Electro-optic and electrical properties in Hafnium-doped congruent lithium-niobate crystals

Surface domain engineering in congruent lithium niobate single crystals: A route to submicron periodic poling

We describe a technique for surface domain engineering in congruent lithium niobate single crystals. The method is based on conventional electric-field poling, but involves an intentional overpoling step that inverts all the material apart from a thin surface region directly below the patterned photoresist. The surface poled structures show good domain uniformity, and the technique has so far been applied to produce domain periods as small as 1 μm. The technique is fully compatible with nonlinear optical integrated devices based on waveguide structures.

Anisotropic model for the fabrication of Annealed and Reverse Proton Exchanged waveguides in congruent Lithium Niobate

An anisotropic model for the fabrication of annealed and reverse proton exchange waveguides in lithium niobate is presented. We characterized the anisotropic diffusion properties of proton exchange, annealing and reverse proton exchange in Z-cut and X-cut substrates using planar waveguides. Using this model we fabricated high quality channel waveguides with propagation losses as low as 0.086 dB/cm and a coupling efficiency with optical fiber of 90% at 1550 nm. The splitting ratio of a set of directional couplers is predicted with an accuracy of +- 0.06.

Continuous-wave backward frequency doubling in periodically poled lithium niobate

We report on backward second-harmonic-generation in bulk periodically poled congruent lithium niobate with a 3.2 microns period. A tunable continuous-wave Ti:sapphire laser allowed us exciting two resonant quasi-phase-matching orders in the backward configuration. The resonances were also resolved by temperature tuning and interpolated with standard theory to extract relevant information on the sample.

铌酸锂与钽酸锂材料体系中光学带隙的温度依赖性

On the temperature dependence of the optical band gap in the material system of lithium niobate and lithium tantalate

研究铌酸锂与钽酸锂的光学带隙温度依赖性，揭示其带隙差异源于电子-声子耦合与声子能量，开发PhoQS-Treat软件，推动铌酸锂基器件发展

Experimental observation of internally-pumped parametric oscillation and quadratic comb generation in a $χ^{(2)}$ whispering-gallery-mode microresonator

We report on the experimental observation of internally-pumped parametric oscillation in a high-Q lithium niobate microresonator under conditions of natural phase-matching. Specifically, launching near-infrared pump light around 1060 nm into a $z$-cut congruent lithium niobate microresonator, we observe the generation of optical sidebands around the input pump under conditions where second-harmonic generation is close to natural phase-matching. We find that a wide range of different sideband frequency shifts can be generated by varying the experimental parameters. Under particular conditions, …