Influence of the edge effects on the properties of unstable resonators

Graded-reflectance mirrors for beam quality control in laser resonators

“…The falloff in thickness in the penumbra region depends on the relative dimensions of d, D, h, and H. The arrangement is simple, but there are not enough parameters for accurate control of the variation in thickness. Although this method has been used for the manufacture of some types of GRM, it does not seem to be suitable for super-Gaussian GRM's of low order and large waist or of high order and small waist.15,' 6 Additional problems encountered during the manufacture of fully shaped GRM's with stationary mask and subtrate are mentioned in Section 4. (Fig.…”

“…Over two decades ago theoretical studies indicated that soft apertures or variable-reflectance mirrors reduce the detrimental effects of edge diffraction in optical resonators. '- 6 A number of different approaches have been proposed in the past for the implementation of this principle. Of these, the use of graded-reflectance mirrors (GRM's), also known as variable-reflectance mirrors has proved to be the most practical.…”

Near- and far-field laser modes produced by confocal unstable resonators. I. Free-space and saturable gain media

“…According to the analysis developed by Anan'ev and Sherstobitov (1971), as the Fresnel number of the resonator is increased the resultant mode approaches the limit of uniform distribution, as predicted by geometrical analysis. This results from the relative decrease in the annular area at the edge of the mirrors over which the effective diffraction wave is produced.…”