Terahertz near-field radiation enhancement device based on two-dimensional electron concentration modulation

Abstract

The invention relates to a terahertz near-field radiation enhancement device based on two-dimensional electron concentration modulation. Femtosecond laser outputted from a laser light source is divided into two beams by a beam splitting piece. The beam splitting piece reflects the light beams to serve as pump light, the pump light is focused on a photoconductive antenna to generate terahertz waves, the terahertz waves enter a beam splitting grating field-effect transistor, bias voltage is applied to a grid electrode on a grating layer and a semiconductor layer of the beam splitting grating field-effect transistor, a defect cavity is formed in the semiconductor layer below the metal grid electrode, and terahertz near-field radiation passing the defect cavity can be enhanced. After transmitted light of the beam splitting piece is focused, the transmitted light serving as terahertz wave probe light is transmitted to a dielectric medium substrate on the other side of the beam splitting grating field-effect transistor, and the terahertz waves enhanced by the near-field radiation are detected. Terahertz near-field radiation intensity can be enhanced only by changing the bias voltage andadjusting concentration difference, and the device is easily set up, simple and convenient to operate and applicable to development of advanced technologies such as terahertz imaging technologies related to the terahertz near-field radiation intensity.

Description

technical field [0001] The invention relates to a terahertz near-field radiation enhancement technology, in particular to a terahertz near-field radiation enhancement device based on two-dimensional electron concentration modulation. Background technique [0002] In recent decades, terahertz waves have become an important research topic in the field of physics in the world due to its wide application prospects. Terahertz waves refer to electromagnetic waves (1THz=10 12 Hz), which lies between microwaves and infrared waves in the electromagnetic spectrum. The special electromagnetic spectrum position of terahertz wave makes it have many unique advantages: it has the characteristics of rich information, high space-time coherence, low photon energy, etc., and has great application value in scientific fields such as astronomy, biology, computer, and communication. At present, the main applied research includes terahertz time-domain spectroscopy technology, terahertz imaging te...

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Problems solved by technology

[0004] The present invention aims at the problem that there are great difficulties in enhancing the intensity of terahertz near-field radiation at present, and proposes a terahertz near-field radiation enhancement device based on two-dimensional electron concentration modulation. Voltage adjustment changes the movement of two-dimensional electrons on the semiconductor material graphene, forming a method of two-dimensional electron concentration difference to generate defect cavities, and stimulating the enhancement of terahertz radiation intensity

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