Patent ID: 6806039
Filing Date: 2004-10-19
Classification: G02B,G03F

Abstract:
A Method of making a mixed fluoride crystal optical element blank for less than 200 nm wavelength optics, said method including:providing a calcium strontium fluoride crystal feedstock mixture, providing a mixed calcium strontium fluoride oriented crystal seed of CaxSr(1âˆ’x)F2 with x in the range from 0.1 to 0.9, providing a calcium strontium fluoride crystal growth crucible having a mixed crystal growth chamber and a mixed calcium strontium seed crystal orientation receiver for receiving and orienting a mixed calcium strontium seed crystal in relation to said crystal growth chamber, loading said mixed calcium strontium fluoride oriented crystal seed into said seed crystal receiver, loading said calcium strontium fluoride crystal feedstock mixture into said calcium strontium fluoride crystal growth crucible, melting said calcium strontium fluoride crystal feedstock mixture and an upper portion of said mixed calcium strontium fluoride oriented crystal seed, progressively moving said mixed calcium strontium fluoride oriented crystal seed, said melted upper portion of said mixed calcium strontium fluoride oriented crystal seed, and said melted calcium strontium fluoride crystal feedstock mixture trough a crystal growth temperature gradient to grow a seeded oriented calcium strontium fluoride crystal of CaxSr(1âˆ’x)F2 with x in the range from 0.1 to 0.9.