Intracavity mode competition between classes of flat-top beams
Date
2008
Authors
Litvin I.
Loveday P.W.
Long C.S.
Kazak N.S.
Belyi V.
Forbes A.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
There are many applications in which a laser beam with a flat-top intensity profile would be ideal, as compared to a laser beam with a non-uniform energy distribution. Standard stable optical resonators will unfortunately not generate such a laser beam as the oscillating mode. Single-mode oscillation would typically be Gaussian in profile, while multimode oscillation might deliver a beam with an averaged flat-like profile in the near field, but would diverge very quickly due to the higher order modes, in addition, if the modes are coherently coupled, then large intensity oscillations could be expected across the beam. Techniques exist to generate flat-top beams external to the cavity, but this is usually at the expense of energy, and almost always requires very precise input beam parameters. In this paper we present the design of an optical resonator that produces as the stable transverse mode a flat-top laser beam, by making use of an intra-cavity diffractive mirror. We consider the modal build-up in such a resonator and compare the mode competition between flat-top like beams, including Flattened Gaussian beams, Fermi-Dirac beams, and super-Gaussian beams. Finally, we remark on the use of an intra-cavity piezoelectric unimorph mirror for selecting a particular class of flat-top beam as the fundamental mode of the resonator.
Description
Keywords
Acoustooptical effects, Competition, Gaussian noise (electronic), Ion beams, Laser beams, Laser resonators, Mirrors, Optical resonators, Piezoelectric transducers, Piezoelectricity, Trellis codes, Beam parameters, Diffractive mirrors, Energy distributions, Fermi-Dirac, Flat tops, Flat-top beams, Fundamental modes, Gaussian, Higher-order modes, Intensity oscillations, Intensity profiles, Intra cavities, Mode competitions, Multi-mode oscillations, Near fields, Non-uniform, Oscillating modes, Piezoelectric unimorph mirror, Resonator modes, Single-mode oscillations, Super-Gaussian, Transverse modes, Gaussian beams
Citation
Proceedings of SPIE - The International Society for Optical Engineering
7062
7062