Optical coatings including buffer layers

Abstract

An optics system component has a stainable glass substrate, an optical coating comprising alternating layers of dielectric materials, and a buffer layer positioned on the stainable glass substrate between the substrate and the optical coating. The buffer layer comprises a dielectric material and has a thickness of less than about 20 nm.

What is claimed is: 
     
         1 . An optics system component comprising:
 a stainable glass substrate;   an optical coating comprising alternating layers of first and second dielectric materials; and   a buffer layer positioned on the stainable glass substrate between the substrate and the optical coating, wherein the buffer layer comprises a third dielectric material and has a thickness of less than about 20 nm.   
     
     
         2 . The optics system component of  claim 1 , wherein the stainable glass substrate comprises at least one fluoride and the optics system component is configured as an optical lens. 
     
     
         3 . The optics system component of  claim 1 , wherein the buffer layer comprises SiO 2  and the buffer layer has a thickness of between about 5 nm and about 15 nm. 
     
     
         4 . The optics system component of  claim 3 , wherein the stainable glass with the buffer layer and the optical coating has a transmittance loss of the electromagnetic radiation of less than about 0.2% over an electromagnetic wavelength of about 400 nm to about 900 nm. 
     
     
         5 . The optics system component of  claim 1 , wherein the optical coating comprises alternating layers of SiO 2  and at least one of Ta 2 O 5 , Nb 2 O 5 , TiO 2 , and HfO 2 . 
     
     
         6 . The optics system component of  claim 1 , wherein the glass substrate has a melting temperature of less than about 500° C. 
     
     
         7 . A method of forming an optical system component, comprising the steps of:
 providing a glass substrate comprising one or more fluorides, the glass substrate having a thermal damage threshold;   depositing a first portion of a first layer of an optical coating via plasma deposition on the glass substrate at a first plasma bias voltage;   depositing a second portion of the first layer of the optical coating via plasma deposition on the first portion at a second plasma bias voltage, wherein the second plasma bias voltage is greater than the first plasma bias voltage; and   depositing a second layer of the optical coating on the first layer.   
     
     
         8 . The method of  claim 7 , wherein the thermal damage threshold of the glass substrate is less than about 500° C. 
     
     
         9 . The method of  claim 8 , wherein the first plasma bias voltage is between about 50 V and about 90 V. 
     
     
         10 . The method of  claim 7 , wherein the first layer comprises a material having a refractive index greater than about 2.0. 
     
     
         11 . The method of  claim 7 , wherein the first portion has a thickness between about 5 nm and about 10 nm and the overall thickness of the first layer is greater than about 20 nm. 
     
     
         12 . The method of  claim 11 , wherein the first portion and second portion of the first layer comprise a same dielectric material. 
     
     
         13 . The method of  claim 7 , wherein the optical coating comprises layers of alternating dielectric materials, the first layer comprising at least one of Ta 2 O 5 , Nb 2 O 5 , TiO 2 , and HfO 2 , and the second layer comprising SiO 2 . 
     
     
         14 . The method of  claim 7 , wherein the glass substrate with the optical coating has a transmittance loss of the electromagnetic radiation of less than about 0.1% over an electromagnetic wavelength of about 350 nm to about 800 nm. 
     
     
         15 . A method of forming an optical coating, comprising the steps:
 providing a glass substrate;   depositing a buffer layer on the substrate via plasma deposition at a first plasma bias voltage; and   depositing at least one layer of an optical coating on the buffer layer via plasma deposition, the deposition of the optical coating carried out at a second plasma bias voltage,   wherein the second plasma bias voltage is greater than the first plasma bias voltage.   
     
     
         16 . The method of forming an optical coating of  claim 15 , wherein the first plasma bias voltage ranges from about 50 V to about 90 V and the second plasma bias voltage ranges from about 100 V to about 140 V. 
     
     
         17 . The method of forming an optical coating of  claim 16 , wherein the glass substrate comprises at least one fluoride. 
     
     
         18 . The method of forming an optical coating of  claim 17 , wherein the buffer layer has a packing density greater than about 94%. 
     
     
         19 . The method of forming an optical coating of  claim 18 , wherein at least one of the buffer layer and the optical coating layers has a non-uniform thickness across the glass substrate. 
     
     
         20 . The method of forming an optical coating of  claim 19 , wherein the buffer layer and the at least one layer of the optical coating comprise the same material.