Abstract

We have studied nonlinear optical effects in a PTS-polydiacetylene single crystal in a Fabry-Perot cavity. A PTS crystal about 200 μm in thickness was placed between two mirrors having a reflectivity of 80% to construct the cavity. The cavity length was varied by using a piezoelectric drive to tune the cavity to specific bias points on the Fabry-Perot fringes. The measurement was made by a pump-probe technique using 90-ps pulses (82 MHz) at a 1.06-pm wavelength. The changes in the transmission were measured as a function of the time delay at the selected bias points. The results for two bias points are shown in Fig. 1. As expected, the response time was pulse- width limited, and large changes in transmission (~50%) were observed at low intensities. The direction of the fringe shift indicated a negative sign of n₂. This observation of the ulrafast intensity modulation suggests possibilities of significant applications of PTS Fabry-Perot étalons in subpicosecond switching and logic operations at high repetition rates.

© 1994 Optical Society of America