Method for improving frequency spectrum signal-to-noise ratio of tera-hertz optical detection system

Abstract

The invention relates to a method for improving the frequency spectrum signal-to-noise ratio of a tera-hertz optical detection system. According to the method, a space optical modulator is added into the tera-hertz optical detection system for conditioning pumping light, so that the generated tera-hertz spectrum is centralized to the frequency band with the concentrated sample absorption peaks so as to improve the definition and the signal-to-noise ratio of the tested sample characteristic spectral lines; the data accurate rate is ensured; convenience is provided for later-period data analysis. Compared with the existing method for improving the signal-to-noise ratio, a space optical modulator is regulated through a computer optimization algorithm; the influence on an experiment result due to other interference factors caused by artificial system regulation is avoided. The method belongs to a method for conveniently, fast and efficiently obtaining the high-signal-to-noise-ratio and high-precision tera-hertz frequency spectrum.

Description

technical field [0001] The invention relates to a signal processing technology, in particular to a method for improving the spectrum signal-to-noise ratio of a terahertz optical detection system. Background technique [0002] Terahertz (THz) waves refer to far-infrared electromagnetic radiation with a frequency between 0.1 and 10 THz (wavelength between 30 μm and 3 mm). area. It is precisely because of the special position of the terahertz wave band that terahertz has many unique properties, such as: good transmission, which can be used as a supplement to technologies such as X-ray imaging and ultrasonic imaging; safety, the photon energy of terahertz waves is very low, The photon energy of a terahertz wave with a frequency of 1THz is about 4meV, which is about 50% of the X-ray photon energy Times, so it will not produce harmful ionization to biological tissue, suitable for biopsy of biological tissue. The ability of spectral analysis is strong, and it contains rich spec...

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Problems solved by technology

[0004] The present invention aims at the problem that the current terahertz spectral modulation cannot meet the detection requirements of biological samples, and proposes a method for improving the spectral signal-to-noise ratio of the terahertz optical detection system. The method adds spatial light modulation to the terahertz optical detection system The pump light is modulated by the device, so that the generated terahertz spectrum is concentrated in the frequency band where the absorption peak of the sample is relatively concentrated, so that the signal-to-noise ratio of the detected spectral line is improved, and the characteristic peaks of the sample are richer and more obvious. Efficient and rapid method to obtain high signal-to-noise ratio and high-definition terahertz spectrum

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