Terahertz wave amplification device based on optical pumping substrate-free graphene

Abstract

The invention discloses a terahertz wave amplification device based on optical pumping substrate-free graphene. The terahertz wave amplification device comprises a THz (terahertz) radiation generation device, a THz radiation amplification device and a THz radiation detection device, wherein the three devices share a femtosecond laser through a beam splitter. Incident femtosecond optical pulses are divided into two beams through the beam splitter, wherein one beam is of an optical detection path for entering into the THz radiation detection device, the electro-optic sampling detection principle is utilized for detecting generated and amplified terahertz pulses; the other beam is further divided into two beams, namely Beam 1 and Beam 2 via the other beam splitter; the Beam 1 is of THz generated light, the optical rectification effect is utilized to generate THz radiation on the surface of a nonlinear crystal, and the radiation is irradiated onto the substrate-free graphene via an off-axis parabolic mirror as signal light; and the Beam 2 is of pumping light of the graphene, the substrate-free graphene is stimulated to realize population inversion of a current carrier, and stimulated amplification of the THz radiation is realized on the action of the THz signal light.

Description

technical field [0001] The invention relates to the field of terahertz technology, in particular to a device for amplifying terahertz waves by pumping substrate-free graphene through light to achieve negative conductivity of the graphene. Background technique [0002] THz radiation sources can be divided into two categories from the perspective of their generation mechanism: THz radiation sources based on electronics and THz radiation sources based on optics. At present, the main optical methods are nonlinear optical difference frequency method and THz wave parametric oscillation method, optically pumped THz wave gas laser, related to ultrashort laser pulses, optical rectification, photoconduction and plasma that can generate broadband sub-picosecond THz radiation methods such as volumetric four-wave mixing. [0003] Among them, femtosecond laser pulses are used to pump nonlinear crystals to generate THz radiation through the optical rectification effect, which is to use fe...

AI Technical Summary

Problems solved by technology

Due to the transfer of charge from SiC to the bottom graphene in contact with the SiC surface, the graphene layer has a high conductivity, and the Drude absorption makes it absorb radiation in the terahertz band range, and absorb the radiation of other graphene layers. THz waves have a negative effect on achieving THz amplification, so this method is not efficient in achieving THz amplification

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