Temperature Dependence of Terahertz Properties of Stoichiometric Lithium Tantalate.

We studied terahertz (THz) optical and dielectric properties of stoichiometric lithium tantalate (sLT) from room down to liquid nitrogen temperature in the range of 0.15–1.8 THz using terahertz time-domain spectroscopy. Two-oscillator Lorentz models were fitted well to the crystal properties for both ordinary and extraordinary waves. We also studied changes in sLT ultraviolet (UV) absorption from room to liquid nitrogen temperature. The measurements showed a significant drop in absorption in both the THz and UV ranges with cooling. According to these results cooling should increase lithium tantalate potential in optical-to-terahertz conversion of high-power 800-nm radiation. The measured properties can be used in designing nonlinear optical conversion schemes and devices based on sLT. [ABSTRACT FROM AUTHOR]