title: Analysis of multilevel spiral phase plates using a Dammann vortex sensing grating.
abstract: Optical vortices can be easily generated using a multilevel spiral phase plate (SPP). However the quality of the generated vortex beam depends on the number of phase segments. We review the theory for this multilevel SPP using a Fourier expansion of integer topological charged vortices. We then experimentally examine the validity of this expansion using a fabricated Dammann vortex diffraction grating spectrum analyzer. The Dammann vortex diffraction grating is fabricated using SU-8 photoresist on glass substrate and yields uniform diffraction efficiency across a desired number of diffracted orders. Experimental results show the extra angular harmonics of a multilevel SPP and agree with the theory.
authors.affiliation: School of Electrical & Electronic Engineering, Nanyang Technological University, 639798 Singapore.
authors.forename: N
authors.initials: N
authors.lastname: Zhang
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Davis
authors.forename: Ignacio
authors.initials: I
authors.lastname: Moreno
authors.forename: Don M
authors.initials: DM
authors.lastname: Cottrell
authors.forename: X-C
authors.initials: XC
authors.lastname: Yuan
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008962:Models, Theoretical; D055096:Optical Devices; D012031:Refractometry / Q000295:instrumentation*; D014159:Transducers