Device and method for measuring disturbance of cross flow fan impeller of pulsed gas laser

Abstract

The invention discloses a device and a method for measuring disturbance of a cross flow fan impeller of a pulsed gas laser. The device and the method are mainly used for measuring the disturbance of the fan impeller. The device comprises an exploring laser light source, a beam expanding system, two spectroscopes, two reflecting mirrors, a photoelectric detector, a data acquisition unit and a processor, wherein the two spectroscopes and the two reflecting mirrors form a Mach-Zehnder interferometric system; the two spectroscopes are respectively arranged at both ends of a flow field area to be tested; the exploring laser light source, the beam expanding system and a first spectroscope are located on the same light path in sequence; and the photoelectric detector is located on the emergent light path of a second spectroscope. The method comprises the following steps: performing filtering on a signal, and then performing fast Fourier transform (FFT) treatment on the signal through controlling the data sampling frequency and the number of samples; converting a periodic disturbance signal of a time domain into a signal of a frequency domain to obtain a signal spectrum so as to determine the disturbance of the fan impeller. According to the device and the method disclosed by the invention, the disturbance information of fan rotation is obtained through an optical measurement mode. The device and the method have the characteristics that the measuring device is simple and is high in precision and convenient in operation and the method is very high in practical applicability.

Description

technical field [0001] The invention belongs to the technical field of optical measurement, and relates to a measuring device and method for the impeller disturbance of a pulsed gas laser cross-flow fan, especially a measuring device and method for measuring the slight disturbance caused by a Mach-Zehnder interference system on the impeller of a cross-flow fan , the method is especially suitable for the measurement of the small disturbance of the impeller of the cross-flow fan in the pulsed gas laser cavity. Background technique [0002] Pulsed gas lasers pumped by pulsed discharges such as CO 2 Gas lasers and excimer lasers have been widely used in industrial processing, integrated circuit lithography, laser medical treatment and other fields. The uniformity of the working medium in the main discharge area of ​​a pulsed gas laser has an important impact on the discharge uniformity and the quality of the far-field beam. Therefore, a circulation system is needed to continuou...

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Problems solved by technology

However, the traditional Mach-Zehnder device cannot be directly used to measure the disturbance of the fan in the pulsed gas laser, because the disturbance generated during the rotation of the fan is a process of gradual change in gas density, and the density change in the entire observation area is not large, so it cannot be imaged by a CCD camera, etc. method to obtain effective information

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