The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 01, 1994
Filed:
Jan. 17, 1992
Richard L Herbst, Palo Alto, CA (US);
Spectra Physics Lasers, Inc., Mountain View, CA (US);
Abstract
A multi-layer graded reflectivity mirror (GRM) with high effective reflectivity is suitable for use in large aperture laser systems with relatively low gain. The GRMs are manufactured with multiple dielectric layers with a thickness profile that eliminates the interference fringes, while providing a reflectivity which tapers smoothly from a peak to zero. The mirror is formed on a substrate having a first surface and a second surface opposite the first. The substrate consists of a material which has low absorption at a given wavelength .lambda.. A first dielectric layer is formed on the first surface of the substrate which has an index of refraction n.sub.1 and having an optical thickness profile with a maximum optical thickness of .lambda./4 at a center which essentially continuously decreases away from the center to a minimum optical thickness of Z at a perimeter P. A second dielectric layer is formed on the first dielectric layer having an index of refraction n.sub.2 and a thickness profile which is similar to the thickness profile of the first dielectric layer. Additional dielectric layers can be added as necessary to achieve the reflectivity magnitude desired. The thickness Z is the thickness at which the reflectivity profile reaches zero at the first interference fringe.