Broadband thermal optical limiter for the protection of eyes and sensors

Abstract

A broadband thermal optical limiter for protecting a light-sensitive object from intense laser beams at all near ultraviolet, visible and near infrared wavelengths is disclosed. The broadband thermal optical limiter comprises: a sample cell containing a solution of broadband absorber material dissolved in a thermal solvent; and a first optical device for converging an incident laser beam into the sample cell. The sample cell is responsive to a converged incident laser beam below a predetermined intensity level for passing therethrough the converged incident laser beam below the predetermined intensity level. The sample cell is also responsive to a converged incident laser beam at or above a predetermined intensity level for thermally defocusing substantially all of the converged incident laser beam in different directions and passing therethrough only a remaining small portion of the converged incident laser beam at or above the predetermined intensity level. The broadband thermal optical limiter further includes a second optical device for focusing substantially all of the laser beam passing through the sample cell into the light-sensitive object to be protected. A collecting aperture may be disposed in front of the second optical device for substantially blocking all light deflected by the protective element and passing therethrough into the second optical device only a small portion of the focused incident light beam at or above the predetermined intensity level.

Dependencies are inferred from the claim text.