Achievement of large-sized TEM_00 mode from an excimer laser by means of a novel apoditic filter

We describe a novel apoditic filter characterized by a near-Gaussian transmission function and capable of operating in high-power lasers. By using this filter within the telescopic cavity of a XeCl laser we have obtained a laser output beam with a near-Gaussian intensity distribution. The achieved beam size is comparable with and the beam quality is superior to those achievable with an equivalent diffractive unstable cavity.