Single-beam interference from plain Gaussian and OAM wavefronts

We implement an SLM to generate laser beams of variable orbital angular momentum, also referred as Laguerre- Gaussian beams. Input beam polarization takes into account a local birefringence of each pixel of the SLM. We identify the beam polarization eigenstates allowing generate L-G beams of different order via matching variable birefringence of every separate pixels. Zero-order beam passing through the SLM can interact with a generated OAM beam to create an interference pattern. Experimental results demonstrate good agreement with simulations.