Optics In Paris

I've learned a ton this summer and its hard to sum it all up in one final video! But here goes :) Some days I love that there is always another question to answer in research, you're never really finished. Other days, its hard to realize I'll never know "enough." I'm so grateful to my mentors this summer, Jeff and Vitor, and for the team at the University of Michigan that made this possible! 

 I spent the last week of my internship working with Liquid Crystal Samples! I'm calculating their Mueller Matrices, just like I did earlier with the nanorods. Liquid Crystals are cool because their molecular organization gives them interesting optical properties, like the polarization changes I was measuring. The liquid crystal interacts with the laser and, in the future, we could the the Mueller Matrix setup I've been working on at the same time we use the Spatial Light Modulator others students worked with to really understand these crystals better.  Here you can see how the liquid crystals "change color" with different polarized light! We call this "Dichrosim." 

 It was really cool to work with the Scanning Electron Microscope! Our goal was to match results from the SEM to the polograms I've been creating. When I prepared the samples, I marked the region of interest on the bottom of the slide, so I wouldn't mess anything up on the sample itself. But that meant we couldn't find the spot once the slide was in the SEM! We took it out, and added tape to guide us to the correct place, but once I took the tape back to the dark field optical microscope, the tape's signal overpowered everything else. If I could do it again, I would use the marker on the surface of the slide with the nanorods to avoid the whole problem, but even with all of the hiccups, I learned a ton!  Here are some of the SEM images!!  

 

 

Tomorrow is the ultimate test of everything I've done so far! I've been trying to figure out the orientation of nanorods with polarized light, but until now I haven't had an answer key to compare my results with. The nanorods are too small to determine how they are oriented with visible light, so we have to turn to something with an even smaller wavelength. That's where the scanning electron microscope comes in! Since electrons have a much smaller wavelength than visible light, we can create a topographical map of my sample. If the polarization method I've been working on matches the map, we win!  To get ready, I prepared more nanorod samples on special, conductive slides. Today I took them into the lab and compared them with the regular glass slides to see if the nanorods were deposited correctly. That's where it got complicated. The conductive slides are much thicker than the glass slides and were impossible to view with the 40x objective we were using. The sl