Image point focusing method for four wave mixing technology

Abstract

The invention relates to an image point focusing method for four wave mixing technology; the four wave mixing, as an ultra-sensitive spectroscopic technology, is successful in detection field of trace amount atom, molecule and free radical; however, in the current experiments of forward four wave mixing, plural problems exist in focusing process. The composition of the invention comprises converging parallel rays and imaging onto CCD to obtain an overlapping area, the converged parallel rays is converged into a sample pool by three parallel ray beams with square top points on a vertical face on the basis of ignoring the influence of window panes on the convergence of the ray beams, the imaging onto CCD is implemented by imaging the image at the focus of another lens onto the back CCD, the obtained overlapping area precisely converges the three ray beams into the sample pool without moving the sample pool so as to obtain the overlapping area. The invention can be applied to the optics field.

Description

Technical field: [0001] The invention relates to an image point alignment method of four-wave mixing technology. Background technique: [0002] As a highly sensitive spectroscopic technique, four-wave mixing has achieved great success in the detection of trace atoms, molecules and free radicals. Compared with other spectral techniques, four-wave mixing spectroscopy has the following advantages: (1) Degenerate four-wave mixing (DFWM) spectroscopy has the characteristics of sub-Doppler spectral resolution, good time resolution and spatial resolution. Due to the high collimation and coherence of DFWM signal light, it can be used for long-distance detection, and can effectively eliminate background light, so there is no background noise. Due to its resonance characteristics, its detection sensitivity is higher than that of Anti-Stokes Raman Diffraction (CARS) spectroscopy; (2) DFWM uses direct detection of absorption, which is especially suitable for weak fluorescence or short ...

AI Technical Summary

Problems solved by technology

In this way, two consequences will be caused: one is to place the sample cell at the focal point after aligning the optical path each time, which can easily not ensure that the sample cell is at the focal point and may damage the optical path; It is a high-brightness and high-intensity light source, so when researchers use the method of direct observation with the naked eye to face the light in the experiment, it is very easy to damage the retina of the researchers' eyes

Secondly, even if the CCD is used to align the light at the focal point, there are still two problems: one is that every time the light is aligned, because the focal spot of the object image at the focal point is very small, it is difficult for the CCD to distinguish whether the four beams are placed at the same time. Coincidence at the focal point; the second is to place the sample cell at the focal point after aligning the optical path every time, which is easy to not ensure that the sample cell is at the focal point, and may damage the optical path

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