Coherent detector for atmosphere greenhouse gas

Abstract

The invention discloses a coherent detector for atmosphere greenhouse gas. The coherent detector comprises a light cylinder, a solar tracking device, a collimation optical telescope, a chopper, a local oscillation laser, an optical fiber combiner, a high-speed photoelectric detector, a square law detector, a radio frequency amplifier, a video frequency amplifier, a locking amplifier and a microprocessor. According to the coherent detector for the atmosphere greenhouse gas, by referring concepts of a wireless heterodyne receiver and coherent detection, only when sunlight radiation components ofwhich wavelength is equal to that of laser output by the local oscillation laser are subjected to coherent detection, signals required by people can be output, and the spectral resolution of a sun photometer is increased. The coherent detector for the atmosphere greenhouse gas has the advantages that the contradiction between the sunlight detectivity and spectral resolution of an original photometer is solved, and the coherent detector is suitable for measurement of column concentration of atmosphere greenhouse gas components such as water vapor, carbon dioxide and methane.

Description

Technical field [0001] The present invention relates to a coherent detector, in particular to a low-power, narrow-linewidth semiconductor laser as a local oscillator light source, and performs a frequency mixing coherent detection with sunlight received by a collimating telescope to tune the wavelength of the local oscillator light. Obtain the atmospheric greenhouse gas coherent detector for a certain segment of the characteristic absorption spectrum distribution in sunlight. Background technique [0002] Fully automatic solar photometer, used to measure the radiation of the sun and sky in different bands, different directions, and different times of visible light and near-infrared, to calculate the characteristics of atmospheric aerosol, water vapor, ozone and other components. This instrument is portable and reliable. High degree of automation, solar power supply, long-term unattended automatic observation in the field, measurable sky diffuse radiation distribution, polarized r...

AI Technical Summary

Problems solved by technology

[0004] However, the disadvantage of the current sun photometer is: the spectral resolution is low, and the spectral resolution depends on the half-wave bandwidth of the filter used, generally 10nm, so it has a serious shortage in detecting the fine spectrum of atmospheric components

Of course, there is a contradiction between the spectral resolution and detection sensitivity of the sun photometer. When the filter bandwidth is narrow, the spectral resolution is high, and the brightness of solar radiation reaching the detector through the filter decreases, and the detection signal-to-noise ratio decreases.

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