Optical field spin angle momentum measuring device and method

Abstract

The invention relates to the technical field of optical measurement, in particular to an optical field spin angle momentum measuring device and method. The optical field spin angle momentum measuringdevice is used for collecting and obtaining a transverse component of a light field through a signal collecting unit; a spin detection unit is used for obtaining a left-handed polarization component and a right-handed polarization component through extraction; a photoelectric conversion unit is used for obtaining a voltage signal corresponding to the left-handed polarization component and a voltage signal corresponding to the right-handed polarization component through conversion; a data acquisition unit obtains a digital signal corresponding to the left-handed polarization component and a digital signal corresponding to the right-handed polarization component through conversion; and a spin angle momentum calculation module carries out calculation based on the digital signal correspondingto the left-handed polarization component and the digital signal corresponding to the right-handed polarization component to obtain the spin angle momentum of the light field. The extraction method issimple, complex measurement and calculation processes are avoided, and the calculation efficiency of the spin angle momentum of the light field is improved.

Description

technical field [0001] The invention relates to the technical field of optical measurement, in particular to an optical field spin angular momentum measurement device and method. Background technique [0002] Angular momentum plays an important role in the interaction between light and matter, and it can generally be divided into spin angular momentum and orbital angular momentum. The spin angular momentum depends on the polarization state of the light field, for example, left-handed circularly polarized light and right-handed circularly polarized light have different spin angular momentum; the orbital angular momentum is related to the specific spatial phase distribution of the light field, such as a vortex with a helical phase factor Optical field. Generally, the spin angular momentum and orbital angular momentum of light field in free space are considered as two independent degrees of freedom, but in non-homogeneous space light fields such as surface plasmon photonics an...

AI Technical Summary

Problems solved by technology

At present, there are mainly the following methods for measuring the spin angular momentum of the light field: 1. Using the reconstruction algorithm of meter scattering nano-interference, measuring the interference signals of the scattered light of the nanosphere particles and the incident light at different angles to obtain the angular spectrum distribution , and then reconstruct and calculate the magnitude and phase of the light field, and finally calculate the spatial distribution of its spin angular momentum. This method can obtain complete light field information, but requires complex measurement and calculation processes; 2. A The method of directly measuring the dynamic characteristics of the light field is to use optomechanics to obtain the spin angular momentum distribution information of the light field by measuring the force and moment of the scattering particles in the light field. This measurement method is difficult and only The momentum and angular momentum in several specific directions can be obtained; 3. Measure the light intensity distribution in different directions of the scattered light of nanoparticles in the tightly focused vector light field, and finally obtain the transverse spin angular momentum distribution of the light field

These methods of measuring the spin angular momentum of the light field basically involve complex reconstruction calculations and are difficult to experiment.

Images