Minimizing spatial-dispersion-induced birefringence

US7163649B2 · kind B2 · utility

Assignee

• Government of the United States of America, as represented by the Secretary of Commerce · US

Inventors

• John H. Burnett · Washington, US
• Zachary H. Levine · Gaithersburg, US
• Eric Shirley · Orange, US

Key dates

• Filing date: Jul 9, 2002
• Grant date: Jan 16, 2007
• Expiry date: Jul 5, 2024

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01P2006/60
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A composition formed from Group II fluorides in which the composition has little or no intrinsic birefringence at a selected wavelength. The composition is a mixed solid solution of CaF2 with a second crystal of SrF2 or BaF2. The resulting composition is in the form of Ca1−xSrxF2 or Ca1−xBaxF2, or a combination of SrF2 and BaF2, in the form of Ca1−x−ySrxBayF2. The specific form of the composition that effectively nulls out the intrinsic birefringence at a selected wavelength within the UV range is determined in one preferred method from the magnitudes of the intrinsic birefringences of the components, CaF2, SrF2, and BaF2.