Polarization-Sensitive Nonlinear Optical Interaction of Ultrashort Laser Pulses with HPHT Diamond

The filamentation of focused 300 fs laser pulses with variable polarization azimuth in bulk synthetic HPHT diamond demonstrates the possibility polarization-dependent bandgap control for crystal dielectric photoexcitation. This directly affects value threshold power, which exhibits distinct dependence on angle. nonlinear photoluminescence yield, when focusing ultrashort diamond, indicates different regimes dynamics electron-hole plasma formation, arising due to processes photoexcitation and recombination free carriers during process. Thus, at onset process, relatively low intensities, yield rate depends controlling bandgap, while high intensities resulting dense absorbing isotropy respect radiation polarization, weakly azimuth.