We are investigating the formation and propagation of optical vortex beams
created with an ℓ = 1-8 spiral phase plate (RPC Photonics,
Rochester). Illuminating the plate with an annular apodized wavefront
produced by Fresnel diffraction should improve the quality of the
vortex beams, making them closer to pure LG modes.
Supported by the Stony Brook Laser Teaching Center.