Spatial Profile Flattening of Ultraviolet Laser Pulses with Aspheric Refractive Optics

The performance of an aspheric refractive beam shaping optic is evaluated with 2 picosecond pulses of 263nm wavelength from the drive laser of the SLAC Gun Test Facility radiofrequency photocathode gun. The aspheric optic is designed to convert a transverse radial Gaussian profile input into a transverse radial Fermi-Dirac profile with improved uniformity in the central region. We evaluate the correlated performance of the aspheric optic output subject to input beam position jitter to produce tolerances for input jitter based on photoinjector uniformity requirements. The position jitter tolerance of the aspheric optic is estimated to be 3% of the input beam Gaussian 1/e{sup 2} intensity half width to provide 90% drive laser profile uniformity.