Measuring device for measuring vortex light beam high-order topological charge

Abstract

A measuring device for measuring vortex light beam high-order topological charge is provide with a He-Ne laser device, wherein collimation and beam expanding devices are sequentially arranged in the light beam advancing direction of the laser device, a spatial light modulator where a forked phase hologram generated by a computer is input generates vortex light beams (shown in the description), and then the vortex light beams pass through a round hole diaphragm and a polarization beam splitter (shown in the description). The vortex light beams (shown in the description) passed through the polarization beam splitter (shown in the description) are divided into transmitting vortex light (shown in the description) and reflecting vortex light (shown in the description), the reflecting vortex light (shown in the description) and the transmitting vortex light (shown in the description) form an included angle of 90 degrees, the reflecting vortex light (shown in the description) advances and then is irradiated onto a reflecting mirror (shown in the description). The reflecting vortex light advances and then passes through a Dove prism to serve as mirror image light beams of the vortex light beams and to be irradiated onto the polarization beam splitter (shown in the description), and the transmitting vortex light (shown in the description) passes through the reflecting mirror (shown in the description) and then serves as the vortex light beams (shown in the description) to be irradiated onto the polarization beam splitter (shown in the description). The vortex light beams (shown in the description) and the mirror image light beams of the vortex light beams pass through the polarization beam splitter (shown in the description) and then are combined to form an interference-superimposed vortex light beam. The interference-superimposed vortex light beam passes through a convergent lens and then enters a CCD camera to be imaged, and then an image is stored in the computer. The device achieves measurement of the vortex light beam high-order topological charge and has the advantages of being simple, quick and accurate.

Description

technical field [0001] The invention relates to a device for measuring high-order topological charges of vortex beams, in particular to a device for measuring high-order topological charges by using an improved Mach-Zehnder interference method. Background technique [0002] The vortex beam has a spiral wavefront and its central light intensity is zero, its expression contains the phase factor of exp(ilθ), each photon carries The orbital angular momentum of , where l is the topological charge. The orbital angular momentum of optical vortex has important applications in optical tweezers, optical wrench, quantum information encoding and other fields. Therefore, the measurement of topological charge is particularly important. After literature retrieval, the paper "Characterizing topological charge of optical vortices by using an annular aperture"【 Opt. Lett. 34 (23), 3686-3688 (2009)], the vortex beam illuminates the aperture diaphragm, and after Fourier transform, the maxi...

AI Technical Summary

Problems solved by technology

The topological charge values ​​measured by these methods are simple and easy to operate, but the measurement range of high-order topological charges is small, and sometimes it is difficult to meet the application requirements.

[0003] It can be seen from the analysis that in the existing public literature, in terms of the measurement method of the high-order topological charge of the vortex beam, the range of the measured topological charge is still small, and there is still a lack of a simple method that can measure a large range of topological charges at the same time. method

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