Abstrakt
Anisotropy of multiphoton carrier generation in monocrystalline Ha diamond and its dependence on the polarization state of excitation light (near-infrared few-cycle laser pulses) are investigated using photoluminescence and nonlinear absorption measurements. We observe anisotropy between multiphoton transition rates for light linearly polarized along the and crystallographic directions of diamond and a strong intensity-dependent decrease of the transition rate for circularly polarized light.
Measured results are compared with numerical simulations using time-dependent density functional theory and with an analytical model assuming a parabolic two-band system and the Houston function as the time-dependent wave function of the valence and conduction bands.