Analysis of the effect of phase-mismatch and material absorption on the terahertz-wave generation from GaSe

We analyzed the effect of phase-mismatch and material absorption on the terahertz-wave difference-frequency generation from GaSe theoretically. We calculated the best length of crystal and the corresponding terahertz power under four different conditions and the effect of angle-mismatch on phase-mismatch. The result provided a theoretical basis and reference to nonlinear optical difference-frequency experiments.