Method for increasing resolution ratio of terahertz absorption spectrum by time-domain repair technology

Abstract

The invention discloses a method for increasing the resolution ratio of a terahertz absorption spectrum by a time-domain repair technology, wherein the frequency-domain resolution ratio is increased by removing the influence of reflection peaks and increasing the effective length of a terahertz time-domain signal through time-domain correlation locating, scale transformation and delay subtraction. The method comprises the following steps: step 1, obtaining time corresponding to the initial points, the valley points and the peak value points of main peaks and the reflection peaks; step 2, finding out the positions of the initial points, the valley points and the peak value points; step 3, extracting the peak values of the main peaks and the reflection peaks; step 4, calculating an attenuation factor; step 5, repairing a time-domain spectroscopy; step 6, obtaining a spectrogram; and step 7, calculating an absorption coefficient, and comparing absorption spectrograms before and after repair. The method is capable of accurately removing the reflection peaks of the time-domain signal, and effectively increasing the resolution ratio of the terahertz absorption spectrum.

Description

technical field [0001] The invention relates to the field of signal processing, in particular to the processing of terahertz time-domain spectral signals. Background technique [0002] For Terahertz (THz) spectral identification technology, since the vibration and rotational energy levels of a large number of molecules are just within the THz frequency range, Terahertz time-domain spectroscopy (THz-TDS) is used When the technology detects biological samples, it can effectively generate resonance absorption peaks, thus providing fingerprints for biological or macromolecular samples and making it possible to detect and identify them. However, due to the reflection of the detection crystal and the antenna substrate material, the THz light in the system will be reflected multiple times, and the measured time domain signal will have multiple reflection peaks. In order to remove the influence of the reflection peak, if the terahertz time-domain spectral signal is truncated before...

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Problems solved by technology

However, due to the reflection of the detection crystal and the antenna substrate material, the THz light in the system will be reflected multiple times, and the measured time domain signal will have multiple reflection peaks

In order to remove the influence of the reflection peak, if the terahertz time-domain spectral signal is truncated before the first reflection peak, according to Fourier transform theory, its spectral resolution will be greatly reduced, and the corresponding absorption spectrum resolution will also be reduced, which cannot reflect The fineness of the absorption spectrum, some two absorption peaks that are closely spaced are presented in the form of one peak, it can be said that the frequency domain spectrum with too low resolution is unreliable, thus affecting the identification of absorption peaks and the qualitative and quantitative analysis of substances

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