The field of fluid mechanics is rapidly advancing, driven by unprecedented volumes data from experiments, measurements, and large-scale simulations at multiple spatiotemporal scales. Machine learning (ML) offers a wealth techniques to extract ...Read More

We present the key elements required for continuous variable parallel quantum information protocols based on spatial multimode correlations. describe techniques encoding, combining and detecting with high efficiency in individual transverse modes. Until now, missing feature implementation of such was generation squeezing higher order Hermite-Gauss experimentally demonstrate selective modes by fine-tuning phase matching condition nonlinear chi(2) material cavity resonance an optical...

The Beer-Lambert-Bouguer absorption law, known as Beer's law for in an optical medium, is precise only at power densities lower than a few kW. At higher this fails because it neglects the processes of stimulated emission and spontaneous emission. In previous models that considered those processes, analytical expression could not be obtained. We show here by utilizing Lambert W-function, two-level energy rate equation model solved analytically, leads into general exact accounts well reduces...

We present highly efficient sum-frequency generation between two CW IR lasers using periodically poled KTP. The system is based on the 1064 and 1342 nm laser-lines of Nd:YVO4 lasers. This an all solid-state light source in yellow-orange spectral range. optimized terms efficiency as well stability. compare performance a singly doubly resonant system, find that stability superior to system. overall conversion single higher than for configuration.

A fibre-optic laser Doppler anemometer (LDA) utilising a single-mode polarisation-preserving fibre as (transmitting) link is discussed. Since these fibres are bimodal in the sense that they can sustain two modes with orthogonal polarisations, be used to transmit beams of normal LDA which one beam frequency shifted. By rotating polarisation 90 degrees before coupling it fibre, propagate independently through and separated again at exit. The performance this type set-up investigated...

350 mW of single-frequency power from a diode-pumped solid-state Nd:YVO4 laser has been obtained coupled resonator design without any intracavity elements. Single-frequency operation was by use very short rod and design. The two resonators were formed the faces crystal an output coupling mirror. interaction cavities caused modification eigenmodes supporting action in single longitudinal mode. This design, which is extremely simple, represents cost-efficient way obtaining output.

We present a method for converting time record of turbulent velocity measured at point in flow to spatial consisting consecutive convection elements. The allows computation dynamic statistical moments such as kinetic wavenumber spectra and structure functions way that completely bypasses the need Taylor’s hypothesis. statistics agree with classical counterparts, total energy spectrum, least extents up Taylor microscale. requirements applying are access instantaneous magnitude, addition...

Phasematch curves as well sensitivity to angular and wavelength misalignment for generation of second-harmonic 785 nm 810 in Bi(3)BO(6) crystal was calculated. Measurements were done intra-cavity CW SHG a Ti:Sapphire laser. The BiBO found be excellent this application. Temperature dependance uncritical both crystals, while power stability good. Maximum blue output 53 mW at 392 100 405 nm; corresponding pump-to-blue optical conversion efficiencies 0.96% 1.82% respectively.

The increase in the circulating signal and idler fields that occurs a high- Q doubly resonant optical parametric oscillator (OPO) as it approaches resonance results small crystal temperature owing to absorption of generated fields. change affects refractive index alters path length cavity. This effect may lead self-frequency locking OPO specific fields, also peculiarities transient response system is scanned through resonance. We show experimentally observed effects are consistent with...

An analytical solution of the photoconductive material equations for dynamic holographic gratings arbitrary contrast has been obtained. A method measuring high-contrast correlation functions suggested and tested experimentally. Good agreement with expression current at high experiment is found. interesting effect transversal photocurrent predicted a number high-contrast-related topics are discussed.

We report a direct observation of space charge waves in photorefractive crystals with point group 23 (sillenites) based on their penetration into an area uniform light illumination. It is shown experimentally that the quality factor increases substantially respect to what current theory predicts [B. Sturman et al., Appl. Phys. A 55, 235 (1992)]. This results appearance strong spontaneous beams caused by wave self-excitation.

Multiple optical interference patterns generate phase gratings in Bi12SiO20 as a result of the photorefractive effect. Because nonlinear response space-charge field to pattern, these primary interact and cause formation additional at frequencies that are combinations grating frequencies. Only diffusion regime is considered present investigation. In our setup, two induced among one reference closely situated object beams. The between beams leads negligible grating, because crystal cannot...

We have developed a compact closed-form solution of the band transport model for high-contrast gratings in photogalvanic crystals. Our predicts effect photoconductivity and electric field grating enhancement due to effect. predict pronounced dependence steady-state current on contrast interference pattern an increase holographic storage time contrast. In high limit large refractive index will be shifted from position intensity modulation pattern, contrary usually adopted unshifted gratings.

We report the experimental demonstration of directly produced polarization squeezing at 1064 nm from a type I optical parametric amplifier (OPA) based on periodically poled KTP crystal (PPKTP). The orthogonal modes squeezed state are both defined by OPA cavity mode, and birefringence induced PPKTP is compensated for second, but inactive, crystal. Stokes parameter 3.6 dB anti 9.4 observed.