High repetition rate UV excimer laser

Abstract

The invention relates to an High Repetition Rate UV Excimer Laser which includes a source of a laser beam and one or more windows which include magnesium fluoride. Another aspect of the invention relates to an excimer laser which includes a source of a laser beam, one or more windows which include magnesium fluoride and a source for annealing the one or more windows. Another aspect of the invention relates to a method of producing a predetermined narrow width laser beam.

What is claimed is:  
     
         1 . A method of producing a ≧4 kilohertz repetition rate excimer laser beam comprising: 
 oscillating a laser beam whereby the laser beam exits a first magnesium fluoride crystal window of a chamber and passing the laser beam through a second magnesium fluoride crystal window of the chamber to provide a ≧4 kilohertz repetition rate excimer laser beam.  
 
     
     
         2 . A method as claimed in  claim 1  wherein the ≧4 killohertz repetition rate excimer laser beam has a power of greater than or equal to 10 mJ.  
     
     
         3 . A method as claimed in  claim 1  wherein the magnesium fluoride crystal windows maintain durability over 500 million pulses of the laser beam.  
     
     
         4 . A ≧4 kilohertz repetition rate excimer laser comprising: 
 a ≧4 kilohertz repetition rate excimer laser beam source for producing a ≧4kilohertz repetition rate excimer laser beam and one or more magnesium fluoride crystal windows for transmitting said ≧4 kilohertz repetition rate excimer laser beam.  
 
     
     
         5 . An excimer laser according to  claim 4 , wherein the laser beam has a power of greater than or equal to 10 mJ.  
     
     
         6 . An excimer laser according to  claim 4 , wherein said ≧4 kilohertz repetition rate excimer laser beam source is an argon fluoride excimer laser beam source.  
     
     
         7 . An excimer laser according to  claim 4 , wherein said ≧4 kilohertz repetition rate excimer laser beam source is a krypton fluoride excimer laser beam source.  
     
     
         8 . An excimer laser according to  claim 6  further comprising: a source for annealing the one or more windows.  
     
     
         9 . An excimer laser according to  claim 4  wherein the windows maintain durability over 500 million pulses of the laser beam.  
     
     
         10 . An excimer laser comprising: 
 a source for a laser beam;    one or more windows comprising magnesium fluoride crystal; and a source for annealing the one or more comprising magnesium fluoride crystal windows.    
     
     
         11 . An excimer laser according to  claim 10 , wherein the laser beam has a power of greater than or equal to 10 mJ.  
     
     
         12 . An excimer laser according to  claim 10 , wherein the laser beam has a repetition rate of greater than or equal to 4 KHz.  
     
     
         13 . An excimer laser according to  claim 10 , wherein the laser beam source is argon fluoride.  
     
     
         14 . An excimer laser according to  claim 10 , wherein the laser beam source is krypton fluoride.  
     
     
         15 . An ≧4 kilohertz repetition rate argon fluoride excimer laser window comprising a magnesium fluoride crystal.  
     
     
         16 . A method of producing a predetermined narrow width laser beam comprising: 
 oscillating a laser beam whereby the laser beam exits a first window of a chamber;    widening the laser beam through one or more prisms;    controlling the widened laser beam to a predetermined narrow width; and    passing the predetermined narrow width laser beam through a second window of the chamber, wherein the first and second windows of the chamber are comprised of magnesium fluoride.    
     
     
         17 . A method according to  claim 16 , wherein the laser beam has a power of greater than or equal to 10 mJ.  
     
     
         18 . A method according to  claim 16 , wherein the laser beam has a repetition rate of greater than or equal to 4 KHz.  
     
     
         19 . A method according to  claim 16 , further comprising pulsing the laser beam over 500 million pulses.  
     
     
         20 . A method according to  claim 19 , wherein the first and second window maintain durability.  
     
     
         21 . A method according to  claim 19 , wherein the laser beam is pulsed over 900 million pulses and the first and second window maintain durability.  
     
     
         22 . A method according to  claim 16 , further comprising: 
 annealing the first window.    
     
     
         23 . A method according to  claim 22 , further comprising: 
 annealing the second window.    
     
     
         24 . A method according to  claim 16 , wherein the laser beam source is argon fluoride.  
     
     
         25 . A method according to  claim 16 , wherein the laser beam source is krypton fluoride.