Spectra-physics Gmbh

Gary W DeBell

David L Wright

Lee R Carlson

Alan B Petersen

Marc K Von Gunten

Kenneth A Ruddock

Robert J Schultz

Mark W Anderson

A method and system for stabilizing the output frequencies of a multimode laser of the type which operates in at least three optical cavity modes includes detecting the intermodulation product frequency, using a suitable photodetector. The optical cavity modes may be either purely longitudinal for a single transverse mode, or may include radiation from multiple transverse cavity excitations, also with possible longitudinal plurality. The detector output is monitored for the intermodulation product beat signal which is contained in the detector current at the differences of the primary difference frequencies of the optical modes. A signal derived from the frequency of the intermodulation product term is compared with a reference signal, and the resulting error signal is driven to zero by varying the optical length of the laser oscillator cavity in response to the error signal, thereby causing the operating modes of the laser to be stabilized. Possible means of adjusting optical cavity length include, but are not limited to, thermal expansion or contraction of the resonator support structure which is used to establish the relative spacing of the laser's end mirrors, by piezoelectric or magnetostrictive means according to which one or both cavity mirrors is moved to change physical cavity length, or other electro-optic means which may be employed to adjust optical cavity length by control of the refractive index or optical path length presented by an intracavity optical element.

Intermodulation product stabilized laser

An optical component of a laser, of the type including a hot gas plasma region, a cold gas region, and producing large photon fluxes, includes an optical element and a coating means on a surface of the optical element exposed to the photon fluxes. The coating means is comprised of a material adapted to minimize photoreduction of the optical element induced by exposure to the photon fluxes. Optical elements of the present invention include windows, birefringent plates, intracavity lenses, polarizers and mirrors. The coating means includes a material selected from the group comprising Al.sub.2 O.sub.3, BeO, Y.sub.2 O.sub.3, MgO, B.sub.2 O.sub.3, Sc.sub.2 O.sub.3, LiF, NdF.sub.3, ThF.sub.4, Na.sub.3 AlF.sub.6, and mixtures thereof.

Optical component of a laser

An optical component of a laser of the type including a hot gas plasma region, a cold gas region and producing large photon fluxed includes an optical element and a coating means on a surface of the optical element exposed to the photon fluxes. The coating means is comprised of a material adapted to minimize photoreduction of the optical element induced by exposure to the photon fluxes. Optical elements of the present invention include windows, birefringent plates, intra-cavity lenses, polarizers and mirrors.

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Los Altos, CA, United States of America

Gary W DeBell