Abstract

A lot of THz-radiation sources have been intensively studied for applications to sensing or imaging, and a time-resolved spectroscopy.^1,2 We have demonstrated the significant enhancement of THz-radiation power from InAs in a magnetic field irradiated with femtosecond optical pulses.³ In this case, the InAs emitter was at room temperature and was kept in the air without any special treatment. For practical light source development, it is meaningful to know whether some kind of surface treatment will effectively enhance the radiation intensity or not. Additionally, it is well known that the generation mechanism of THz radiation from the semiconductors is closely related with its surface.⁴ Therefore, characterization of the THz radiation from well-controlled surfaces at various temperatures will also be interesting from the viewpoint of physics. In this presentation, we report the strong enhancement of THz radiation from an InAs irradiated with femtosecond laser pulses after surface cleaning and cooling.

© 1999 Optical Society of America