A detection device and detection method for beam orbital angular momentum value

Abstract

The invention discloses a detection device and method for the orbital angular momentum value. The detection device comprises a half wave plate, a spatial light modulator, a focusing lens and a CCD camera which are sequentially arranged along the light beam propagation route. The spatial light modulator and the CCD camera are both connected with a computer. According to the detection method, the orbital angular momentum value of an incidence spiral light beam is obtained by observing the position of a Gaussian hot spot in a far-field diffraction pattern and judging the diffraction level where the Gaussian light beam is located. The detection device has the advantages of being simple in structure and capable of conveniently conducting detection.

Description

technical field [0001] The invention belongs to the field of optoelectronic technology, and in particular relates to a detection device and a detection method for the orbital angular momentum value of a light beam. Background technique [0002] A helical beam is a Beams of the form phase factor. Each photon in a helical beam carries orbital angular momentum (where l is the orbital angular momentum value). When l=0, this type of beam is the same as an ordinary Gaussian beam, and when l is not equal to 0, there is a phase singularity in the center of this type of beam and the central intensity of the beam is 0. Since this type of beam has a periodic spiral phase wavefront, it has important application prospects in the fields of beam micromanipulation, biomedicine, nonlinear optics, and optical information transmission. In recent years, research on the generation, detection, transmission and application of helical beams has developed rapidly, and has increasingly become a...

AI Technical Summary

Problems solved by technology

Among these four methods, the first method requires continuous cascading interferometric devices when measuring high-dimensional orbital angular momentum, and the system is complex and huge; the second method requires constant replacement of wave plates, which is also inconvenient for detection; and the third Both the first and fourth methods are extremely difficult to adjust due to the introduction of continuous rotating elements. It can be seen from the combination of these methods that there is still a lack of simple and convenient devices that can detect the value of the orbital angular momentum of the beam.

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