Electrically-Reduced Lithium Tantalate Compositions

Abstract

According to some embodiments, a pre-poled, single-domain body of a ferroelectric crystalline material such as lithium tantalate or lithium niobate is electrically reduced by applying a voltage across the body in a non-oxidizing environment while the body is heated to a process temperature below its Curie temperature. The voltage generates an electric field along the polar axis of the body. Electrodes may be formed on the body surface by applying an acetate-based silver paint. Exemplary methods allow achieving lithium tantalate electrical conductivity values of 10 −11 to 10 −9 Siemens/cm and average optical absorption values greater than 50% per 0.4 mm thickness at wavelengths of 300 nm and 460 nm.

1 . A composition comprising a substantially single-domain, electrically-reduced body of lithium tantalate, wherein:
 an average optical absorption of the body is greater than 50% per 0.4 mm thickness at a wavelength of 300 nm; and   the average optical absorption of the body is greater than 50% per 0.4 mm thickness at a wavelength of 460 nm.   
   
   
       2 . The composition of  claim 1 , wherein the optical absorption of the body is substantially greater at 460 nm than at 350 nm. 
   
   
       3 . The composition of  claim 1 , wherein the average optical absorption of the body has a value between 60% and 80% per 0.4 mm thickness at the wavelength of 300 nm. 
   
   
       4 . The composition of  claim 3 , wherein the average optical absorption of the body has a value between 60% and 80% per 0.4 mm thickness at the wavelength of 460 nm. 
   
   
       5 . A composition comprising a substantially single-domain, electrically-reduced body of lithium tantalate having an average electrical conductivity higher than about 10 −11  Siemens/cm. 
   
   
       6 . The composition of  claim 5 , wherein the electrical conductivity is lower than about 10 −9  Siemens/cm.