Spiral Phase Plate (Vortex)

A spiral phase plate converts a Gaussian input profile into a donut-shaped energy ring with zero energy at the center. The spiral phase plate is a unique optic, whose structure is composed entirely of spiral or helical phase steps, whose purpose is to control the phase of the transmitted beam.

The topological charge, denoted in the literature as m, refers to the number of 2π cycles (i.e. “staircases”) etched around 360° turn of diffractive surface. One main effect of a higher topological charge is an increase in the angular momentum of the vortex beam by a factor of m. Another effect is the dimensions magnification of the ring intensity pattern, by a factor of m.

Vortex phase plates are often used in accurate material processing applications with single mode lasers, where a small diameter ring shape is required. See our standard glass Vortex products. For Multi Mode laser or very large ring diameter, we generally recommend to use our Diffractive Axicon.

Other typical applications for Vortex phase plate include  advanced microscopy applications such as STED Microscopy and laser tweezing. For these applications HOLO/OR developed a cost effective vortex generator. See below table for details.