Optical surface preservation techniques and apparatus

Abstract

Techniques and architecture are disclosed for preserving optical surfaces (e.g., windows, coatings, etc.) in a flowing gas amplifier laser system, such as a diode-pumped alkali laser (DPAL) system. In some instances, the disclosed techniques/architecture can be used, for example, to protect optical surfaces in a DPAL system from: (1) chemical attack by pump-bleached alkali vapor atoms and/or ions; and/or (2) fouling by adherence thereto of reaction products/soot produced in the DPAL. Also, in some instances, the disclosed techniques/architecture can be used to substantially match the geometry of the pumping volume with that of the lasing volume, thereby minimizing or otherwise reducing the effects of amplified spontaneous emission (ASE) on DPAL output power. Furthermore, in some cases, the disclosed techniques/architecture can be used to provide a DPAL system capable of producing a beam output power in the range of about 20 kW to 10 MW, or greater.

What is claimed is: 
     
         1 . A diode-pumped alkali laser (DPAL) comprising:
 an optical surface;   a flow of a lasing gas, wherein the lasing gas includes alkali vapor; and   a flow of a first non-alkali gas flowing between the optical surface and the flow of the lasing gas.   
     
     
         2 . The DPAL of  claim 1 , wherein the flow of the first non-alkali gas forms a protective layer along the optical surface to prevent or minimize at least one of chemical attack thereto and/or soot buildup thereon. 
     
     
         3 . The DPAL of  claim 1 , wherein the first non-alkali gas comprises at least one of an inert gas, a noble gas, a hydrocarbon, a fluorocarbon, and/or a combination of any thereof. 
     
     
         4 . The DPAL of  claim 1  further comprising a flow of a second non-alkali gas flowing between the optical surface and the flow of the first non-alkali gas. 
     
     
         5 . The DPAL of  claim 4 , wherein the flow of the second non-alkali gas forms a protective layer along the optical surface to prevent or minimize at least one of chemical attack thereto and/or soot buildup thereon. 
     
     
         6 . The DPAL of  claim 4 , wherein the second non-alkali gas comprises at least one of an inert gas, a noble gas, a hydrocarbon, a fluorocarbon, and/or a combination of any thereof. 
     
     
         7 . The DPAL of  claim 1 , wherein the alkali vapor comprises at least one of rubidium (Rb), cesium (Cs), and/or potassium (K). 
     
     
         8 . The DPAL of  claim 1 , wherein the optical surface comprises an optical window or a mirror. 
     
     
         9 . The DPAL of  claim 8 , wherein the optical surface further comprises an optical coating.