Intensity-tunable terahertz radiation from tin selenide

Abstract

Recently, the active controlled broadband terahertz (THz) emitter from semiconductor crystal has attracted considerable attention due to its field intensity tuning properties, which makes it a promising candidate for wide applications in THz photonics. A broadband THz wave radiation intensity by applying electric field control in an n-type semiconductor tin selenide (SnSe2) crystal had been reported. In addition, due to the weak phonon absorption of the material in the THz band, the resulting THz spectral range is up to 3.5 THz. With an applied voltage of −5 V, the actively modulated depth of THz intensity is up to 123%. Our work directly demonstrates that when the excited laser photon energy exceeds the material bandgap, photon drag effect would be the main mechanism of THz wave radiation rather than nonlinear effects. Owing to simple structure and high modulation depth, electrically controlled THz radiation, the SnSe2 crystal has great applications in generation and modulation devices in THz region.