Birefringence and Anisotropy of the Losses Due to Two-Photon Absorption of Femtosecond Pulses in Crystals

Abstract

It is shown that the two-photon absorption (TPA)-induced losses in a non-centrosymmetric crystal reduce considerably when the angle θ between the polarization vector of incident radiation and the optical c-axis is 45°. In such a geometry of interaction in a Ca3(VO4)2 crystal, the effective TPA coefficient for 300 fs laser pulses at θ = 45° is 3.5 ± 0.5 times lower than its maximum at θ = 0°, which is more than two times higher than reported earlier in the literature.

Keywords

• two-photon absorption
• femtosecond pulses
• anisotropy
• birefringence