Method for measuring material parameter and material thickness by using terahertz pulse

Abstract

The invention discloses a method for measuring a material parameter and a material thickness by using a terahertz pulse. The method comprises the steps of measuring a reference signal and a sample signal; extracting the pth time of echo signal from the sample signal and obtaining an experiment value of a corresponding transmission coefficient; measuring a measurement value of a sample thickness L; building a main peak / echo transmission model; calculating a transmission coefficient calculation value corresponding to the pth echo signal; calculating a first material electromagnetic parameter and a second material electromagnetic parameter; calculating a total difference value function of the material parameter; if the total difference value function of the material parameter meets the preset conditions, taking the sample thickness corresponding to the total difference value function of the material parameter as an accurate thickness of the sample to obtain the calculation value of the transmission coefficient corresponding to a main peak corresponding to the sample thickness L; and calculating a real part and a virtual part of a corresponding sample complex refractive index. By using the above method, the material parameter of an optical thick sample can be accurately determined and the material parameter and thickness of a terahertz pulse period can be measured at the same time.

Description

technical field [0001] The invention relates to the field of laser technology, in particular to a method for measuring material parameters and material thickness by using terahertz pulses. Background technique [0002] Terahertz waves generally refer to electromagnetic waves with wavelengths from 30 microns to 3 mm and frequencies from 0.1 to 10 terahertz. Terahertz waves are between infrared and millimeter waves, and have a fairly wide spectrum. Because terahertz waves are in the transition region between photonics and electronics, they can provide information that traditional detection methods such as visible light or microwaves cannot provide, so they have great application prospects in the fields of physics, chemistry, and biomedicine. [0003] In the field of terahertz wave research, terahertz time-domain spectroscopy system is a very important and widely used technology. The principle of this technology is: first mix the terahertz pulse and the sampling detection pul...

AI Technical Summary

Problems solved by technology

[0036] However, the thickness of non-optical transparent materials cannot be measured by optical methods, and other existing methods, such as X-ray, beta backscattering, Eddy current method and conductometric method, may have large investment, long measurement period, Measurement of defects such as single material and inability to measure samples that are too thick (millimeter level)

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