Abstract This article reviews the current knowledge on main properties and applications of hydrogen in LiNbO3. The review is divided into three parts. first devoted to general such as methods defect production control, techniques used for their detection characterization, well interactions with other lattice defects. second part considers central role played by OH- defects fabrication optical waveguides protonexchange method. Conditions exchange process, structure exchanged layers,...

The effect of X-irradiation on the absorption spectra pure and impurity (Cu, Mn, Ni, Eu)-doped LiNbO3 has been systematically investigated. Three main bands with peaks at 1.6, 2.5 3.2 eV have observed in crystals or Mn-, Ni- Eu-doped after low-temperature (10K) irradiation. For Cu-doped samples, a competition is apparent between production these conversion Cu2+ (1.2 band) into Cu+ (3.1 band). From this information thermal annealing behaviour optical together comparison EPR data Schirmer Von...

Illumination is a crucial factor in hyperspectral imaging systems. In this respect, work focused on analyzing the influence of light power source acquiring images. To end, custom regulated supply was designed and developed. This then integrated into acquisition system, several stability measurements were conducted. Finally, parameters related to produced by those systems extracted using image analysis techniques, statistical comparison among different supplies performed. Two commercial also...

A narrow-bandwidth interference filter has been developed using volume holography in photorefractive LiNbO3 crystals. The device works as a Bragg reflector hologram recorded, fixed and sample. With 2 mm thick plate the following performances have achieved: peak reflectivity above 32%, full-width at half-maximum bandwidth below 0.05 nm, an angular field of view about 3 degrees wavelength 518.45 nm (for green Ar laser writing wavelength). These compare well with that exhibited by conventional...

The influence of ${\mathrm{LiNbO}}_{3}$ stoichiometry ([Li]/[Nb] ratio) on a number physical phenomena, related to the presence lattice defects, has been investigated. Positron-lifetime spectra from crystals with different compositions reveal two states for positrons (lifetimes 230 and 250 ps). long-lived state is attributed trapped at cation vacancies, most likely Nb vacancies. Luminescence under x-ray excitation show same main emission band, peaking about 2.9 eV all compositions, although...

Abstract The structural damage induced by ion irradiation on dielectric materials and associated device degradation has been, so far, explained the basis of collisional processes mostly ignoring electronic excitation. Recent work, focused lithium niobate, offers conclusive evidence that at high energy moderate mass ( A ≥ 15) excitation may induce a giant enhancement over rate due to nuclear collisions. As consequence material becomes amorphized fluences far below those required for...

X-ray induced luminescence, photoluminescence and thermoluminescence of nominally pure Bi4Ge3O12 crystals are studied within the 12K-295K temperature range. The broad emission band reported by other workers for radio- is observed to present some structure. spectra exhibit eight major glow peaks whose wavelength a structure similar that radio-and emissions. This discussed in terms Bi3+ intra-ionic transitions.

A new method to determine the proton concentration in LiNbO3 is presented. The based on measurement of diffraction efficiency a photorefractive grating two situations. It first measured after recording at room temperature, and second saturation fixing process given temperature (about 150 °C). From only these experimental data, value obtained for our sample H0=(4.4±0.7)×1018 cm−3. This agrees, within error, with that from infrared absorption arising OH− stretching bond.

A detailed study of optical absorption, excitation, and emission spectra ${\mathrm{Eu}}^{3+}$ in the ${\mathrm{LiNbO}}_{3}$ lattice is presented within 2700--22 000-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ range. The positions crystal-field levels ${C}_{3}$ symmetry are given for $^{7}\mathrm{F}$ multiplet three lowest $^{5}\mathrm{D}$ multiplet. Most observed bands assigned to specific transitions this scheme, a simple estimate parameters given.

The appearance of light intensity thresholds for catastrophic optical damage in LiNbO3 is satisfactorily explained by using a photorefractive model based on the Fe(2+)?Fe(3+) and NbLi(4+)?NbLi(5+) defect pairs. Model simulations amplification gain as function present sharp threshold behavior. A similar behavior shown saturating refractive index change. In agreement with experiments, predicted appear shifted towards higher intensities (up to 10(4) factor) when Nb(Li) concentration decreased...

A method is proposed and demonstrated to fabricate guiding layers on ordinary refractive index in proton exchanged LiNbO3 waveguides. The process consists of performing a reverse exchange melt very rich lithium substrate previously normal benzoic acid. Layers supporting several modes with polarization are easily obtained. Losses for these have been found be below 0.7 dB/cm. Together the increase index, decrease extraordinary one obtained so that buried can guided this polarization. influence...

The thermal and optical stability of photorefractive holograms written in iron-doped LiNbO3 have been measured over the temperature range from 50 to 165 degrees C. In each case decay proceeded as a non-simple exponential process exhibiting several more or less resolvable stages. For optically erased activation energy two observed stages was 0.15+or-0.01 eV. Thermal erasure revealed at least four with energies ranging 0.85 0.95 Homogeneous illumination room gave rise fixed-developed hologram...

The effect of x-ray irradiation on the absorption and luminescence spectra KDP, DKDP, ADP has been investigated. σ-Polarized bands at 390 550 nm are induced by low temperature in three crystals. A π-polarized band also observed KDP DKDP peaked 510 nm, respectively. Thermal bleaching σ takes place ∼70 K for ∼105 DKDP. π annihilate Curie Tc both experimental data allow association bands, respectively, with radicals B A, which have previously identified EPR. same crystals during (∼10 K)...

The room-temperature kinetics of colouring in NaCl:Mn2+ has been investigated as a function concentration and aggregation state manganese. rates for quenched as-grown samples are similar at very low dose, but the curves differ markedly higher being samples. initial F-colouring increases with Mn up to approximately 90 ppm where it roughly saturates. thermal stability F centres is greater than accordance shift thermoluminescence glow peaks temperatures. A prominent band 220 nm formed under...

Photorefractive optical damage of single beams in LiNbO(3) crystals is analyzed within a framework two photoactive centres (Fe(2+)/Fe(3+) and Nb(Li) (4+)/Nb(Li) (5+)). It compares model simulations significant experimental measurements waveguides. A good agreement found the performed comparisons: photovoltaic currents, refractive index changes and, especially relevant, degraded beam-profiles. The progress wavefront has been simulated by implementing finite-difference beam-propagating method...

The erasure kinetics of holographic gratings has been studied as a function the erasing wavelength in Fe:LiNbO3. Sample self-absorption rigorously taken into account and is relevant point. After such correction, even those apparently nonexponential decays can be nicely fitted to simple exponential ones. This correction also results more reliable spectral dependence efficient transitions. photorefractive writing spectrum obtained by compensator technique. Writing show different behaviors,...

The photoplastic effect first reported by Nadeau has been extensively investigated in colored crystals of NaCl, KCl, KBr, and KI. Detailed data on its dependence strain level, F-center concentration, rate, light intensity, wavelength have obtained. excitation spectrum the follows closely shape F absorption band at room temperature as well liquid-nitrogen temperature. On other hand, magnitude Δτ fits law = C1(1 + C2v/I)−1, v being average dislocation speed, I C1 C2 constants. A theoretical...

Due to the optimistic outcomes of research on high-entropy alloys, new designs these alloys are being encouraged. We studied CoCrFeMoNi alloy and doped with Zr. In order choose best electrical equivalent circuit for prediction behavior at various potentials in artificial seawater, electrochemical impedance spectroscopy (EIS) measurements were conducted samples without Zr-doped CoCrFeMoNi. At potential levels, spectra measured between −1.0 +0.8 V vs. SCE. The study consists a preliminary...

The r33T and r31T electro-optic coefficients of congruent quasi-stoichiometric LiNbO3 have been measured with a precision better than 1 % within the range 458 nm – 1.04 µm. method has revealed wavelength dependence differences between both compositions.