Abstract

We have developed a frequency quadrupled Nd.Yl.F laser as a source of photons to Compton backscatter from a beam of electrons circulating in a storage ring. The laser beam must be transported 22 meters to the interaction region in the synchrotron and the mode at that point must be matched to the electron beam. Unfortunately, the laser is non-Gaussian, so that both the phase and intensity must be known to calculate the beam propagation. The Gerchberg-Saxton phase retrieval procedure² deduces the phase of an image from intensity measurements in the image plane and the diffraction plane. For a freely propagating non-TEM₀₀ beam it is generally difficult to locate the waist.

© 2001 Optical Society of America