AP0868 Study of Transient Laser-Induced Self-Focusing and Optical Modulation of Porous Silicon Films Using Pump-Probe Spectroscopy

Abstract

The transient transmittance change of microprous silicon was measured using optical pump – Mid infrared probe technique at different laser fluences. The results confirmed the existence of self-focusing in such structures at small incident angles and proper laser flounce. The measurements indicated that the self-focusing is not a long process which lasts for a short period of time. The tuneable focusing of MIR probe can be achieved with no need of adding any additional inclusions to the sample. This in turn provides the ability of sharpening or de-sharpening the profile of the probe beam.  This also enables the utilization of such structures in the realm of stimulated depletion microscopy. The optical modulation change is also investigated based on Maxwell Grannet model. The model showed that the optically generated charge carriers increase with increasing the pumping fluence allowing the use of such structures as a tuneable optical modulator.