Theoretical studies of the electronic structures and linear, nonlinear optics of K 3− xLi 2+ xNb 5O 15 with x = 0 and x = 1

Abstract

The electronic structures of the ground state have been calculated using the INDO/1-SCI method, and in combination with the sum-over-states method, the first and second frequency dependent polarizabilities have been obtained for microscopic species of K 3− x Li 2+ x Nb 5O 15 with x = 0 and x = 1. The calculated birefringences δn and phase matching nonlinear optical coefficients d 31 indicate that the K 3− x Li 2+ x Nb 5O 15 with higher lithium content will enhance nonlinear optical effects at the fundamental wavelengths of 1064 and 820 nm. The charge transfer states formed from oxygen atomic 2p orbitals with a mixing of niobium atomic 4d character to alkali metal atomic valence orbitals with mixing of niobium 5s, 5p character make the most significant contributions to the susceptibility.