Phonon-assisted energy transfer in Er-exchanged LiNbO3

Raman microprobe spectroscopy measurements show, that in contrast to Er-idiffusion, Er-exchange proc- ess leads to significant change of the lattice vibration spectrum of LiNbO3. Therefore, our data allow to assume that the drastic suppression of parasitic upconversion in the Er-exchanged LiNbO3 are caused by multiphonon nonradiative decay of the 2(4F9/2) state, providing fast nonradiative energy transfer to the 4G11/2 and (4F7/2+4I13/2) states

Characterization of alpha-phase soft proton-exchanged LiNbO3 optical waveguides

Waveguides in LiNbO3 are realized by a soft proton exchange (SPE) process with use of a melt of stearic acid highly diluted by lithium stearate. No phase transitions are formed when alpha-phase waveguides are obtained by SPE. The alpha-phase presents the same crystalline structure as that of pure LiNbO3 crystal, and it maintains the excellent nonlinear and electro-optical properties of the bulk material. The kinetics of the SPE method is studied by the use of secondary-ion mass spectrometry and prism-coupling techniques. The hydrogen effec- tive diffusion coefficient as well as the self-diffusion coefficients of H+ and Li+ ions are determined as a func- tion of the proton-exchange temperature for X-cut LiNbO3

Proton-exchanged waveguides in MgO-doped LiNbO3: Optical and structural properties

We show that MgO:HxLi1-xNbO3 single crystalline solid solutions prepared by proton exchange exhibit very complex structural chemistry which is different from that for undoped congruent material. A correlation between the crystal structure and the refractive index profiles has been experimentally determined that allows us to explain specific peculiarities of the optical properties observed, as well as to predict the characteristics of a variety of waveguides. We have established that the well-known annealing proton exchange process leads to crystal structure disorder in MgO:LiNbO3 within the surface region of waveguides fabricated this way, but the soft proton exchange process preserves the crystal structure of magnesium-doped material

Compositional and structural analysis of iron doped X-cut lithium niobate crystals

We present a systematic study on the correlation between the compositional and structural properties of iron doped X-cut lithium niobate crystals doped by the thermal diffusion of thin iron film deposited via radio frequency (RF) sputtering varying the preparation conditions. The iron concentration profiles measured by using secondary ion mass spectrometry were properly fitted to determine the iron diffusion coefficients and the activation energy of the diffusion process. High resolution X-ray diffraction technique was used to study the crystalline quality of the doped region and to estimate the strain induced by the dopant incorporation. Depending on the preparation condition compressive and tensile strains were found in the diffused region

Compositional and structural analysis of iron doped X-cut lithium niobate crystals

We present a systematic study on the correlation between the compositional and structural properties of iron doped X-cut lithium niobate crystals doped by the thermal diffusion of thin iron film deposited via radio frequency (RF) sputtering varying the preparation conditions. The iron concentration profiles measured by using secondary ion mass spectrometry were properly fitted to determine the iron diffusion coefficients and the activation energy of the diffusion process. High resolution X-ray diffraction technique was used to study the crystalline quality of the doped region and to estimate the strain induced by the dopant incorporation. Depending on the preparation condition compressive and tensile strains were found in the diffused region