Self-stable light splitting technology for four wave mixing experiment

Abstract

The present invention discloses a self-stabilized spectroscopic technology in a four-wave frequency mixing experiment. If the DFWM spectral technology needs to be practical, the stability problem of the light path is solved first. The technology comprises two prefect reflection mirrors and two purpose-made beam splitters. The beam splitter BS1 (1) is arranged in parallel with the perfect reflection mirror M1 (2), and forms an angle of 45 degrees in the direction of the laser beam outputted from a dye laser (3). After split by the beam splitter BS1 (1), the laser beam V is subjected to the perfect reflection mirror M1 (2), the beam splitter BS2 (3), the perfect reflection mirror M1, the beam splitter BS2 and the perfect reflection mirror M2 (4), thereby forming four beams which are of the same light propagation direction and parallel with each other and vertical spatially, and forming a rectangle by the propagation direction. By adjusting the distances between the two perfect reflection mirror (M) and the two purpose-made beam splitters (BS), a square is formed. After focused by a focusing lens f1 (5), the light spots of the two light beams are overlapped. The technology is applied to the field of optics.

Description

Technical field: [0001] The invention relates to a self-stable light splitting technology used in four-wave mixing experiments. Background technique: [0002] Compared with other spectroscopic techniques (such as LIF and CARS), degenerate four-wave mixing (DFWM) spectroscopy has the advantages of high sensitivity, high resolution, and high signal-to-noise ratio, and is widely used in trace Quantitative measurement of atoms, molecules and free radicals. At the same time, due to the good anti-background interference ability of DFWM spectroscopy, DFWM is also used for the detection of trace elements in combustion flames and the measurement of combustion temperature. Since Ewart et al first used DFWM spectroscopy to detect the weak absorption of OH groups in methane-air combustion flames under atmospheric pressure in 1986, DFWM spectroscopy has made great progress in laboratory research. Using this technique, Farrow et al. obtained H 2 -O 2 -N 2 NOA in combustion flame 2 ∑...

AI Technical Summary

Problems solved by technology

In general, changes in the working environment (especially changes in temperature) will cause the laser beam to drift slightly in the direction of spatial propagation, while DFWM requires that the three pumped laser beams strictly overlap with one point, and the cross-section of the overlapping area is about 100 microns level; if there is a slight drift between the three incident pump lasers, it will lead to instability or even disappearance of the output DFWM signal

It can be seen that if the stability of the optical path is not solved, the DFWM spectroscopy technology will be difficult to obtain practical applications

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