Recently, a new orthorhombic phase has been discovered in the ferroelectric system Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZN-xPT) for x= 9%, and 8% after application of an electric field. In present work, synchrotron x-ray measurements have extended to higher concentrations, 10% <= x <=15%. The was observed 10%, but, surprisingly, x>= 11% only tetragonal found down 20 K. thus exists narrow concentration range with near vertical boundaries on both sides. This symmetry (MC-type) is contrast monoclinic...

We study the Brillouin scattering behavior in several single-mode fibers with different waveguide characteristics terms of their longitudinal mode structures gain spectrum, linewidth narrowing, and stimulated (SBS) threshold levels. Evolution from spontaneous to SBS is investigated by monitoring line-shape acoustooptic resonance modes that exist core. compare our results current theory generated noise undepleted pump approximation. also present experimentally spectra highly depleted regime,...

$\mathrm{Pb}({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}){\mathrm{O}}_{3}$ is one of the simplest members class lead relaxors and often serves as a model system for more complicated compounds. In this paper, we analyze both polarized depolarized Raman-scattering spectra, measured in temperature range between 1000 100 K, using multiple-peak decomposition. Based on analysis, propose comprehensive picture structural transformations crystal associated dynamics. According to our model, formation...

Optical nonlinearities give rise to many ubiquitous effects in optical fibers. These are interesting themselves and can be detrimental communications, but they also have useful applications, especially for the implementation of all-optical functionalities networks. In present paper, we briefly review different kinds encountered fibers, pointing out essential material fiber parameters that determine them. We describe produced by each kind nonlinearity, emphasizing their variations values...

At the heart of relaxor behavior lies development mesoscopic or intermediate range order and low frequency relaxation dynamics associated with it. To investigate this development, we have measured Raman spectra a $\mathrm{Pb}({\mathrm{Zn}}_{1∕3}{\mathrm{Nb}}_{2∕3}){\mathrm{O}}_{3}$ (PZN) single crystal over wide temperature from $1000\phantom{\rule{0.3em}{0ex}}\mathrm{K}\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}150\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The are analyzed...

By optimizing glass composition and using a multistage dehydration process, ternary 80TeO(2)-10ZnO-10Na(2)O is obtained that shows excellent transparency in the wavelength range from 0.38 microm up to 6.10 microm. Based on this optimized composition, we report fabrication of single-mode solid-core tellurite fiber with large mode area 103 microm(2) low loss 0.24-0.7 dB/m at 1550 nm. continuous-wave self-phase modulation method, non-resonant nonlinear refractive index n(2) effective parameter...

Depolarized light-scattering spectra of propylene carbonate were obtained in the frequency range 0.2 GHz--4 THz at temperatures from 350 to 135 K. Analysis resulting susceptibility revealed reasonable agreement with predictions idealized mode coupling theory, yielding critical exponents a=0.29, b=0.50, and an exponent parameter \ensuremath{\lambda}=0.78\ifmmode\pm\else\textpm\fi{}0.05. A scaling analysis demonstrated slowing down frequencies both above below ${\mathit{T}}_{\mathit{C}}$,...

Using a physical and chemical dehydration technique high-pressure, ultradry O2 atmosphere in semiclosed steel-chamber furnace, we fabricated group of fluorotellurite glasses with composition (90-x)TeO2-xZnF2-10Na2O (mol.%, x=0-30). For x=30, no OH absorption was observed the range 0.38-6.1 μm. This is first report water-free mid-IR glass, to our knowledge, offering common advantages robust oxide glass an IR-transparent fluoride one. Besides optimized linear transmittance absorption,...

The relaxor behavior is characteristic of the class disordered ferroelectrics. These systems possess a high dielectric constant with broad relaxation peak and low frequency dispersion. Because their complexity, there exist various explanations for polarization behavior, but no unifying model. In present paper we show that simpler system, ${\mathrm{K}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}\mathrm{Ta}{\mathrm{O}}_{3}$, also generic one at that. We describe its dynamical general microscopic model...

Relatively low concentrations of randomly substituted off-center ions are known to induce ferroelectric order in highly polarizable crystals. In the case potassium tantalate (${\mathrm{KTaO}}_{3}$) doped with lithium or niobium, results first-order Raman scattering from two hard phonon modes (${\mathrm{TO}}_{2}$ and ${\mathrm{TO}}_{3}$) show that polar microregions formed at relatively high temperatures. At lower temperatures, above a certain critical dopant concentration, consistent...

In this report, we compare the temperature evolution of several physical properties relaxor systems, PZN, PMN and KTN. We show that three rather than two characteristic temperatures can be identified, T B , T* f discuss their meaning in light dielectric, Raman neutron scattering experimental results.

Diffuse scattering around the (110) reciprocal lattice point has been investigated by elastic neutron in paraelectric and relaxor phases of disordered complex perovskite crystal-Pb(Zn1/3Nb2/3)O3(PZN). The appearance a diffuse intensity peak indicates formation polar nanoregions at temperature T*, approximately 40K above Tc=413K. analysis this that these regions are shape ellipsoids, more extended <111> direction than <001> direction. quantitative provides an estimate correlation length, \xi,...

Neutron elastic diffuse scattering experiments performed on $\mathrm{Pb}({\mathrm{Zn}}_{1/3}{\mathrm{Nb}}_{2/3}){\mathrm{O}}_{3}$ (PZN) and its solid solution with ${\mathrm{PbTiO}}_{3}(\mathrm{PT}),$ known as PZN-$x\mathrm{PT},$ $x=4.5$ 9 % around many reflections show that is observed mixed indices in the transverse diagonal directions only. From width of peak a correlation length extracted. In PZN, we have reported more extended than [D. La-Orauttapong, J. Toulouse, L. Robertson, Z.-G....

Brillouin scattering spectra of the molecular glass former salol were combined with ultrasonic measurements to evaluate nonergodicity parameter mode coupling theory ${\mathit{f}}_{0}$(T). It was found exhibit a weak cusp at temperature ${\mathit{T}}_{\mathit{c}}^{\mathit{B}}$=275\ifmmode\pm\else\textpm\fi{}10 K in reasonable agreement mode-coupling crossover ${\mathit{T}}_{\mathit{c}}$=256\ifmmode\pm\else\textpm\fi{}5 recently by other methods. This result is marked contrast recent...

We characterize the distributed Raman amplification in a 70-km three spatial-mode few-mode fiber with different pump configurations and demonstrate bidirectional pumped 1050 km combined wavelength-division spatial-division multiplexed transmission same zero net gain span.

Ultrasonic study of the superconductor $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ reveals existence a shear instability centered at \ensuremath{\sim}220 K. This is manifested by large step in both longitudinal and transverse velocities. also accompanied peak attenuation. The analysis results suggests that corresponds to structural order-disorder transition.

The peculiar polar properties of ${\mathrm{KTa}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Nb}}_{\mathit{x}}$${\mathrm{O}}_{3}$ (KTN) are determined by the presence electric dipoles associated with randomly distributed Nb off-center ions. Because latter also possess an elastic quadrupole, they should permit a coupling between polarization and strain. In order to investigate this coupling, we have carried out ultrasonic study KTN for different concentrations. constants...

We present extensive stimulated Brillouin scattering (SBS) results from experiments and modeling for four different photonic crystal fibers (PCFs) with core diameters ranging 8 to 1.7 μm. These reveal several SBS characteristic features of small-core PCFs, high thresholds, acoustic peaks, which are due their antiguiding nature highly multimode character. The what we believe be new modes is examined in the light large variations observed gain, threshold, shift decreasing diameter optical wavelength.

A distributed temperature sensor based on Rayleigh scattering Brillouin optical time domain analysis (Rayleigh-BOTDA) is proposed in this paper. The uses backscattering effect of microwave modulated pulse base sidebands as probe wave and a high sensitive photon counting detector for signal intensity detection. Compared with conventional BOTDA system, the Rayleigh-BOTDA effectively suppresses polarization-induced fluctuation resulting improved intensity. experimental scheme presented...

We demonstrate the full bandwidth measurement of intermodal four-wave mixing efficiency for a 4.7-km three-spatial-mode few-mode fiber. Large fluctuations between LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> and xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> modes are experimentally observed. These exhibit strong wavelength dependence that can be persistent in time. The also shown to display some polarization dependence.

A new type of dielectric resonance has been observed in several mixed ferroelectrics, ${\mathrm{KTa}}_{1\ensuremath{-}x}{\mathrm{Nb}}_{x}{\mathrm{O}}_{3}$ (KTN), ${\mathrm{K}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}{\mathrm{TaO}}_{3}$ (KLT), and ${\mathrm{PbMg}}_{1/3}{\mathrm{Nb}}_{2/3}{\mathrm{O}}_{3}$ (PMN), also known as relaxor ferroelectrics. This its metastability (persistence over long periods time) KTN the paraelectric phase provides clear evidence, relaxors, for presence permanent polar...

${\mathrm{KTa}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Nb}}_{\mathit{x}}$${\mathrm{O}}_{3}$ (KTN) in an intermediate-concentration range (x=15.7%) has been studied using dielectric-constant and spontaneous-polarization measurements. A large peak the dielectric constant (${\mathrm{\ensuremath{\epsilon}}}_{\mathrm{max}}$\ensuremath{\simeq}70 000) is observed at temperature ${\mathit{T}}_{\mathit{c}}^{\mathrm{*}}$. From room down to ${\mathit{T}}_{\mathit{c}}^{\mathrm{*}}$+20 K,...