Generation of terahertz frequencies by picosecond optical excitation of narrow-gap semiconductors

Abstract

The new method based on the pulsed complex photomagnetoelectric (PME) effect has been proposed for generation of high frequency oscillations. The dynamics of PME photoresponse have been investigated experimentally in semiconductors InAs and CdxHg1-xTe (x=0.2 and 0.26) excited by Q-switched neodymium-YAG laser. The double sign inversion of the photoresponse signal was found at laser light flow I0 > 5 נ1024 photons/cm2s in InAs and at I0 > 1-4 נ1024 photons/cm2s in CdxHg1-xTe. Study of the frequency spectra of the doubly-sign-inversion signal of PME response applying DFT analysis reveal that, the spectra are broadened significantly in the region of high frequencies. The results exhibit the possibility to reach THz frequency range using laser pulses of the picosecond duration.