Optical coatings for reflecting radiation of longer wavelength visible and having an incident angle grazing

摘要

(57) a reflector coated with a high rate reflects radiation with two different wavelengths of the incident angle of a wide range of incidence angles, including grazing [Abstract]. Reflector is coated, can be used as a waveguide device for laser radiation used, such as combination laser beam ₂ and CO HeNe, the application of medical and other. Preferably, includes a metal substrate (10), multi-layer body is provided on the metal substrate (20), the reflector is coated, the high and low refractive index plurality of alternating multilayers (20) incident short (ie, visible) each pair of dielectric layers of high and low refractive index consists of (21, 22, 23) a dielectric layer, adjacent the multi-layer body (20), the coefficient M / 2 the wavelength has a thickness consistent optically combined substantially equal to a value obtained by multiplying a, equal to (2N-1) λ _L / 8 substantially, the total thickness consistent optical multilayer body (20) in this case , a positive integer, long wavelength incident M and N (for example, the wavelength of the CO ₂ laser beam) is λ _L. Preferably, silver (10) substrate, a high refractive index dielectric material is zinc sulfide, low refractive index dielectric material is cerium fluoride or yttrium fluoride. In another embodiment, the invention is a hollow waveguide device formed by bending polygonal substrates coated flat. Since the bending fold instead of roll forming into a cylindrical coated substrate, the stress is concentrated (32) corner of the polygon rather than being distributed to the presence element of the wave bending unit occurring in the coating. The coating may result in cracks in the corners of the polygonal cross section of the waveguide device, but unaffected in the flat surface between the corners, and cracks in corners come trouble substantial function of the waveguide device not be.