title: Correlation matching method for high-precision position detection of optical vortex using Shack-Hartmann wavefront sensor.
abstract: We propose a new method for realizing high-spatial-resolution detection of singularity points in optical vortex beams. The method uses a Shack-Hartmann wavefront sensor (SHWS) to record a Hartmanngram. A map of evaluation values related to phase slope is then calculated from the Hartmanngram. The position of an optical vortex is determined by comparing the map with reference maps that are calculated from numerically created spiral phases having various positions. Optical experiments were carried out to verify the method. We displayed various spiral phase distribution patterns on a phase-only spatial light modulator and measured the resulting singularity point using the proposed method. The results showed good linearity in detecting the position of singularity points. The RMS error of the measured position of the singularity point was approximately 0.056, in units normalized to the lens size of the lenslet array used in the SHWS.
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, Zhejiang, China. hcx1231@gmail.com
authors.forename: Chenxi
authors.initials: C
authors.lastname: Huang
authors.forename: Hongxin
authors.initials: H
authors.lastname: Huang
authors.forename: Haruyoshi
authors.initials: H
authors.lastname: Toyoda
authors.forename: Takashi
authors.initials: T
authors.lastname: Inoue
authors.forename: Huafeng
authors.initials: H
authors.lastname: Liu
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008027:Light; D010783:Photometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D014159:Transducers