Laguerre-gaussian beam-based speckle contrast imaging measurement device and laguerre-gaussian beam-based speckle contrast imaging measurement method

Abstract

The invention relates to a laguerre-gaussian beam-based speckle contrast imaging measurement device and a laguerre-gaussian beam-based speckle contrast imaging measurement method. The device comprises a continuous wave laser; after being reflected by a total reflective mirror, a light beam emitted by the continuous wave laser irradiates on a collimating beam expander; after that, the light beam becomes linearly polarized light by a polarizer and then irradiates on a beam splitting prism; after passing through the beam splitting prism, the light beam is divided into two beams, wherein one path is reflected light, and the other path is transmission light; the reflected light beam irradiates on a spatial light modulator, and the light beam reflected by the spatial light modulator irradiates on a diaphragm after passing through the beam splitting prism and an analyzer again; after passing through the diaphragm, the light beam irradiates on a sample to be tested; after being scattered by the sample to be tested, the light beam is converged by an imaging lens, and then an image is formed in a charge coupled device (CCD) camera; after that, the image is stored in a computer, and the image contrast value can be calculated; when a light path is difficult to adjust, the speckle size is adjusted by changing the characteristics of the illumination beam, so that the method has the characteristics of being flexible and reliable; the method is widely applied to the fields such as hemorheology monitoring, plant growth condition monitoring, etc.

Description

technical field [0001] The present invention relates to a speckle contrast imaging measurement device and method, in particular to a speckle contrast imaging measurement device and method based on Laguerre-Gaussian beams. Background technique [0002] Laser speckle refers to the bright and dark spots formed after the diffuse reflection light interferes with each other in the reflection space when the laser is irradiated on the surface of a rough object. Speckle carries the information of the measured object, and the change information of the measured object can be obtained by analyzing the speckle field. [0003] Laser speckle is a random interference phenomenon, which needs to be studied using statistical methods. Among the statistical characteristic analysis methods of speckle intensity, the speckle contrast imaging method has been widely studied and applied. This method has the advantages of full-field imaging, high temporal resolution and spatial resolution, and has be...

AI Technical Summary

Problems solved by technology

For a specific imaging system, the most direct way to change the speckle size is to change the imaging distance or reduce the size of the scattering exit pupil [W. Lauterborn, etc., Coherent Optics, Springer-Verlag Press, 1993, pages: 80-82], but in a specific imaging system, the adjustment range of these two methods is limited, and sometimes it cannot meet the requirement that the speckle size is larger than two pixels of the CCD camera

[0006] It can be seen from the analysis that in the speckle contrast imaging measurement method, there is still a lack of a speckle contrast imaging measurement device and method that is simple in principle and easy to operate and can change the size of the speckle in a wide range

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