Hollow waveguide having plural layer dielectric

Claim 2

1 . A narrow diameter, flexible hollow waveguide for high efficiency transmission of laser light by internal reflection, said waveguide comprising: (a) a hollow flexible elongated housing; (b) a metallic coating, highly reflective at normal incidence, on the internal surface of said guide; c) plural layers of thin film dielectric coatings overlying said reflective coatings.

Claim 3

A waveguide as described in Claim 1 and comprising three said layers of dielectric, first and third ones of which being a first select dielectric material, and a middle one of which being a second select dielectirc material.

Claim 4

A waveguide as described in Claim 2 wherein said first select dielectric material has an index of refraction which is relatively low in comparison with the index of refraction of said second select dielectric material.

Claim 5

The hollow waveguide according to Claim 2 wherein the first and third layers are ThP 4 and the second layer is selected from the group consisting of ZnSe and Ge.

Claim 6

The hollow waveguide according to Claim 2 wherein the first and third layers are ZnSe and the second coating is Ge.

Claim 7

The hollow waveguide according to Claim 2 wherein said first and third layers are Ge and the second layer is ThF 4 .

Claim 8

A waveguide as described in Claim 2 wherein said outermost of said dielectric layers has a thickness between approximately one-eighth and three-eights of the wavelength of light in said outermost layer.

Claim 9

A flexible hollow waveguide for high efficiency transmission of C0 2 laser light which comprises: (a) a guide having an internal surface and an external cross section sufficiently small to allow for endoscopic application; (b) a metal coating applied to the internal surface of said metal guide, said coating characterized by a high degree of reflectivity of light at normal incidence for the waveglength of use.; (c) a plural layer dielectric coating applied to said metal coating, said coating composite having the reflectivities of the P and S polarization averaged together to be in excess of 98.5% for all angles of incidence ranging from 80° to 90°.

Claim 10

A flexible hollow waveguide for high efficiency transmission of C0 2 laser light which comprises: (a) a guide having an internal surface and an external cross section sufficiently small to allow for endoscopic application; (b) a metal coating applied to the internal surface of said metal guide, said coating characterized by a high degree of reflectivity of light at normal incidence for the waveglength of use.; (c) a plural layer dielectric coating applied to said metal coating, said coating composite having the reflectivities of the P and S polarization averaged together to be in excess of 98.5% for all angles of incidence ranging from 80° to 90°.

Claim 11

The hollow waveguide according to Claim 8 wherein said guide is made of aluminum and said metal coating is silver.

Claim 12

The hollow metal waveguide according to Claim 8 wherein the interior cross section of the waveguide is square shaped.

Claim 13

The hollow metal waveguide according to Claim 8 wherein the interior cross section of the waveguide is circular.

Claim 14

For use with a laser providing output laser radiation of a given frequency, a waveguide as claimed in any of claims 1 to 11.