From previous AOEO tests we learned that cascaded AO and EO can work. However, the method we were using for EO created discrete changes. In discussing how to move towards more continuous changes, we decided we would have to greatly increase cost and fabrication difficulty to continue with EO. We then decided to try a continuous resistive bridge which should heat up and cause the phase shift we are looking for.

100x1000um channel with 200um wide 25nm deep NiCr RS triangle centered.

Results: 70nm NiCr gives us a good resistance to work with. (Somewhere between 50 Ohms). The NiCr absorbs most of the light in the streak, but we were able to see movement. The power supply showed a max of 0.08A at about 12V. Took a video.

100x2000um channel with 200um wide 70nm deep NiCr RS triangle centered on top of a layer of SiO2 to help the light propagate underneath.

Results: SiO2 layer helps light propagate underneath, but changes level of connectivity of NiCr so we need to run more depth tests (for thinner NiCr) to get the resistance we want. Or it wasn't connected because SiO2 overlapped the Al.

SUCCESS! We got movement. See video from 1/27/2017. This device had a 150um channel with silicon dioxide and a nichrome bridge. This device was from a wafer initially processed by Dr. Smalley. (Al pads etched, wafer proton exchange process, SiO2 evaporated over the entire wafer. I patterned the SiO2 to expose the prism coupling area and the Al pads, then etched with buffered HF. I immediately patterned the device again and evaporated NiCr, possibly allowing the NiCr to electrically connect better with the Al. During testing this device only lasted up to about 3V and 0.04A but had noticeable smooth deflection of a single line. Unsure as to why it didn't work past this point. I assume some connection issue. Response time was very good. Deflection seemed to be in real time as I increased power.

Got a little more movement today. See video from 1/30/2017. Still have two large problems: dimness with the characteristic streak leading to low contrast on output and a tendency for the device to stop working after a certain power threshold is met. (Somewhere around half a watt). For the dimness I expect the problem to have been either in the proton exchange full wafer process or the SiO2 evap method/thickness, etc. I have started another batch of single samples that I will run through my previously successful proton exchange process to see if this helps.