Lithium niobate single crystal thin film and production method thereof
First Claim
1. A lithium niobate single crystal thin film formed on a lithium tantalate substrate, characterized in that said lithium niobate single crystal thin film is formed on a (0001) surface of said lithium tantalate substrate, the a-axis lattice constant of said lithium niobate single crystal thin film is 99.81 to 100.07% of the a-axis lattice constant of said lithium tantalate substrate, and said lithium niobate single crystal thin film has an optical propagation loss of 1.4 dB/cm or less.
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Abstract
A lithium niobate single crystal thin film formed on a lithium tantalate substrate, in which the a-axis lattice constant of the lithium tantalate substrate and the a-axis lattice constant of the lithium niobate single crystal thin film are lattice matched.
To achieve the lattice matching, the lithium tantalate substrate is contacted with a molten composition to epitaxially grow a lithium niobate single crystal thin film, the molten composition mainly comprising Li2 O, V2 O5, Nb2 O5, Na2 O and MgO, whereby the a-axis lattice constant of the lithium niobate single crystal thin film and the a-axis lattice constant of the lithium tantalate substrate are matched to each other.
With this arrangement, a lithium niobate single crystal thin film with large thickness and low propagation loss can be obtained without poling, which could not be obtained with prior art methods, thus greatly contributing to the optical device industry.
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19 Claims
- 1. A lithium niobate single crystal thin film formed on a lithium tantalate substrate, characterized in that said lithium niobate single crystal thin film is formed on a (0001) surface of said lithium tantalate substrate, the a-axis lattice constant of said lithium niobate single crystal thin film is 99.81 to 100.07% of the a-axis lattice constant of said lithium tantalate substrate, and said lithium niobate single crystal thin film has an optical propagation loss of 1.4 dB/cm or less.
- 10. A method for producing a lithium niobate single crystal thin film comprising contacting a lithium tantalate substrate with a molten composition to epitaxially grow a lithium niobate single crystal thin film, said molten composition comprising Li2 O, V2 O5, Nb2 O5, Na2 O and Mg O, thereby growing said lithium niobate single crystal thin film having an a-axis lattice constant of 99.81 to 100.07% that of said lithium tantalate substrate on a (0001) surface of said lithium tantalate substrate.
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