A device for measuring the topological charge value of fractional optical vortex and its measuring method

Abstract

Provided are a device for measuring fractional-order optical vortex topology charge values and a measuring method thereof. The measuring method comprises the steps of writing generated calculating holographic images into a spatial light modulator through a computer holographic technique, acquiring wrapped phase images of vortex light beams through Michelson interference light paths and a four-step phase shifting technique, analyzing distribution of real phases theta of the vortex light beams through a phase image unwrapping algorithm, and calculating according to the topology charge definition of m=theta / 2pi to obtain topology charge values m of any fractional-order accuracy. The device and method achieve the measurement of any step (0.1 step) of topology charge values of the fractional-order vortex light beams, can correct measurement of topology charge values of vortex light beams from existing half-integer step (0.5 step) to any step and can be widely applied to measurement of topology charge values in the fields of bose-einstein condensation, quantum communication, information coding and transmission, particle confinement, optical tweezers, optical wrenches and the like.

Description

technical field [0001] The invention relates to a device and method for measuring the topological charge value of fractional-order optical vortex, in particular to a device and method for measuring the topological charge value of fractional-order vortex by using phase. Background technique [0002] As the vortex beam has important application prospects in the fields of Bose-Einstein condensate, quantum information coding, particle trapping, optical tweezers and optical wrench, it has become a very important research hotspot in the field of information optics in recent years. In 2004, M.V.Berry systematically and comprehensively expounded the theoretical basis of fractional optical vortex for the first time (M.V.Berry, J Opt a-PureAppl Op 6(2004) 259). Fractional vortex beams can carry more information and provide finer particle manipulation, which has become a hot topic for many researchers in the field of vortex optics. [0003] The most elegant way to generate fractional ...

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Problems solved by technology

But these two methods are realized by measuring the number of interference / diffraction fringes, which can only achieve half-integer order (0.5 order) precision (A.Mourka et al., Optics Express 19(2011)5760) topological charge value measurement

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