Abstract Room temperature use of LiNb03 in devices involving transmission of coherent radiation has been restricted by the observation that the material ''''damages'''' in relatively short periods at commonly used intensity levels. Such damage takes the form of the development of local refractive index inhomogeneities which scatter the radiation. Such damage is reduced to a level sufficient to permit use of LiNb03 in any such device at room temperature by maintenance of the concentration level of Fe2 impurity at less than 10 ppm and by annealing at temperatures below 700* C. In a preferred embodiment, at least a portion of such said annealing is carried out with the sample under the influence of an imposed electric field.
Device of claim 1 in which at least one of said means comprises an optically polished surface and in which the device is designed such that the extracted beam comprises radiation having a wavelength below about 0.65 micrometer.
Claim 2
Dependent Claim
28 words
Device of claim 2 in which the said second means is designed for extracting a beam containing radiation of a wavelength not included within the said first means.
Claim 3
Dependent Claim
14 words
Device of claim 3 designed for operation at a temperature below about 100* C.
Claim 4
Dependent Claim
30 words
Device of claim 4 designed for operation as a second harmonic generator so that the said radiation has a wavelength half that of the beam associated with the first means.
Claim 5
Dependent Claim
33 words
Device of claim 4 designed for operation as a parametric device of such nature that the said radiation has a wavelength greater than that of the beam associated with the said first means.
Claim 6
Dependent Claim
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Device of claim 6 provided with means for supporting said radiation, said supporting means consisting essentially of a resonant cavity which includes a focusing means for focusing said electromagnetic radiation within said supporting means.
Claim 7
Dependent Claim
30 words
Device of claim 1 in which said process includes the step of annealing said crystalline material in an oxidizing oxygen-containing atmosphere within the temperature range of from 500*C to 700*C.
Claim 8
Dependent Claim
57 words
Device of claim 8 in which said annealing comprises maintenance of the said crystalline material within the said temperature range for a period of at least 5 minutes while applying an electric field across the said material, said field being sufficient to produce a current density of at least 1 milliampere per square centimeter of cross section.