Temperature dependence of terahertz radiation from n-type InSb and n-type InAs surfaces

The azimuthal angle dependence and the temperature dependence of terahertz (THz) radiation generated from n-type (111) InSb and n-type (111) InAs surf aces irradiated with similar to 80 fs near-infrared laser pulses are invest igated. The azimuthal angle dependence shows that the contribution of the d ifference-frequency mixing (DFM) is not dominant for both materials at the excitation density of similar to 1 GW/cm(2). At an appropriate azimuthal an gle, the radiation due to DFM is excluded from the total THz radiation and the temperature dependence of THz radiation due to the surge current is obs erved. The increase of THz radiation with decrease of the temperature is fo und to be much more pronounced for InSb than for InAs. The different temper ature dependence can be attributed to the different radiation mechanisms do minant for both materials. Especially, the temperature dependence of the TH z radiation from InSb is well explained by the photoDember effect.