Patent ID: 8889251

Claim:
A multilayer dielectric coating, the coating comprising: more than two alternating layers of high and low index dielectric materials disposed upon a window or a reflector of an alkali laser, wherein an innermost layer of the more than two alternating layers of high and low index dielectric materials comprises at least one of: alumina, zirconia, and hafnia for protecting subsequent layers of the more than two alternating layers of high and low index dielectric materials from alkali attack, wherein the more than two alternating layers of high and low index dielectric materials comprises at least one of: one or more anti-reflection (AR) layers that produce reflectances of less than about 5% at an angle of incidence for a laser beam having a wavelength of between about 650 nm and about 900 nm; and one or more high reflection (HR) layers for pump light for alkali laser wave guide walls, wherein the HR layers produce reflectances of greater than about 98% at a pump wavelength of about 780 nm having an angle of incidence of between about 50° and about 90°, and wherein the innermost layer is a layer configured to be in direct contact with an alkali vapor on an alkali-contacting side of the multilayer dielectric coating.