Double-grating spectrometer system capable of detecting three-phase-state water Raman spectral signals simultaneously

Abstract

The invention discloses a double-grating spectrometer system capable of detecting three-phase-state water Raman spectral signals simultaneously. The system comprises a signal feed-in unit, an optical dispersion unit and a signal detection unit. The signal feed-in unit uses a fiber in the core diameter of 0.6mm and numerical aperture of 0.12 to feed conducted signal light into the optical dispersion unit; the optical dispersion unit comprises two cascaded grating dispersion systems of quasi-Littrow structural layout, can transmit and disperse passband signal light in the range 393.0-424.0nm in the focal plane efficiently in the linear dispersion rate of 1.0mm nm <-1>, and generates inhibition superior to 6 magnitude orders for outband light near 354.8nm; and the signal detection unit can distinguish and record the passabnd signal light after dispersion in the spectral precision of 0.8nm. In 354.8nm UV laser radiation, vibration-rotation Raman spectral regions of gas-sate, liquid-state and solid-state water correspond to the ranges of 395-409nm, 396-410nm and 401-418nm respectively; the passband spectral range covers the vibration-rotation Raman spectral regions of the three-phase-state water, the three-phase-state water Raman spectral signals are detected simultaneously, and substantial inhibition is generated for optical signals near 354.8nm.

Description

technical field [0001] The invention relates to a double-grating spectrometer system capable of simultaneously detecting vibration-rotation Raman spectrum signals generated by gaseous, liquid and solid water. Background technique [0002] Water is the only substance that can exist in a three-phase state in the atmosphere under natural conditions. Water vapor exists in the atmosphere all the time, and clouds are the main carrier of liquid water or ice water. The existence and changes of water vapor and clouds in the atmosphere will directly have a huge impact on the atmospheric environment. Accurately grasping the content, distribution and phase state of atmospheric water is very necessary in many atmospheric research fields. Achieving high-precision detection of atmospheric water requires great technical efforts. Water Raman lidar uses the vibration-rotational Raman spectrum of water to detect atmospheric water, which has the advantage of high temporal and spatial resolut...

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Problems solved by technology

At present, common commercial spectrometers are often not conveniently connected directly with the laser radar optical receiving system, which is not conduci...

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