Implementation of an Interferometric System for Generation of Cylindrical Vector-beams Using a Parallel-Aligned Spatial Light Modulator

We document the implementation and improvement of an interferometric system for generation of cylindrical vector beams. The system uses a phase-only spatial light modulator (SLM) which is able to perform multiphase modulation of the beam wavefront by displaying customized forms. A number of separate steps were performed in order to assembly the system and test the method.

This document intends to be a reference detailing the process of implementation of the system from scratch, including convenient modifications to it, which was the core of the work. Furthermore, the feasibility to operate with this kind of setup has been examined and the most critical issues have been addressed. The method has proven to be very flexible by allowing easy switching between vector beams without further changes of the hardware. The generation of higher order modes on demand, which stands as one of the most attractive features of this method, is also realized.

By reviewing recent literature on several aspects of beam structuring, particularly polarization tailored light generation, as well as perspectives for optimization of the chosen method, we have attempted to put the technical dimension of the contribution presented here in context. Investigation and characterization of the SLM employed have been given special relevance. Additionally, interesting applications of the system have been considered.

We show in particular that the high resolution of the SLM employed, its phase-only modulation ability and the particularities of the design of the interferometric setup implemented, allow for the generation of slightly divergent cylindrical vector beams of any order with high diffraction efficiency without performing aberration corrections of the system.

Furthermore, we discuss in detail how the quality of the results can be immediately improved by correcting aberrations that are caused by the back-panel of the SLM. A precise correction can be performed by the SLM itself using a method that involves a phase retrieval algorithm. A first implementation in this direction has been conducted here. The quality of the correction process is particularly relevant for enhancing the accuracy in the generation of a collimated version of the cylindrical vector beams of higher orders, a demand that in turn is set by the final application in which the beams are employed.

 

Further aspects concerning the features of the cylindrical vector beams generated are examined in detail.