Excitation spectra of terahertz emission from semiconductor surfaces

Abstract Spectral dependences of THz radiation from laser-illuminated surfaces of InAs and InSb have been investigated experimentally at high optical fluences for laser wavelengths ranging from 0.6 μm to 2 μm. Efficient THz generation was discovered in the excitation range around 1.6 μm. The influence of inter-valley scattering was evident. The energy position of subsidiary conduction band valleys was evaluated to be equal to 1.08 eV and 0.53 eV for InAs and InSb, respectively.