NANOSECOND TIME-RESOLVED DEGENERATE 4-WAVE-MIXING MEASUREMENTS OF SMALL PD PARTICLES - THERMAL PHASE GRATING ANALYSIS

Reflection by the thermal phase grating formed in methanol containing small Pd metal particles has been measured by using a degenerate four- wave mixing optics equipped with a nanosecond Nd:YAG laser and a strea k camera. Although the integrated intensity of the reflection depended on the cubic power of the laser intensity the temporal profile of the reflection in a pulse duration showed the delayed response, the theor etical profile of which has been formulated by considering the formati on of thermal phase grating. The theoretical calculation based on heat conduction equation was in good agreement to the experimental results with respect to the shape of the profile, the intensity, and the pola rization dependence. (C) 1996 American Institute of Physics.