Anisotropy and polarization dependence of multiphoton charge carrier generation rate in diamond

Abstract

Anisotropy of multiphoton carrier generation in monocrystalline IIa 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 \ensuremath{\langle}100\ensuremath{\rangle} and \ensuremath{\langle}110\ensuremath{\rangle} 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.