Reading, Lab Work, and Skype

I spent this morning (Thursday) reading more in the optoelectronics text and then spent the afternoon in the lab. One thing that I was going to maybe look into is "dielectric relaxation time", which Antoine suggested as being a possible problem with our current setup.

In the lab this afternoon, we set up an optical delay on the ellipsometry setup and tried to synchronize the THz and excitation beams. We tested again to look for a signal with the Si sample and all of the GaAs samples, yet still found nothing. We also turned off the lights, but could still not detect any changes. Finally, we altered the position of the optical delay line to see if the path length made a difference for the two pulses, but could not really say whether or not it did because we were not able to detect any changes in the transmitted THz signal.

Finally, I talked tonight on Skype with John and learned a great deal of information and got some ideas for this project. A few notable things that we talked about are: carrier lifetime, Fresnel reflections, beam choppers, how a lock-in amplifier reads a signal, where to place the delay line, whether or not to focus the excitation beam, etc.