Abstract-High efficient terahertz generation from cryogenic gallium phosphide based on collinear difference frequency

Jingguo Huang, Yang Li, Yanqing Gao, Gaofang Li, Zhiming Huang, Junhao Chu, Yury Andreev

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11046/1104631/High-efficient-terahertz-generation-from-cryogenic-gallium-phosphide-based-on/10.1117/12.2524100.short?SSO=1

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.

© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Abstract-Evolution of terahertz conductivity in ZnSe nanocrystal investigated with optical-pump terahertz-probe spectroscopy

Gaofang Li, 

Xin Xue, 

Xian Lin, 

Sannan Yuan, 

Naiyun Tang, 

Fenghong Chu, 

Haoyang Cui, 

Guohong Ma

http://link.springer.com/article/10.1007%2Fs00339-014-8481-5

Ultrafast carrier dynamics and terahertz conductivity of ZnSe nanocrystal are investigated by means of the optical-pump terahertz-probe spectroscopy at room temperature. With the laser pulse excitation at 400 nm, the negative transmission of terahertz pulse shows an ultrafast rising followed by a biexponential recovery. The fast decay component with time constant of 5 ps is dominated by the photocarriers backscattering at interfaces of ZnSe nanoparticles, and the slow one with time constant longer than 1 ns can be assigned to the carrier recombination from band-to-band transition. The evolution of conductivity with time demonstrates that this kind of nanostructure is a good candidate for fabricating ultrafast terahertz switching.

Abstract-Evolution of terahertz conductivity in ZnSe nanocrystal investigated with optical-pump terahertz-probe spectroscopy

Gaofang Li, 

Xin Xue, 

Xian Lin, 

Sannan Yuan, 

Naiyun Tang, 

Fenghong Chu, 

Haoyang Cui, 

Guohong Ma

http://link.springer.com/article/10.1007/s00339-014-8481-5
Ultrafast carrier dynamics and terahertz conductivity of ZnSe nanocrystal are investigated by means of the optical-pump terahertz-probe spectroscopy at room temperature. With the laser pulse excitation at 400 nm, the negative transmission of terahertz pulse shows an ultrafast rising followed by a biexponential recovery. The fast decay component with time constant of 5 ps is dominated by the photocarriers backscattering at interfaces of ZnSe nanoparticles, and the slow one with time constant longer than 1 ns can be assigned to the carrier recombination from band-to-band transition. The evolution of conductivity with time demonstrates that this kind of nanostructure is a good candidate for fabricating ultrafast terahertz switching.