Improvement to Sellmeier equation for periodically poled LiNbO3 crystal using mid-infrared difference-frequency generation

L.H. Deng, X.M. Gao, Z.S. Cao, W.D. Chen, Y.Q. Yuan, W.J. Zhang and Z.B. Gong

Abstract

Improvement to the Sellmeier equation for the extraordinary index of periodically poled LiNbO3 crystal (PPLN) is reported. The equation has been improved based on a continuous tunable mid-infrared radiation realizing in a PPLN crystal using difference-frequency-generation (DFG) and quasi-phase-matching (QPM) technique. The improved equation is suitable to estimate the QPM conditions of PPLN crystal for temperatures between 25 °C and 180 °C and mid-infrared wavelengths ranging from 2.8 μm to 4.8 μm.