Terahertz time-domain spectroscopy target three-dimensional scattering imaging measurement method

Abstract

The invention provides a terahertz time-domain spectroscopy target three-dimensional scattering imaging measurement method. The method is mainly based on an ISAR turntable imaging principle, a targetthree-dimensional scattering imaging test is carried out by utilizing terahertz time-domain spectroscopy scattering information of a two-dimensional rotating target, time-domain amplitude-phase signals of the target at different azimuth angles and pitch angles are obtained, and a target scattering three-dimensional image is obtained through frequency-domain imaging data screening and a THz image reconstruction data processing algorithm. The terahertz time-domain spectroscopy target three-dimensional scattering imaging measurement method provided by the invention is different from conventionalterahertz time-domain spectroscopy point scanning imaging, the terahertz time-domain spectroscopy emission wave beam fully irradiates the target, and the dimension of the test target can reach 10cm and is larger than that of a conventional sample of 1cm-2cm. Terahertz time domain pulse signals reflected by a target are tested through the measuring method, multispectral imaging information and a high-resolution three-dimensional scattering center of the target are obtained, and the target characteristic research and recognition problems are solved.

Description

technical field [0001] The invention relates to a technique for measuring electromagnetic scattering characteristics of a terahertz target, in particular to a three-dimensional scattering imaging measurement method for a terahertz time-domain spectral target. Background technique [0002] Terahertz (THz) time-domain spectral imaging is coherent imaging, based on the basic principle that the intensity and phase of THz electromagnetic waves transmitted through the imaging sample (or reflected from the sample) contain the spatial distribution of the complex dielectric function of the sample. The two-dimensional information of the intensity and phase of the transmitted THz electromagnetic wave is recorded, and the THz image of the sample is obtained after proper processing and analysis. [0003] Terahertz time-domain spectral imaging technology contains a lot of information. Each imaging point corresponds to a time-domain waveform, and the amplitude or phase of any data point c...

AI Technical Summary

Problems solved by technology

[0011] The patent application number 201821592358.8 "A reflective terahertz time-domain spectral imaging system" discloses an imaging system configuration, including: a laser and a spectrometer; the spectrometer includes: a first layer spectrometer and a second layer spectrometer; the second layer The spectrometer is arranged on the top of the first layer of the spectrometer; the first layer of the spectrometer includes: a delay unit and a polarization beam splitting unit; the second layer of the spectrometer includes: a terahertz generation unit and a sample testing unit; the polarization beam splitting unit is arranged at the output end of the laser, It is used to divide the laser light emitted by the laser into pump light and probe light, which are sequentially emitted along the first optical path and the second optical path; a terahertz generation unit and a sample testing unit are arranged in sequence along the first optical path; a delay unit is arranged along the second optical path , the exit end of the second optical path is set between the terahertz wave generating unit and the sample testing unit, effectively obtaining the reflected terahertz spectrum and image of the target to be tested, this utility model does not fully irradiate the target, and can only be used for one-dimensional imaging Measurement

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