"In my lab I study crystals whose indices of refraction change when light shines on them. This causes the crystals to diffract light in different directions. Some diffracted light goes exactly backward, opposite to the incident light. This light is called the phase conjugate wave. Simply speaking, we say that this wave has the ability to compensate for, or correct, the possible distortions in the original wave. So for example if you have a picture that you want to send through an optical fiber, and at the other end you get a blurred image, then using this crystal it's possible to get a clear image again.

Many people have studied this effect, but found that you only sometimes get a very stable signal. Most of the time there are many fluctuations. My students and I are trying to understand why the experiments behave in this way. We have found an interpretation that allows us to explain our experimental data quite well, at least for the behavior of the crystals we have studied so far.

Many optical devices use these crystals and the fluctuations present a big problem. My hope is that my students and I will find a way to control these instabilities. We are planning to study control mechanisms in my upcoming sabbatical year."