#People were putting their bets on extreme #ultraviolet light, but it would be years before the litho machines in the fabs could muster enough 

#ultraviolet. But because such light couldn’t #pierce existing lenses, it would need an exotic new lens made of calcium fluoride. Researchers built 

 #Ozone #layer  is a  #Sun's #ultraviolet radiation. It  a high concentration of ozone (O3) in relation to other parts of the atmosphere .