocs, project scientists, other grad students, internal collaborators, external collaborators, and so on. Your dissertation eventually gets defined as one piece of a larger puzzle that the group, as a whole, is trying to solve.

Of course the ultimate goal of grad school is to write and defend a dissertation. That, my friend, is inherently your own. Eventually you will break away from the group and focus on your own thing, especially during those last several months of frenzied last-minute experiments and late night dissertation writing as you race to finish.

You stand alone at the end, sure.

Until then, it's wise to think of yourself as a member of a team.

"There is no 'I' in team, but there is an 'I' in pie. And there's an 'I' in meat pie..."

Teamwork I should've learned in kindergarten but graduate-level research actually forced it into use. Some of us driven, left-brained, competitive, introverted types (I'm talking about myself here!) aren't necessary highly skilled at working well within a team by the time they start grad school, yet it's vital to survive in academic research.

A few things I've learned:

Treat grad school like a job.
This is basically impossible because your life is defined as a graduate student. And, often, the only people you see every day are other academics and graduate students. It can get pretty competitive as well as incestuous.

For me, it helped a lot to consider my research project as my "job" and my labmates as "coworkers." There's just something about that mental classification of calling trips to campus as "going into work" that helped me maintain some life/work separation.  Calling the other students in the lab "coworkers" helped keep interactions with my peers as professional as possible.  (Except when I happened to date them, haha.)

Being friendly and being friends are two different things. 
It may be unavoidable, but you don't have to socialize with your coworkers outside of work. You don't even have to like them. But you should be friendly with them anyway.

I was in grad school for over a year before I joined a research group. A HUGE research group. At the time, I only talked to a few senior grad students who were directly responsible for training me in the lab and didn't set out to specifically make friends with my extended research group. I'm pretty reserved by nature anyway, so I basically ignored them completely.

Looking back, my first few years could have been a lot easier and productive if I'd communicated more with my other group members right off the bat. Not only to broaden my social circle, but for collegiality sake.

Here's why:

Being on a first name basis with everyone in your extended group makes you a more useful member of the team.
It's important to be comfortable working alongside different people, even ones you don't work with very often, or don't seem to have much in common with, or wouldn't want to be friends with. Just knowing who's who and their area of specialty is a huge step. Going beyond that, to the point you actually say hello to each other when you pass them in the hallway, can be even better.

It's important to break down potential communication barriers because your coworkers and labmates can be valuable resources.

Experimental research work has so many unexpected twists and turns, you never know who might have an impact. 
Obviously, the point of a PI, defense committee, and group meetings are to share your results and ideas and get feedback in a structured format. Yet the more people you're comfortable approaching and engaging in unstructured, casual conversation, especially the ones working in the same office or lab, the easier it is to go to them with questions or problems. Even small ones.

Short, casual conversations at the right time can be more beneficial than a planned project meeting.

It's vital to facilitate these small conversations. 
Check-in with your group members, even the ones you don't regularly work with.  Someone with a slightly different perspective may end up providing useful insight.  They may ask an intriguing question, suggest a new idea, or interpret your results in an enlightening way. Perhaps they know the exact solution to the weird problem you're having, or read an esoteric research paper that's totally relevant with what you're trying to do, or are trained in some characterization tool that does the exact measurement you need to do.

I can't even count the number of times I struggled to solve some problem in lab, only to find out some other grad student figured out a much easier way long before. I only had to ask around.

Speak up if something goes wrong.
Thanks to Doc Becca for reminding me of this advice: If you make a mistake, say something! It's ALWAYS better to say something. Even if it's a little thing. But ESPECIALLY if it's a big thing. Making a mistake and hiding it are grounds for getting kicked out of a research group. I've seen it happen!

Mistakes happen all the time, it's fine, it's expected. But hiding them or not being forthcoming when they happen can only cause more problems. Coming forward and admitting mistake might be embarrassing, but it's fine. After all the point of academic research is to learn!

Asking for help is not a sign of weakness.
Graduate-level coursework and research are hard enough as it is. You can make it much easier on yourself, and complete tasks in a more efficient way, if you ask for help when you need it. Especially in terms of experimental research, operating equipment and analyzing data, asking for help is not an admission of failure.

Asking for help is what smart people do when they realize there's probably a better way.

In my research group, grad students work VERY independently and the ones who burn-out are the ones who take on the entire the burden of their project by themselves and get stuck. Sure, high-level technical details and mind-numbing measurements are part of the grad school experience and science in general, in moderation. But it's only useful if it's getting you closer to the goal.  And NOT at the price of your sanity. If you're getting nowhere, it's time to reach out.

Sometimes admitting difficulty (i.e. complaining, when done correctly, i.e. you tried a lot of things and none of them are working) turns into a really useful collaboration.

The whole benefit of working in a team is the ability to collaborate. 
Of course you should be expected to do a lot on your own. But you should also take advantage of the people around you, especially the more experienced grad students and postdocs.  If you're stuck on something, ask them how they would do it.  If you're having a hard time writing a paper, ask them to look it over and provide suggestions. If you're swamped, consider delegating some tasks to someone else.  Train a new student to take measurements for you.

If no one around you is being helpful, ask your PI to suggest someone new to talk to.

Give credit where credit is due.
Don't take advantage of people who help you. Acknowledge them. In fact, you may be ethically obligated to do so.

If someone contributed significantly on a project you're trying to publish, include their name in the author list or thank them in an acknowledgement section. If you borrow a slide or a figure that someone else made, give them credit by listing their name in the author list or put "courtesy their name" in the caption. When in doubt on how much specific credit you should give, ask. 

Offer to help.
Getting help when you need it is a benefit of working in a team, but this works both ways. Someone may come to you with a problem or question that's in your area of expertise, and it's in your best interest as a group member to try and help them out. If you can't help directly the very least you can do is politely point them in the right direction.

It's good to build up karma when you can because you never know when you'll help in the future. Who knows, helping someone else could lead to something interesting (or even a co-authorship). Of course, there is a line between being helpful and being a doormat, so it's important to know your limits, especially if it distracts you from making progress on your own research project.

Be approachable & agreeable (even if it's annoying).
As a postdoc and one of the most senior people in my research group, I had to do a lot of favors: giving lab tours to campus visitors, editing research paper drafts, training grad students, etc. I don't mind it all because I consider it part of my duties as a postdoc and I get a sense of fulfillment being able to help.

But it isn't always easy.

For example, I used to find it unnerving when younger students drop by my office unannounced asking for advice.  But I know being approachable is an important part of managing a team, and if the situation were reversed, I'd hope they'd be happy to talk to me as well. It's all part of fostering a friendly workplace. So I'd try to be open to it.

Email people back. But keep it prompt and short and sweet.
Email is my favorite form of communication with my group members. I know not everyone likes email, but it's a good way to keep a record of communication and progress.  So it's important to stay on top of it. Automatically filtering my inbox is a big help.

One of my pet peeves is asking for a quick favor or verification via email and not getting a reply, especially arranging meeting times with younger students. Sometimes IM/calling/texting is better if you need a reply within several hours.

Another pet peeve is receiving really long, rambly emails (although I am TOTALLY guilty of writing them). Sometimes it's better to schedule a face-to-face meeting if it requires more than a few sentences.

...And don't write angry emails. 
The worst interpersonal conflicts I've had as a grad student (not that there were many) was someone berating me with a really passive-aggressive, angrily-written email.  Usually it was for something completely mundane like misplaced lab supplies. DO NOT DO THIS. It's childish and unprofessional.

First of all, always give people the benefit of the doubt. If shit goes down and you're upset, give yourself time to cool down before you want to rage on your keyboard. If you're past the rage and still have a major problem, talk to them in person. You will find a much nicer way to phrase it when you're looking at them right in the face. If you can't do that, talk to your PI about it.

One of the important parts of teamwork and fostering a friendly workplace is civility. If someone made a mistake and you need to let them know, choose your words and language in a way that doesn't come across as angry or belittling.  We've ALL made mistakes. You don't want people to be afraid of admitting them.

It's okay to dislike someone you work with.
The Harvard Business Review has another great post How To Work With Someone You Hate that includes some helpful advice about managing your own reactions and keeping negative feelings to yourself.

There are some people I get along with really well, and some people I don't. I find it very emotionally draining to be around people I don't communicate with well, so I try really hard to managing my mood when I'm around them. Mostly I try to keep my personal feelings to myself and just focus on the task at hand.

Although, honestly, sometimes the easiest way to be around someone you don't like is to just be really nice to them anyway. It makes the time pass more quickly. And besides, just because someone's an asshole one time doesn't mean they're an asshole 100% of the time. If someone did something to upset you, give yourself some space, but don't hold it against them for life.

Don't badmouth coworkers behind their back (especially with other coworkers).
Try not to participate in office gossip. This is basically impossible in a grad school setting, but try. A little light-hearted ribbing is one thing, but often gossip can become cruel and unfair and create strife within a research group. Try to avoid it. This isn't middle school. Don't be a dick.

Besides, you never know who you might have to work with or depend on in the future, so it's better not to burn that bridge.

If you MUST gossip, do what I do and make up funny nicknames about your coworkers so you can vent about them to your non-grad student friends.  (You still have non grad school friends, right?)

Diversity leads to more innovation. But it can also bring conflict. This isn't necessarily a bad thing.
And by diversity, I don't just mean ethnic or gender diversity. (They are both great, for sure!)  I mean diversity in a larger sense. David Goldberg wrote a good article about different kinds of diversity, such as diversity in personalities and aspirations, and how they can inspire innovation. Which I totally agree with. More diversity is better all around.

BUT the downside of having many people with many differences in ideas and points of view and opinions is it CAN lead to conflicts.

Conflicts are not a bad thing. In fact, the Harvard Business Review suggests that conflict among team members can often lead to more creative outcomes.

It comes down to respect. Differences in opinion are great if they are appreciated equally. Again, don't be a dick. Be patient. It may take longer to resolve things, but the solutions will be all the better for it.

Realize everyone communicates differently.
I get uneasy categorizing other humans into "types," however, I recently attended a seminar on communication that talked about the Hermann Brain Dominance Model that breaks up people into four types: Analytical, Sequential, Interpersonal and Imaginative.
  • Analytical thinkers are logic and fact driven and want to know how things work. They're the ones arguing about data in a group meeting.  
  • Sequential thinkers are detailed, organized and like to break things down into steps. They're the ones typing out step-by-step instructions for lab equipment. 
  • Interpersonal thinkers are more sensory and feeling and like group discussions. They're the ones organizing the group happy hour.  
  • Imaginative thinkers are more conceptual and like to look at the "big picture," can be innovative and solve things long term, but gloss over details.  
For example, I'm a "sequential thinker," and it's important to me to take very detailed, careful notes whenever I get trained on new equipment. Other people don't like taking notes  and would rather just watch and listen. I used to think this was irresponsible, but I realize now that it's just a different way of learning. Which is totally fine.

It's not particularly important to have a list of types, or what they're called or how many types there are.  The point is this: it's important to recognize and respect the fact that someone may operate differently from you. This recognition and respect will make working with them easier.

Communication is what real science is all about. 
Grad school can be a bubble. Don't get trapped in a bubble. Not many people can be successful being in a bubble.

The whole point of doing science is communicating your results: writing and reading research papers, attending conferences, and so forth. It's not just about designing experiments and getting good results and then graduating and never being heard from again.  If you can't communicate your science, you're kind of just wasting resources.

Oh yeah, and there's that networking thing, too.
One day you WILL graduate, and being on good terms with as many people as you can may be beneficial for your future career endeavors. Trust me on this. You will need to look for a job one day and you'll want to reach out to as many people as possible.

Consider the fact that people you don't know very well can be more helpful than your closest friends, career-wise.  Adam Grant wrote about the hidden value of "weak ties." He says, "When you haven’t seen people in three or five years, you can’t predict what novel ideas and networks they’ll be able to share. And it turns out that the older you get, the more valuable dormant ties become." This is what networking IS and this is why social networking sites CAN be useful.

Don't take it personal. It's only science. 
Sometimes there are disagreements. Sometimes you get cut out of a project, or all your friends got to go to some conference and you didn't, or someone undeserving gets a great result while you're slaving away getting nowhere, or someone lands a better job out of school than you did. Sometimes people are just assholes. It's important to not let these kinds of things get to you.

Some might say 'pick your battles' but I'd rather say 'suck it up and get back to work.'

Your coworkers are not your enemy. You are, after all, part of a team.  


Check out my Grad School Survival Guide!

Wednesday, July 3, 2013

Clearing out my desk

This is me cleaning the desk area where I spent the past six years as a grad student and postdoc:

#DGAF #later

(That's not entirely true.  I still give a little bit of a fuck.)

Friday, June 14, 2013

Leveling Up

I got my first big girl job!
After being in school for what seems like eleventy million years, I'm moving to Portland, Oregon in a few weeks to start a new life as a process engineer for a semiconductor equipment company.  Whoo!

I'm a little sad to be leaving California, my friends, research group, and academia in general, but it felt time for me to move on and I'm excited to do something different.

I'll be working on thin film deposition.  Which probably doesn't sound exciting at all to most people, but that's okay.  (As long as it does to me, right?)

While we're on the topic of thin films, here's a cute video (meant for kids?) from Filmetrics that explains how spectral reflectance works for measuring film thickness.  This basically entails shining light of different wavelengths (colors) at the film and seeing which wavelengths (colors) reflect.  If you know the material properties like refractive index, then you can make a pretty good estimation of how thick it is.

I won't be a postdoc working with lasers anymore, but will continue to update this blog and likely post more about microelectronics and my experience transitioning to life in industry.  Plus, I still have plenty of advice for grad students left to write. In fact, I have some upcoming posts about teamwork in grad school and conference etiquette, so stay tuned for those.

Tuesday, June 4, 2013

Pro tip: don't be a dick

Teamwork is a really important skill in graduate school and life. I've been working on a long blog post with about working well with others, which I will post one day. One of my tips is this: Don't be a judgmental asshole.

UNM Professor Geoffrey Miller tweeted this gem a few days ago:

This is a great example of a comment that makes someone sound like judgmental asshole. This kind of comment has NO PLACE in public forum ESPECIALLY from a professor who has the power to fire and hire potential PhD students. He eventually deleted the tweet and apologized for his comments, but only after a strong backlash. (You can read more details on the controversy over at The Atlantic.)

We all have coworkers who say stupid things. I'm actually the queen of sticking my foot in my mouth, so I'm guilty of it as well on occasion. Still, I try to be really careful about how off-hand remarks are perceived in a professional setting, especially now that I'm a postdoc and grad students might look to me to lead by example.

A good rule of thumb is just don't be a dick or an asshole. Period. Just don't do it. If you catch yourself doing or saying something that comes across poorly, own up to it apologize. Then next time, maybe you'll think twice before you open your big stupid mouth.

The bottom line is that all people deserve to be treated with respect. Especially in academia, be especially kind and encouraging to those who come in a shape or size or color that is not already well-represented in your field. Diversity in STEM and higher academia in general is so, so important for inspiring creativity and innovation.

Check out the awesome new Tumblr: Fuck Yeah! Fat PhDs.

And while we're at it, can we cut it out with the carb-shaming already?

Monday, May 20, 2013

Elevator pitches & LEDs

Watch Cyrus Dreyer, a graduate student in Chris Van de Walle's Computational Materials group at UCSB (and one of my coworkers), give an elevator pitch on LED research for general lighting applications. It's title: "Lighting the World from the Head of a Pin."

Obviously, he's glossing over many technical details on how LEDs work, which is so hard to do because investigating the technical details is what we DO everyday.

In an elevator pitch, the point isn't to communicate details.  The point is to communicate broader context, significance, and something memorable that sets your technology apart.  For LEDs, one thing that sets them apart is the super small scale of the light emitting layer which is only a few nanometers thick.  One billionth of a meter.  That's approaching the scale of individual molecules.

Fun fact: your fingernails grow about a nanometer a second, which is actually faster than the rate we "grow" the light emitting layers for our LEDs. But that's another story for another time!

Cyrus Dreyer's presentation was part of a Grand Slam contest organized by UCSB's Grad Post.  You can see the other finalists and winner on Youtubes.

Friday, May 3, 2013

Communicating with visible light

The quick brown fox jumps over the lazy dog. 
There are 26 characters in the English language and that sentence uses every one.

The digital world uses two characters: 1 and 0. My fingers press buttons on a keyboard and it's translated into the language computers speak: on and off, go and stop. Electrons shift in a strip of metal.

But it doesn't end there.

Communication over distances takes many forms. A lot happens to those 1's and 0's before becoming letters and words again wherever you are. A laser shining into a fiber of glass, and then a tiny transmitter emitting energy right into the air.

Isn't that amazing?

Data is all around you.
Energies of particular frequencies can travel easily through the atmosphere. This is the radio frequency band, which spans kHz to GHz range.

In wavelength, the radio band spans waves a millimeter to a full kilometer long, peak to peak. That's long enough to easily travel through walls too.

Humans discovered long ago how to generate and manipulate or 'modulate' radio waves to carry information. Amplitude modulation (AM) or frequency modulation (FM) are a few examples.


These days, there is a LOT of data in the radio frequency band besides AM and FM radio, including broadcast tv, cell phones, bluetooth, and satellite communication. It's all carefully allocated and regulated by the FCC. (Check out this awesome chart.) 

But some say the radio frequency is getting crowded

They say there's another option. 

They say we can transmit data using a different frequency range. And it happens to correspond to wavelengths your human eyeballs perceive as LIGHT. 

And we can use LEDs they said. And we can call it Li-Fi they said.
In his TED talk on Visible Light Communication, Professor Harald Haas coined the term Li-Fi. It's like Wi-Fi but it uses visible light from an LED to transmit data. 

Because LEDs are made of semiconductors, the stuff computers are made of, they can be easily modulated to transmit data through the air. 

You could think of it like a strobe light spelling out words in Morse code, only really fast. Fortunately the human eye is slow, so a light flashing on and off faster than 60 times a second looks the same as "on."

The only problem with Li-Fi is it can't go long distance and can't go through walls. Because physics. But for research funding reasons, you could easily call it a security feature, not a limitation.  :)

LEDs are awesome, yet again. 

More info:

Tuesday, April 23, 2013

Sunday, April 21, 2013

Lasers + music 4EVA

From Dennis P. Paul, "An Instrument for the Sonification of Everday Things." It makes sounds out of random everyday objects. USING A LASER. 

Other people have figured out ways to make music with lasers.

Such as a laser harp.

Or whatever the hell this is.

This is a song made with a laser engraver. (I don't think the laser is even turned on.)

Laser engraver plays Super Mario theme from Jedediah Smith on Vimeo.

Lasers have influenced music in lots of ways.

Here's Queen singing about lasers back in the seventies when lasers were the rage. OK, they merely mention lasers. But it's QUEEN.

Lasers have remained popular throughout the years.

Major Lazer named himself after lasers.

The Flaming Lips incorporate lasers in their live shows.

An authentic laser light show is a great example of music and lasers combining into an art-form onto itself.

I've actually never been to a laser light show but I hope to convince someone to go with me one day.

Yes, I am still a 34-year-old woman.

This post is silly. Life is short.

Monday, March 25, 2013

This is what a scientist looks like (but not really)

University of California Television (UCTV) recently put together a four-part video series on one of my dissertation committee members, Prof. Shuji Nakamura, and his role in GaN-based light emitting diode (LED) research. It's a great overview of the history of GaN and the impact it's had on energy efficient lighting applications. You can watch them online here.

The videos include several shots of our labs at the Solid State Lighting and Energy Center at UC Santa Barbara. Part 2 of the series talks about Nakamura's early life and his persistant motivation trying to create the worlds first blue LED on GaN. It also includes a shot of me at the 7 minute mark, just as the narrator explains how difficult it was to work on this semiconductor material.

Here I am, looking like a movie scientist:

You can tell I'm a scientist because I'm wearing a lab coat and looking through a microscope. That's what scientists do. [deadpan stare]

A similar shot of me shows up again in Part 4 of the series, just as my PI Prof. Steve DenBaars is discussing lighting applications based on laser diodes. Here I am again looking a bit more hunchbacked, staring into that same microscope:

At my laser:

Perhaps needless to say, these shots were totally staged.

Most of my friends and family have no idea what I do for a living. Although the entire video series explains my research and the research of my group in general terms very well, this brief glimpse of my lab isn't particularly enlightening. Obviously what looks good on film is often not true to life.

In a small manner of communicating my science to the masses, I'd like to point out what parts of these few seconds of me at work is actually authentic.


  • This is the actual lab and test set-up I used to test laser diodes for my dissertation work. 
  • The microscope I'm looking through is the one we use to align the needle probes onto the laser diode devices, which we need to do because they are so tiny.
  • During filming, I had an actual laser diode probed and turned on via a pulsed wave generator, one of the tools located on the shadowy lab bench, at eye-level, which is connected to the probe station via a nest of coax cables. 

  • In the beginning of the shot in Part 2, I'm actually adjusting the seconds per division on the digital oscilloscope, which is totally unnecessary to adjust since our measurements are automatically calibrated and measured via a Labview program from a nearby PC.  However, at the time I had things in manual mode, and the scope was actually displaying the light output, current and voltage across the device I had probed.
  • I displayed a blue laser beam pattern on the computer monitor in the background. This is an actual image from one of my laser diodes, just not the one currently probed.  
  • In the close-up of the actual edge-emitting laser diode I was "testing," I had the current and duty-cycle turned way down, to make the light very dim. Otherwise it would look too bright for the camera. With the current that low, it wasn't even "lasing," just a faintly glowing stripe of light. 

  • The gel lights. Unfortunately ubiquitous in any fictionalized science lab. Our lab has standard fluorescent lighting, but obviously that doesn't look dramatic enough. I laughed when the film crew started setting up the green gels, which we joked was the "official color of science."
  • The lab coat. I normally don't wear one for laser testing. I actually wore a nice collared shirt and sweater the day we filmed this, but the camera guy really wanted me to wear a lab coat, so this is a random one I grabbed off the rack in the hallway that was WAY TOO BIG.
  • The video doesn't show all the other things I spend 95% of my time doing, such as: MOCVD crystal growth, cleanroom processing, materials characterization, plotting data, making powerpoint slides, and telling first year grad students what to do (haha).

In the end, I think my role in the video was mostly authentic and I'm happy with the way it turned out. I was glad to participate in the exercise, not only to show off my lazerz but also because I knew there wouldn't be very many females in the video otherwise. Which is the subject of a whole other post. Ladies.

I wrote about laser diodes, so go read that post if you want to know more.

Here's the rest of the UCTV video series:
  • Part 1 - The LED to improve education in the developing world.
  • Part 2 - Shuji Nakamura and development of the white LED
  • Part 3 - The breakthrough that creates the white-light emitting LED
  • Part 4 - Research into the future of lighting and energy use.

Thursday, February 28, 2013

Experiments with light.

This week I stumbled upon Veritasium, a video blog featuring experiments and explanations about various topics in science and nature. The host and creator Derek Muller, who has a Ph.D. in Engineering Physics, aims to communicate sometimes abstract scientific concepts to the public in an interactive and easy to understand way.

This is a GREAT video he put together demonstrating Thomas Young's double-slit experiment. When Young first presented his results of his experiments to the Royal Society of London in 1803, he explained: "...(it) may be repeated with great ease, whenever the sun shines, and without any other apparatus than is at hand to every one."

The property of light that this experiment so elegantly demonstrates is it's distinctly wave-like. It has properties of waves, such as a wavelength (or color) and it can constructively and destructively interfere with itself, like ripples in a pond.  In the early 1800's, this idea was very revolutionary, as it was commonly believed that light behaved more like individual particles, thanks to pioneering work by Isaac Newton in the 1600's.

Double slit experiment showing small particles, such as individual electrons or photons, passing through two slits will cause an interference pattern, a property of waves. Isn't that crazy? Yes. It is. Because quantum mechanics is totally bonkers, but that's why it's so interesting.

Turns out Young and Newton were both right. As Albert Einstein discovered 100 years later in the early 1900's, light can behave both like a wave and a particle, and this particle can only have only a discrete set of energies, or quantized energies.  Today, we call these discrete quanta of energies photons. Einstein's work describing the photoelectric effect -- in which you can shine light at a metal and get it to conduct electricity -- won him the Nobel prize in 1921.

The photoelectric effect: If you shine light, made up of photons of specific energies, at a metal material, the light will excite the electrons in the metal and cause them to eject from the surface.  The idea of photon-electron interaction is an important piece of the quantum mechanics puzzle. 

The so-called wave-particle duality is one of the main concepts of quantum mechanics and is essential in understanding how semiconductors and solid-state light emitters work. Of course, quantum mechanics gets very dense and abstract very quickly, and details of it are still being discovered to this day. Still, it's fascinating to think about how simple experiments like sunlight passing through a double-slit were so influential in developing our understanding of light and matter.

Saturday, February 23, 2013

Oh, the sometimes mindless drudgeries of experimental research

My research has taken on several interesting developments lately. As exciting as this is, the downside is it requires generating a lot of samples, and painstaking measurements on a lot of samples, which has been very time and energy consuming. On top of paper writing and all my other postdoctoral responsibilities, I'm swamped with work. I've recently recruited a graduate student to help me out on the measurement side, thankfully, as I'm not sure how I would manage otherwise.

As tough as it is, I know my project is (finally) building up to something interesting (and publishable). I remind myself that many scientific discoveries are likely not serendipitous eureka moments, but probably required a lot of planning, time and effort. And measurements. Long, slow, mind-numbingly boring measurements...

In experimental research, sometimes you can't avoid what feels like mindless drudgeries. This is why patience and dedication is such an important skill in graduate school. Also coffee. Also lab computers with internet access.

(Thank you, When In Academia)

Thursday, February 7, 2013

Productivity & email

One of my tips for grad school is to come up with a systematic way to stay organized and consistant. I'm not at ALL tidy or organized in real life, but at work I NEED a good system to keep my research and sanity in line.

Something I quickly learned to get under control as a grad student was my email. Between coworkers, campus-related announcements, department-related announcements, lab-related announcements, as well as personal emails, bacn, spam, etc., it can get overwhelming pretty quick.

Colleen Wainwright of Communicatrix changed my life when I saw this video on how to use the filters function of Gmail to automatically sort incoming mail. This is a few years old, but still super useful.

Show me yer rig! (Gmail filters edition) from communicatrix on Vimeo.

I now have all my email accounts get routed directly to my Gmail account which then auto-filters them into folders. The best part of this system is they are accessibly from anywhere, and if I go off-line for several hours or days, I don't have so many new messages in my inbox demanding attention when I return. Instead, I can easily find where the most important messages are, and then skim over the rest when I have time.

I also love Gmail's advanced search functions to quickly look up an old messages. For example, if I'm trying to find an old email I sent that had an attachment, I search "from:me has:attachement" and it will narrow down to find it easily.

I know Gmail isn't the only service that has these functions (and is likely not the best). Still, when I hear people use Gmail and don't auto-filter their incoming email, I'm just like: "WHAT?? HOW DO YOU LIVE??" And then I punch them in the face. 

The end.

Sunday, January 27, 2013

Disneyland and infrared communication

Last year, Disney unveiled new LED-enabled Mickey Mouse hats that interact with Disney California Adventure shows like World of Color, a feature they call Glow With the Show. Disney Creative Entertainment Technical Director, Chuck Davis explains in the video below.  p.s. Doesn't he seem to have the coolest job ever??

This video above was taken during a special closed viewing of the show for annual passholders to test out the hats, which they handed out for free. LUCKY!

The hats actually have a simple circuit inside, which you can read about in a teardown at the blog Stuff Andy Makes. Excuse me while I geek out a little about the components in this thing. There is a battery, switch, and a small Texas Instruments microcontroller which acts as the brain. Each ear is equipped with two RGB LEDs which can individually emit red, green or blue, or any combination of those three colors, including white.

Side-note: The RGB LED is actually just three individual LEDs packed into one package.  Here's a similar surface mount RGB LED in a 3.5 mm × 2.8 mm package with four pins: one for red, blue, green, and a common pin which can either be a common anode or cathode. Isn't it cute? You can see the little wire bonds connect to the common pin at the top right quadrant.

Four pin surface mount LED package, with three individual LEDs and a common pin.

The interesting aspect of the hats isn't so much the LEDs, it's the data synchronization. The hats 'interact' with shows in the park depending on where you're standing. Sounds magical, but it's actually possible through simple short-range IR communication, or in other words, at slightly longer wavelengths than visible by the human eye.

Note the x-axis is log scale here.  Most consumer IR products operate at wavelengths around 900 - 950 nm.

For the World of Color shows, the audience viewing area is divided into 40 different zones, and IR transmitters located throughout (on speaker towers perhaps) that transmit different data signals. The signals are 'seen' by an IR receiver located in one of the ears of the hat. As Chuck explained above, it's the same way remote controls wirelessly transmit information to your TV. There may be some position triangulation using signal strengths of neighboring transmitters as well, but that's pure speculation.

IR transmitters are not new technology, they're often just a GaAs-based LED plus some lenses to control the transmission angle. Sometimes it's a laser diode. The receiver is a photodiode, which is basically an LED operated in reverse: shine a light at it, it generates a current, like solar cells. Here's a tiny surface mount IR receiver similar to the one in the LED hat, by Vishay.

You can buy reels of these tiny IR receivers at less than $0.60 a pop.

IR wavelengths fall just outside the visible spectrum so you can't see them, but the 'light' emitted from IR transmitters otherwise has the same properties of visible light. One of these properties or requirements is line-of-sight (LOS), meaning: if you're wearing an LED Mickey hat and you're standing behind a tree or your head is turned the wrong direction, your hat may not 'see' or 'receive' the transmitted signal. Line-of-sight of IR components are demonstrated nicely in this Youtube video.

Fun fact: Plenty of wireless communications, such as radio, also depend on line-of-sight which is why radio towers and repeaters are often placed on top of mountains.

Little dudes demonstrating Line-of-Sight with a radio transmitter/repeater 

Another fun fact: Fluorescent lighting (including compact fluorescents) can emit spurious light in the IR spectrum, and early adopters found their lightbulbs interfered with IR communications of their TV remotes, causing channels and volume to change spontaneously. The problem was eventually solved by altering the operating frequencies of the respective components, however, the simplest solution is to just move or shade the lamps to remove the line-of-sight.

According to Stuff Andy Makes, you CAN get the Disney LED hats to respond to your TV remote control, but doesn't say what it makes the ears do. Doesn't that make you want to get one and try??

Disney's Glow With The Show LED hats also have a tiny IR transmitters (just an IR LED) inside them in addition to the IR receiver. This feature allows you to synchronize the two hats only by bringing them in close proximity, as demonstrated by Erin of the Disney Parks blog. Neat, huh?

The Glow With The Show hats normally cost around $20 and are sold in some gift shops around Disneyland California Adventure. I'll be interested to see how Disney Imagineers integrate Glow With The Show features throughout the rest of the park. Actually, I had every intention of buying one when I was at Disneyland last weekend, but honestly I thought they're pretty ugly on their own... so I went with some Minnie Mouse ears instead. :P

Friday, January 25, 2013

Complex concepts with very simple vocabulary

The UpGoer5 meme has gone around the Twitter and science blogs lately, so I tried my hand at describing my LED and laser diode research using the 1000 most commonly used words

When something is really, really small --too small to even see-- it acts in very strange ways. This is my work. I study really, really small things and get them to light up. This is a totally new way to make light. My lights are smaller, last longer, and don't get hot when you use them, so we can do many interesting things that we couldn't do with the old way of making light. For my job, not only must I understand how these very small things work and get them to light up, I also need to understand how our eyes see, and then I try lots of different things to make the light better and brighter. I hope that one day, the lights I work on will be used all over the world and am excited to see that start to happen.

It's an interesting exercise that reminds me a lot of trying to come up with an elevator pitch of my research project.  Because the vocabulary is so limited, I felt my description had to get really vague and big picture. For example, I could not come up with a way to describe a laser diode without using words like 'narrow' or even 'shape' or 'beam,' which were not included in the list, so I went with really generic description of solid state lighting "a new way to make light."

The UpGoer5 text editor by Theo Sanderson was inspired by this XKCD comic by Randall Munroe.

Check out Ten Hundred Words of Science for many more descriptions of research science using simple words.

Thursday, January 10, 2013

Overly Honest Methods

I'm so happy to see the hilarious #OverlyHonestMethods Twitter hashtag has gone viral, as evidenced by recent coverage by Huffington PostThe TelegraphScientific Americanio9, and Boing Boing.

Newsy Science points out the potential "troubling" side of being overly honest...

I understand the potential for controversy when questionable scientific practices verge on the side of being deceptive or otherwise demonstrate a lack of integrity. Yet I think more good than bad can come out of airing out some of the silly and honest aspects, albeit sarcastically, about how real science is done. If anything, it reminds us that scientists are humans too.  It's comforting to know that we all get lazy, take shortcuts or unintentionally make mistakes sometimes.

A perfect experiment is an impossibility, and part of being a good scientist and researcher is knowing how to identify and avoid, or at least acknowledge, all the messy complications and difficulties that come with experimental work.

Sunday, January 6, 2013

The importance of asking for help

The moment will be burned in my brain forever. It was like an anxiety dream come true. I was in third grade, my teacher just handed out an exam, and I was lost. I didn't understand the directions or how to even begin to answer. All the kids around me were working away, writing down answers while I just sat there staring at the blank page, completely frozen. I felt so helpless. I even whispered to the kid next to me if I could see his answers to which he hissed: "NO! THAT'S CHEATING!"  I started to cry.

Desperate, I stood up in the middle of the exam, tears still streaming down my face, and walked up to my teacher sitting quietly at her desk and asked for her help. She was actually very receptive to this and kindly reminded me what the exam was about and how I might answer. Whatever she said made it click. By the time I got to my desk, my tears had stopped. Perhaps I was even smiling. I had this under control. I GOT THIS.

There's value in admitting you don't know something. I think back over my grad school career and some of my biggest regrets are not asking for help sooner because I didn't want to let on that I was struggling or incapable. I wasted a lot of time being afraid of looking stupid and then feeling guilty about it. Is it arrogance? Impostor syndrome? Either way, it's so self-defeating.

Some of my tips for grad school include things like "prepare to feel stupid (again)" and fostering an environment that allows you to be productive as possible. Sometimes your ego is the only thing holding you back from being productive. 

The thing about scientific research is it will always seem full of more questions than answers. At the PhD level, everyone is so specialized that there's bound to be someone who knows more than you do about some particular aspect of your research project. Being a productive researcher involves knowing who to talk to in order to make progress. Don't think of it as an admission of personal failure, think of it as a collaboration. Often others are more than happy to help, and in fact, studies have even shown that most people underestimate how many people are willing to help even a perfect stranger.

It's a lesson I keep reminding myself. This past year, I kept putting off some measurements because it required being trained on an intimidating piece of lab equipment. It came down to me being afraid of asking for help from the tool manager who has a reputation of not returning emails or being particularly friendly. I finally got fed up with myself, asked for his help in person, and found he was more than willing to do so. Once I got through that first measurement I felt comfortable using the equipment on my own. Then I wondered, what on earth took me so long?

Friday, January 4, 2013

Dara O'Briain and Science Club

There are two things I love for sure: comedy and science. It's rare the two intersect, but when they do, amazing things happen.

Dara O'Briain studied mathematics and theoretical physics at University College of Dublin before embarking on a career in comedy.  I love this rant on the public perception of math and science and anti-science in the media, from his comedy special Talks Funny.

"Science knows it doesn't know everything, otherwise it would stop."

Dara currently hosts a television show Dara O Briain's Science Club on BBC Two. Each episode explores a different scientific topic in an informative, accessible, and humorous way.  I love it. I wish there were more shows like this on American television.

Episode 1 investigates human reproduction and genetics. I loved the bit about the invention of bicycles and personal transportation helping diversify the human gene pool.

More episodes may be available on Youtube, unless you're lucky enough to live in the UK and watch it on BBC.