A device for improving the measurement accuracy of spectral absorptivity based on a terahertz optical comb

Abstract

The invention relates to a device for improving the test accuracy of spectrum absorbance on the basis of terahertz optical combs. The device is characterized in that one of two ultrafast laser pulse beams with set repeat frequency difference is transmitted through a terahertz wave generating system to generate terahertz waves, terahertz wave signals and the other ultrafast laser pulse beam are respectively focused and are jointly transmitted into a photoconductive detection antenna, the terahertz waves can be quickly scanned by the aid of tiny repeat frequency difference between pump beams and probe beams, a digital converter is controlled by the aid of a cross-correlation instrument and a rubidium atom frequency standard, the signal acquisition time is prolonged to obtain time-domain spectra of continuous terahertz pulse chains, terahertz comb-shaped spectra are obtained by means of Fourier transformation, accurate change of the optical combs is compared before and after sample placement, and accordingly terahertz absorption spectrum lines of samples can be obtained. The device has the advantages that the shortcoming of excessive scanning time consumption of mechanical delay devices can be overcome, the problem of inaccuracy of existing terahertz super-continuous spectra due to laser pulse time jitter can be solved, and the test accuracy of the terahertz spectrum absorbance can be improved.

Description

technical field [0001] The invention relates to a terahertz optical comb spectrum detection technology, in particular to a device for improving the measurement accuracy of spectral absorptivity based on a terahertz optical comb. Background technique [0002] With the development of a series of new materials and technologies, especially the development of ultrafast technology, the broadband stable pulsed THz source has become a quasi-conventional technology in the field of ultrafast technology, and has set off a THz research boom in the world. Terahertz waves refer to electromagnetic waves with a frequency in the range of 0.1 to 10 THz, which are located between microwaves and infrared in the electromagnetic spectrum, and have great application value in scientific fields such as communication technology, safety detection, and biological detection. [0003] Terahertz spectroscopy is known as an effective tool for detecting and characterizing material properties, mainly because...

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Problems solved by technology

[0004] The present invention aims at the problem that the test accuracy of terahertz time-domain absorption spectrum is not high at present, and proposes a device based on a terahertz optical comb to improve the test accuracy of spectral absorptivity. The device is simple, easy to operate, and avoids mechanical delay The shortcoming of too long scanning time of the device avoids the inaccuracy caused by laser pulse time jitter in terahertz supercontinuum spectroscopy, and improves the measurement accuracy of terahertz spectral absorptivity

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