It’s been a long time since I’ve written anything about my research here on this blog. Sure, I guess I’ve written about my research in exercise physiology a bit but I don’t think that really counts. Ever since I submitted my paper on 1D photonic crystal switching based on dye electrophoretic movement to Applied Physics Letters this past spring I’ve been working on building a 3D photonic crystal. So, that’s a lot of months! There’s recently been some good progress and I had some good success this past week. I’m not going to delve into the details because I’m essentially certain that of all the people who read this page aren’t checking up on the latest in photonic crystal research! I mention it so infrequently. But, a photonic crystal is a pretty beautiful thing on the macro-scale as well as on the nanoscale so I figured I’d post some pictures.

I guess all that’s clear is that the colour changes, which is indication that I at least did something right. The quantitative measurement of the optical properties however yields better indication that a bandgap exists, rather than just basing speculation on the presence of some shimmery looking stuff. A bandgap appears as a “bump” in a reflection spectrum and a “dip” in a transmission spectrum. The reflectance spectrum is shown here:

The nanostructure of the photonic crystal is created by seeding a surface with nucleation points and then depositing a structured thin film based on a 3D lattice structure which has a B-Zone that creates a complete bandgap. An example of how the seeding works is shown at left and then two images of a structured photonic crystal thin film are shown at right. (click the images to see them larger)

My paper was published in Applied Physics Letters on August 2, 2010.

Reflectivity of a photonic crystal device fabricated by glancing angle deposition may be reversibly
altered by infiltration with an absorbing dye solution. An electric field controls the dye ion motion
through the photonic crystal. Rapid reflectance changes up to 0.4 in the crystal’s optical band gap
are demonstrated. The time evolution of the dye movement process is examined and its operation
described. This work may have applications for a passive optical display. © 2010 American Institute
of Physics. doi:10.1063/1.3473827

The figures follow:

FIG. 1. (a) Bragg stack photonic crystal microstructure fabricated using GLAD. (b) Schematic representation of assembled cell, not to scale. Reflectance is measured from the top surface.

FIG. 2. (a) Reflectance ranges achieved when driving the cell with 800 mV. Negative polarity yields a reflectance minimum, whereas positive polarity drives dye out of the crystal for a reflectance maximum. (b) Maximal reflectance variation (λ = 715 nm) driven at three voltages. Same reflectance scale as left.

FIG. 3. (a) A reflectance time response of the cell at 715 nm when addressed with a driving voltage of 1000 mV. (b) The calculated characteristic time constants of the optical response. Driving voltages of 600 mV, 800 mV, and 1000 mV are shown in light, medium, and dark gray, respectively. Gray borders indicate wavelengths where rise or fall behavior resembled a clipped exponential.

If you’re interested in a copy of the .pdf of this paper and cannot download it from the internet you’re welcome to contact me and I will pass it along via email.

Convocation was Wednesday in Edmonton. I at first thought it was a pretty outrageous idea to travel all the way up the QEII highway just to walk across a stage and get 3 seconds of fame. Indeed it was as expected, three seconds of walking across a stage, but everything else was pretty good and I enjoyed it thoroughly. Dean Lynch bought all of the grads lunch and we has a chance to catch up with a few classmates. Then we did a few photos in the gowns and headed over to the Jubilee Auditorium for a few speeches and a parade across the stage.

I have to say that I thought the speeches were a ton better than expected, I wondered sometimes as an undergrad how out of touch the administration was with what actually went on on campus. While I’m probably still justified in thinking that to a certain extent what everyone had to say was particularly relevant to the occasion and as a whole rather well presented.

So as Dr. Zemp would say “I’m running out of things to say so let’s look at some pictures”

The Iron Ring ceremony for graduating engineers to be obligated into the profession was held this past weekend on March 29. The day started out with an ethics workshop put on by APEGGA in the morning, a rather excellent lunch and somewhat entertaining speaker (more for method of deliver than content) and then the ceremony. The ceremony is meant to be closed to the public so I’m not going to divulge details here. Anyhow, we all left with smiles on our faces:

We then cruised around downtown and went for dinner at the creperie. Following that a few EngPhys dealt with a robbery while the others proceeded to meet most of the addicts on Jasper. I was almost certain that my library book was stolen from the car and would have to pay a fine but the cops got it back. The evening wore on with a lengthly poker game and philosophical debate regarding whether or not it’s a valid system that we have created where the most effective means to getting good grades in your education are not the most conducive to learning material well.

We all decided that our education system has created test writing machines out of us, that we’re all very well adapted by this stage in our careers to demonstrating rapidly and with loose accuracy significant amounts information under relatively high stress conditions. In addition to the skills that were developed, we noted a few lacking areas contasting them. The retention level of such a situation is deemed to be low. This was attributed in part to the reality of gaining a grade at the end of a course and not being required to retain the information. Additionally however the examination style that follows the period of learning is one that doesn’t demand intimacy with the source material so long as it can be retrieved swiftly and with accuracy. Coming from the African education system Ayo suggested that his experience was even more that way and that in reality there was never any thinking required in the course of his secondary education. While the room was full of people who have successfully managed (very successfully, and in a few cases the most successfully) to develop skills to operate within the current education system, we unanimously identified that it was a bit scary. Upon departure from an academic institution the fact that regurgitation was smiled upon is not likely to benefit us in the long run. The ability to take in information at reproduce it in various forms does not aim careers favorably towards innovation and generally positive contribution to society.

Is there a cooling off period following graduation that is required so that we as humans can return a bit more towards mainstream life? I think so, but I’m also aware of the fact that the best way to reform bits and pieces of one’s mind is to stretch it a bit far in one direction and then let it slide back a ways, inevitably it will be shaped a bit by being drawn in that direction. I think to my own experience identifying myself on the political spectrum. Being drawn heavily in one direction under a certain experience can lead me a bit far afield, but allowing time to season that experience and come back to a bit more of a mainstream position leaves me with a better understanding of things and where I actually do find myself. Hopefully having been stretched over the course of the previous four years into a significant amount of information processing as well as priority management will shape a more efficient and balanced mind.

I finished the logo for the Engineering Physics summer clothing order 2007.

Piranha is a 3:1 mixture of sulphuric acid (H₂SO₄) and Hydrogen Peroxide (H₂O₂), used for cleaning organic deposits in the nanofab, the UofA’s microfabrication facility. It is also , of course, the name of a flesh eating fish found in the Amazon river basin. For more information or to order clothing check out this document.

Engineering Physics is having election this Thursday and Friday. I’m running in three races. Here are my campaign posters.

If you’re allowed to vote, visit the club sometime on Thursday or Friday. If you have any reason at all not to vote for me, maybe we should discuss things and I’ll convince you why I’m far more qualified to do this job and why I’ll do a much better job of it that the other candidates.

Elections for the Engineering Physics club take place next week, but it’s more of a round of “approvals” by any voters regarding the only volunteers for certain positions. I had planned on running for President but decided following a brief discussion with Ian that I wasn’t going to run against him for the position of President. I would rather see a club that functions properly than have the opportunity to be president for a year. Nominations are as follows:

• President: Ian Bushfield
• VP Academic: Steve Melenchuk
• VP Finance: Josh Krabbe
• Fourth Year Rep: Josh Krabbe
• Clothing Coordinator: Josh Krabbe
• Geer Week Coordinator: Ben Nearingburg
• Geer Week PR rep: I think I’ll volunteer for this job, I mean I did attend 15 out of 17 events this year

It’s looking like it should be a good year, success of the Phryge depends on Julian’s cooperation or I’ll have to find an alternate method of doing it myself.