Terahertz generation using a ZnGeP2 photoconductive antenna

Photoconductive antennas (PCAs) are promising sources of relatively high energy asymmetric terahertz (THz) pulses with high pondermotive potentials [1] . The most studied PCA substrates are GaAs [2] , ZnSe [3] , and 6H-SiC [4] . The chalcopyrite ZnGeP 2 (ZGP) is a media with high nonlinear properties in mid-IR and THz range [5] . However, it has not been previously studied as a PCA substrate. The second harmonic (SHG) of Ti:Sa laser, SHG of Yb-based femtosecond lasers (Yb:KGW and Yb-fiber laser) can be used to excite ZGP above the bandgap, since the bandgap energy of ZGP is 2.2 eV. Therefore, it can be possible to create a compact THz emitter. The measured value of the ZGP volume resistivity is 470 •10 6 Ω•cm, and the surface breakdown field is 70 kV/cm. Consequently, a high bias field can be applied. Thus ZGP is a promising material as a PCA substrate.