Automatic terahertz atmosphere characteristic measuring system and calibration method thereof

Abstract

The invention discloses an automatic terahertz atmosphere characteristic measuring system and a calibration method thereof; the system comprises a calibration signal source, a calibration device, a terahertz spectrometer and a system control device; the calibration signal source is a double-temperature calibration signal source based on nature ambient temperature, i.e., a passive work mode can effectively simplify the calibration device and improve the system calibration precision, thus ensuring the system to carry out long term consistent unmanned works; the terahertz spectrometer is a dual-frequency band overlapping ultra wide band MPI type terahertz Fourier spectrometer, and employs a two-port input and two-port output mode; a black body calibration signal source or an atmosphere radiation signal source and a built in reference blackbody signal source are inputted so as to form interference fringes under an interferometer effect; the interference fringes are outputted to two detectors with different detection frequency band ranges yet overlapping on the low frequency band; the two detectors respectively singly receive and output interference fringe electric signals, and the signals are corrected, accumulated and averaged in a frequency domain, thus improving the overlapping frequency band observation calibration data signal to noise ratio.

Description

technical field [0001] The invention relates to a terahertz astronomical site atmospheric characteristic measuring device and a calibration method, belonging to the field of terahertz technology research and application. Background technique [0002] The terahertz band (0.1-10THz) is between the microwave and optical bands, and is a new band that still needs to be fully developed and researched. Since nearly 50% of the photon energy in the universe and a large amount of molecular spectral line radiation fall in the terahertz band, and this band is most suitable for observing the early cold and dark universe, the terahertz band is a unique band for cosmology and astrophysics research. Due to the serious absorption of terahertz radiation by the earth's atmosphere, especially water vapor, ground-based terahertz astronomical observations require a high-altitude, dry, and low-temperature environment. It is an important task in the early stage of the construction of a terahertz o...

AI Technical Summary

Problems solved by technology

The low-temperature calibration source generally adopts the black body signal source in the liquid nitrogen temperature zone, which brings about problems: because liquid nitrogen is easy to dissipate into nitrogen gas, continuous and effective work for a long time (such as anniversary) cannot be achieved; in addition, liquid nitrogen needs to be stored in Insulated sealed liquid nitrogen tank

A single detector technology solution will limit the measurement of wider-band terahertz atmospheric transmittance, especially when a wider frequency range (such as including the 5-15THz interval) is required to fully evaluate the characteristics of water vapor rotation spectrum and unsaturated water vapor radiation line spectrum on atmospheric transmittance Affected situation

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