Axicons in Action

Abstract

AbstractAxicon lenses convert incident plane waves into approximations of Bessel beams. The circular profile of an axicon beam brings capabilities that suit the lenses for use in corneal surgery and optical trapping. The unique features of axicon lenses also enable an interesting type of wavefront sensor. Axicons focus light along the optical axis, and the position shifts if aberrations are introduced to the beam. That creates variation in the intensity distribution measured by an image sensor. In addition, the center of an axicon lens, the apex, also scatters some of the incident light. The focused light and the scattered light can interfere with each other, creating a self‐referenced interferogram. A wavefront sensor based on an axicon lens can measure low order aberrations with no need for a separate reference wavefront optical train. Wavefront sensors based on axicons offer an inexpensive, rapid, and compact method of detecting small aberrations in the beam.