In this paper, a high efficient terahertz source based on n-type gallium phosphide crystal via cryogenic process is investigated through collinear difference frequency generation pumper by 1064 nm Nd:YAG laser and its OPO system. Absorption coefficient of this crystal at THz range shows a dramatic decrease from ~ 50 cm^-1 to 0.5 cm-^-1 as the temperature decreases from 300 k to 80 k. Four times enhancement of the terahertz emission power and much more broad spectra range (~ 0.2- 3.8 THz) has been achieved in this kind of 0.5 mm length gallium phosphide crystal during the whole varied temperature difference frequency generation from 300 k to 80 k. These results indicate that cooling down the crystal temperature is an effective way to improve the terahertz source property, such as terahertz output power and frequency range.

Date Published: 29 March 2019
PDF: 7 pages
Proc. SPIE 11046, Fifth International Symposium on Laser Interaction with Matter, 1104631 (29 March 2019); doi: 10.1117/12.2524100

Published in SPIE Proceedings Vol. 11046:
Fifth International Symposium on Laser Interaction with Matter
YiJun Zhao, Editor(s)