Laser power fluctuation monitoring and compensating device and method for photoacoustic spectrum measurement

Abstract

The invention discloses a laser power fluctuation monitoring and compensating device and method for photoacoustic spectrum measurement, and belongs to the technical field of photoelectric detection. Two quartz tuning forks are adopted at the same time for measurement; one quartz tuning fork is used for monitoring the fluctuation of the laser power; the other quartz tuning fork is used for measuring photoacoustic spectrum; the influence of the laser power fluctuation to the photoacoustic spectrum measurement is removed by processing the signal output by the quartz tuning fork used for measuring the laser power, and then compensating the measurement result of the photoacoustic spectrum; the fluctuation of the laser power is inhibited. The device is reasonable in design, simple in structure, and easy to realize; the method can monitor the laser power in real time, and compensate the fluctuation of the laser power, so as to inhibit the fluctuation of the laser power; the problem that the photoacoustic spectrum detection is interfered by the fluctuation of the laser power is solved.

Description

technical field [0001] The invention belongs to the technical field of photoelectric detection, and relates to a laser power fluctuation monitoring and compensation device and method for photoacoustic spectrum measurement. Background technique [0002] Photoacoustic spectroscopy is a spectral technique developed based on the photoacoustic effect. Photoacoustic spectroscopy measures the amount of light energy absorbed by an object. It can measure strong light scattering and opaque objects that are difficult to measure by traditional spectral methods, and the samples can be measured whether they are crystals, powders, colloids, etc. It has high sensitivity and wide application range. advantage. It has broad application prospects in physics, chemistry, chemical industry, geology, biology, medicine and other aspects. [0003] In the current research on the application of quartz tuning forks in the field of gas detection, due to the widespread use of wavelength modulation techn...

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Problems solved by technology

[0003] In the current research on the application of quartz tuning forks in the field of gas detection, due to the widespread use of wavelength modulation technology, the final measurement of mass spectral lines is less affected by laser power fluctuations, and laser power fluctuations will only cause changes in the shape of absorption lines. It will affect the position of the spectral line, so when the wavelength modulation technology is used, the laser power is generally not monitored

[0004] In the current photoacoustic spectroscopy detection using the light intensity modulation method, the power fluctuation of the laser will interfere with the detection process, resulting in errors in the spectral measurement of the substance, which will affect the identification of the substance. The impact of photoacoustic spectroscopy measurement requires real-time monitoring and compensation of the output power of the laser. In photoacoustic spectroscopy telemetry, a tunable quantum cascade laser with a wavelength in the mid-infrared band is required. Since the optical power in this band uses ordinary It is difficult to detect the photodetector of the laser, and the existing methods and devices for detecting the power of the mid-infrared laser are often very expensive and need to be refrigerated, resulting in an increase in the cost and complexity of the entire equipment, which is not conducive to instrumentation

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