Generation Of OAM Laser And Detection Of OAM States

Vortex beams carry orbital angular momentum. It is a hot research subject, especiallyin last two years. Vortex beams attract more and more attention to its applications. Thisthesis studied the generation and detection methods of vortex beams, and OAM lasers as adetection method was depicted. There are many ways to detect OAM and this thesis isbased on a spatial light modulator, through designed holographic gratings to achieve thepurpose of increasing measurement range of OAM and simplifying the measurementmethods. This thesis was also related to how to generate a high purity OAM beam andcombine OAM beams. OAM lasers are based on conventional lasers. Mature conventionallasers experience and high-resolution spatial light modulators are prerequisites for theOAM lasers design. This thesis is based on1.645μm Er: YAG laser and HoloeyePLUTO-Telco spatial light modulator to design and simulate OAM lasers.This thesis mainly includes the following parts:1. The research background and development of generating and detecting OAM beamswere briefly introduced.2. A method to generate high purity OAM beam was depicted. Two methods,checkerboard method and blazed grating method, were described to achieve amplitudemodulation using phase-only SLM. At last two methods to combine OAM beams were putforward.3. The simulation results of OAM laser modes using MATLAB software wereintroduced. The threshold, beam size and resonator structure of OAM laser according toEr:YAG crystal were designed.4. Dammann vortex gratings designed by numerical solution of binary-phase gratingswere generated and the topological charge detection range from-12to+12was achieved.The holograms of spiral phase plate and lens were loaded onto the Damman gratings toachieve a vortex beam generation, transformation and detection.