A wavelength division multiplexing detection system with multiple similar wavelengths of laser radar

Abstract

The invention discloses a laser radar similar multi-wavelength wavelength division multiplexing detection system. The system comprises a lens, two polarization beam splitter-Glan polarizing prisms, five quarter wave plates, four convergent lenses, four detectors, four F-P etalons, a reflecting mirror and four ambient light filters. Light energy with no more than four wavelength components in a laser radar echo received by a telescope can be detected separately. When the echo contains four components with similar wavelengths, a laser echo of each wavelength selects different paths to travel according to a direction of a polarization component contained by the laser echo and then finally arrives at an assigned detector and does not enter into other three detectors so that wavelength division multiplexing detection is realized. The system has advantages that the system can detect energy of no more than four components with similar wavelengths which are mixed in the laser radar echo and detection efficiency is high; the system does not depend on polarization composition of each wavelength incident light and can be used in an occasion where the plurality of similar wavelengths need to be separated and each wavelength light energy needs to be detected.

Description

technical field [0001] The invention relates to a laser radar receiving system, in particular to a wavelength division multiplexing detection system with multiple similar wavelengths of the laser radar. Background technique [0002] The laser radar transmitter emits laser pulses of similar wavelengths successively in time. Because they are separated in time, the receiver can share the filter and detector, and the detection circuit can output signals successively. But sometimes the transmitter will emit laser pulses with similar wavelengths (2, 3, or 4 wavelengths) at the same time, and the receiver collects the laser echoes of these wavelengths through the telescope, but because the wavelengths are very close, it cannot even be used. A regular separation film or grating effectively separates it. For example, the Raman lidar detects the temperature of the troposphere, and the pure rotational Raman scattering echo excited by the 532nm laser needs to obtain the intensity of th...

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Problems solved by technology

But sometimes the transmitter will emit laser pulses with similar wavelengths (2, 3, or 4 wavelengths) at the same time, and the receiver collects the laser echoes of these wavelengths through the telescope, but because the wavelengths are very close, it cannot even be used. Regular color separation films or rasters effectively separate them

For example, the Raman lidar detects the temperature of the troposphere, and the pure rotational Raman scattering echo excited by the 532nm laser needs to obtain the intensity of the high-order 531.14nm and low-order 528.76nm components, but their wavelength difference is only 2.38nm, and they are excited at the same time Another example is to use 354.7nm laser to excite the pure rotation Raman scattering echo. It is necessary to obtain the intensity of the high-order rotation Raman354.07nm and the low-order rotation 353.25nm components, but their wavelength difference is less than 1.0nm, and they are excited at the same time The difference between the detection wavelength and the reference wavelength of the differential absorption lidar is often less than 1.0nm. There is no problem with the two kinds of optical pulses being emitted in turn. However, if they are emitted at the same time, necessary measures must be taken to solve the separation and detection of the echoes.

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