Abstract

The physics of THz-radiation sources has been intensively studied for applications to sensing, imaging, and time-resolved spectroscopy. Zhang et al. reported quadratic dependence of laser induced THz radiation on a magnetic field.¹ Previously, we reported the significant enhancement of THz-radiation power from InAs in a magnetic field irradiated with femtosecond optical pulses, owing to the quadratic dependence on the magnetic field and excitation power.² Moreover, we had found saturation and a decrease of THz-radiation power in a stronger magnetic field.³ From the viewpoint of applications, this was a significant finding for practical light source design. This saturation and drop in radiation in a stronger magnetic field were also confirmed by other groups.⁴ However, the mechanism of such anomalous magnetic-field dependence has still not been clarified. The magnetic-field dependence of the radiation for various other semiconductors will provide important information for exploring such a mechanism. InSb and InP were selected as the other semiconductors because they have smaller electron-mass than InAs.⁵ In this presentation, we report the anomalous magnetic-field- direction dependent saturation, decrease, and recovery of THz-radiation power from femtosecond-laser irradiated InSb and InP in a strong magnetic field.

© 2002 Optical Society of America