We report on efficient passively Q-switched operation of an Yb:YAl3(BO3)4 laser with a 2D MoS2 acting as a saturable absorber, which is the first demonstration of passive Q-switching induced by 2D saturable absorbers in the Yb-ion crystal laser. An average output power of 1.52 W at 1039.6 nm is produced at a pulse repetition rate of 585 kHz, with optical-to-optical and slope efficiencies being 29.3%

We present an easy and at the same time effective computational algorithm for tracing the interferograms of phase objects. The approach to preprocessing of interference patterns, which includes image denoising and removal of distortions, is given. We provide a detailed description of the parabola method involved in the algorithm for searching candidates for extreme points and consider the criteria

In section Acknowledgments, the Russian Science Foundation Grant No. 1871-10091 should read No. 1971-10091.

In section Acknowledgments, the Russian Science Foundation Grant No. 1871-10091 should read No. 1971-10091.

In section Acknowledgments, the Russian Science Foundation Grant No. 1871-10091 should read No. 1971-10091.

We study the possibilities of increasing the light-emission intensity of quantum wells. We describe the influence of the quantum-well width and the effective mass of charge carriers on the radiation intensity. Since the formation of negatively charged layers near the quantum well can increase the photon emission, we propose to form the charged layers with the use of ion implantation. The results of

We present an all-polarization-maintaining (PM) compact passively mode-locked fiber laser using a PM wavelength division multiplexer (WDM)-isolator-tap (WIT) hybrid device with good stability. Compared with inserting the WDM, isolator, and tap into a traditional cavity, only a PM WIT device could simultaneously inject the pump light into the cavity, control the unidirectional operation of the ring

The existence of the spherical aberration of the thermal lens in the crystal has a certain regulatory effect on the distribution of laser modes. In this paper, using the impact of this aberration on the superposition area of TEM01 and TEM10 modes, we carry out an experimental study of a 1064 nm hollow beam and its nonlinear frequency conversion providing a 532 nm hollow beam. Using a plano-concave

We analytically study the problem of pore detection and certification in bulk objects by means of radiography. For an absorbent sample, the optimum thickness for pore imaging and detection is expressed in terms of the linear attenuation coefficient of the material. This can be used to maximize the signal-to-noise ratio by tuning the photon energy of the incident monochromatic beam. The problem is more

We report the mode locking regime of dye laser pumped by 400 ns laser diode pulses. Three green laser diodes operating at 513 nm are used as the pump source. We obtain subnanosecond pulse trains using periodic 1 ns pulse modulation of the power-supply current through the pump diodes. The addition of a saturable absorber results in both a decrease in the pulse duration to 0.2 ns and a good reproducibility

We experimentally register stimulated low-frequency Raman scattering (SLFRS) in the suspension of brome mosaic virus (BMV) in phosphate buffer with very high conversion efficiency. We identify two components of the SLFRS spectrum as the breathing and quadrupole modes of BMV and determine damping characteristics and gain factors for these modes. We show that, using the core–shell model for BMV and taking

We study the propagation dynamics of zeroth-order Bessel–Gauss laser beams in plasma in the relativistic ponderomotive regime of interaction. Based on the paraxial and Wentzel-Kramers-Brillouin approximations, we derive the nonlinear evolution equation governing the laser beam width parameter, in view of the parabolic equation approach. We predict the range of intensity for self-focusing of Bessel–Gauss

We describe a novel chaotic macropulse green laser designed employing the pulse modulation of a 520 nm laser diode with optical feedback. We analyze the characteristics of these chaotic macropulses, in view of effects of the feedback intensity, injection current, modulation voltage, duty cycle, and modulation frequency on the pulses, including their full width at half maximum (FWHM) values and peak

We report the stimulated Raman scattering of light in synthetic diamond microparticles of close sizes (250–300 μm) with the generation of three Stokes satellites under the excitation by ultrashort (60 ps) YAG:Nd3+ laser pulses at a wavelength of 532 nm. The studies performed open up the possibility of creating a laser frequency array with a frequency shift of 1332 cm–1 based on stimulated Raman scattering

Applying the combination of the master and stochastic differential equations, we investigate in detail a continuous-variable entanglement of the twin beam generated by the coherent beat laser containing a parametric amplifier and coupled to thermal light of an external environment. The dipole-forbidden transition of the three-level atoms are coupled by the initial coherent superposition and classical

We study the earliest steps in the radiolysis of a water pentamer in an intense, 800 nm, linearlypolarized fs laser field [I = (0.1 − 50) ∙ 1014 W/cm2] through a real-space, real-time implementation of time-dependent density functional theory nonadiabatically coupled to molecular dynamics. The ionization is enhanced with increasing laser intensity, resulting in the continuous emergence of higher charge

We use Letokhov’s concept of stochastic feedback to interpret experiments on X-ray spontaneous emission from a polydisperse plasma of a nanosecond vacuum discharge (NVD) with a virtual cathode. We develop a diffusion model of stochastic propagation of spontaneous X-ray radiation in the volume of randomly located reflecting clusters. The model provides qualitative explanation of both the experimentally

We propose a temperature sensor based on the graphene-oxide-coated micro-nano-fiber Mach–Zehnder (MZ) interference structure. In the design of the sensor, we use a single-mode fiber and multimode welded micro-nano fiber as a substrate to deposit graphene oxide (GO) by natural deposition. We cover the surface of the micro-nano fiber by a temperature-sensitive material in order to increase the temperature

In this letter, we demonstrate the performance of the Tm:YLF and Tm:YAP slab lasers in free running. Both slab crystals are a-cut with a doping concentration of 3 at.%. Under an incident pump power of 376 W, maximum output powers of 130 and 126 W are obtained from the Tm:YLF and Tm:YAP lasers with the emissions peaks at 1909.4 and 1990.4 nm, respectively. The corresponding optical conversion efficiency

We study a continuous-wave sum-frequency blue laser operating at 484 nm. The laser elaborated is based on the intracavity pumping technology. A 912 nm laser produced by an end-pumped Nd:GdVO4 crystal, using an 808 nm fiber-coupled laser diode, is employed to pump an Yb:YAG crystal in the cavity to achieve the simultaneous oscillations in 912 and 1030 nm lasers. An intracavity sum-frequency achieved

Considering two mixed mechanical resonators, we investigate two different kinds of quantum correlations, i.e., entanglement and quantum discord. We use two Fabry–Pérot cavities coupled by squeezed light. To quantify entanglement and quantum discord, we employ respectively the Gaussian intrinsic entanglement and the Gaussian Hellinger discord. We found that these two forms of quantum correlations decay

Now it is indisputable fact that the Earth’s aerosphere contains Kolmogorov and non-Kolmogorov turbulence, which has been confirmed by increasing experimental evidences and theoretical investigations. Based on this, the scientific community conducts investigations on the combined influence of Kolmogorov turbulence and non-Kolmogorov one on optical wave propagating in the aerosphere. In this paper,

We present the influence of phase fluctuations on the entanglement and intensity of the radiation produced by a correlated-emission laser. The three-level atoms are initially prepared in a partial coherent superposition of the ground and exited states, and the driven radiation field incoming via the input mirror induces the atomic coherence that leads to the entanglement in the quantum system. The

In this work, we design a D-shaped photonic-crystal fiber (PCF) sensor with a large-hole self-reference channel based on the surface plasmon resonance. Using the numerical calculation method, we study variations of the transmission spectrum with concentration for the aqueous glucose solution. By optimizing the silver-film thickness of the reference and detected channels, we find that the sensitivity

We demonstrate a stable compact passively Q-switched laser generating 40 μJ, subnanosecond (< 1 ns) duration, 1064 nm pulses at a repetition rate of 10 kHz. With a composite Nd:YAG/Cr4+:YAG crystal in a simple and compact resonator end-pumped by intense 808 nm pulse, we effectively improve the stability of output laser pulses corresponding to the interpulse amplitude instability less 1% (rms) and the

The copper vapor laser (CVL) is the most powerful and efficient resonance metastable metal-vapor laser having widespread applications. Jitter requirements are very stringent when the CVL is operated in the oscillator–amplifier configuration. Jitter in the laser affects proper synchronization and thereby affects the output power and its stability. Although thyratron-based power supplies have low jitter

For Hermitian and non-Hermitian Hamiltonian matrices H, we present the Schr¨odinger equation for qudit (spin-j system, N-level atom) with the state vector |ψ〉 in a new form of the linear eigenvalue equation for the matrix ℋ = (H ⊗ 1N) and the probability eigenvector |p〉 identified with quantum states in the probability representation of quantum mechanics. We discuss the possibility to experimentally

We analyze the features of nonlinear refraction in colloidal solutions containing Ag2S quantum dots capped with thioglycolic acid (Ag2S/TGA) or L-cysteine (Ag2S/L-Cys), with the quantum-dot (QD) sizes ranging from 1.7 to 5.5 nm and their concentration in the solution being 0.1%. The Z-scans of the samples were obtained using 10 ns pulses of 532 nm radiation. For samples with various average sizes and

Based on the results of quantum field theory and quantum electrodynamics on virtual photons as quanta of electromagnetic interaction, we discuss the interpretation of quantum indeterminacy, uncertainty relations, and physics, which determine the probabilistic statistical character of quantum phenomena. We discuss the fundamental reasons for the appearance of the Planck constant in the uncertainty relations

We demonstrate a 2.5 m ring laser with the Ho:YAG and Ho:YLF crystals end-pumped by the Tmdoped fiber laser. In the Ho:YAG laser, the continuous-wave (CW) output power was 4.72 W at a wavelength of 2090.8 nm when the incident pump power was 21.5 W, which corresponded to a slope efficiency of 26.3%. For the Q-switched operation with the 100 Hz pulse repetition frequency (PRF), an output energy of 5

In this study, we measure the output current of a silicon-based positive-intrinsic-negative (p-i-n) quadrant photodetector (QPD) exposed to a millisecond-pulse laser radiation. We study the output current curve for a cell at different laser energy fluences and pulse widths. The results obtained show that the behavior of the output current involves a holding current stage as the photo-generated current

We report on high-power laser-diode (LD) end-pumped Tm:YLF innoslab lasers with different doping concentrations of 2, 2.5, and 3 at.% with a single-end 792 nm LD stack. After series of experiments, we conclude that 3 at.% Tm:YLF lasers can produce a maximum output power of 84.7 W; this value is higher than that of the lasers with two other doping concentrations at the same incident pump power equal

We consider the interaction between two three-level atoms in the Ξ configuration and a quantum system described through SU(1) group algebra operators. To study the quantum phenomena and underlying dynamical behavior, we calculate the wave function of the system. In particular, we investigate collapse and revival phenomena, the correlation function, and the Husimi quasidistribution Q-function.

Luminescence spectra of polytetrafluoroethylene (Teflon), a Teflon film, and a polyethylene film are registered in wide wavelength range under excitation by radiations with different wavelengths. For the first time, we detect two-photon-excited luminescence in polymers at low intensity of exciting light. In Teflon, we also register luminescence in the blue range under excitation by ruby laser pulses

Thin film of oriented crystalline intrinsic polysilicon films were grown on alkali-free borosilicate glass substrate using hot-wire chemical-vapor-deposition (HWCVD) technique. A layer as a source of phosphorus dopant on top of intrinsic polysilicon films were introduced in two different approaches: (i) spinon one-micrometer-thick phosphorus dopant and (ii) phosphorus ion implantation. We investigate

In this paper, we provide the laser-induced breakdown spectroscopic (LIBS) analysis of copper under the action of the ultrafast picosecond Nd:YAG laser and the specifications calculated from the electron temperature of plasma generated by the fundamental (1064 nm), second (532 nm), third (355 nm), and fourth (266 nm) laser harmonics. In this work, a laser pulse energy of 60 mJ±5% with a duration of

In this paper, we show that the energy spectrum of a qudit system (spin-j, N-level atom) with Hamiltonian N×N matrix H is determined by the equation for eigenvalues of the N2×N2 matrix ℋ and its eigenvectors | p⟩ with components, which are probability distributions identified with quantum states in the probability representation of quantum mechanics. We derive this equation based on the conventional

In spatial division multiplexing (SDM)-based communication systems, each spatial mode can act as an independent information-bearing carrier capable of scaling the total transmission capacity by several orders of magnitude. It has been reported that in SDM networks the signal amplitude depends upon the optical-path-length (OPL) difference between the various optical modes. In this work, we realize SDM

Oceanic turbulence is one of the important factors that affect the transmission of quantum optical signals in the seawater medium. However, up to now, none research on the influence of oceanic turbulence on the parameters of quantum communication channel is in progress. In order to fill such vacancies, we simulate in this paper the relationship of oceanic turbulence parameters to the optical wave structure

Wave packet fractional revivals appear as manifestation of a multiple interference of various components of a wave packet during its long-time evolution in a bounded system. We study the phenomenon of fractional revivals by means of the time-dependent interference of information entropy density associated with a bound-state wave packet, which exhibits the formation of self-similar structures – quantum

Earlier, in experiments on DD synthesis in a complex plasma of a nanosecond vacuum discharge (NVD) with a virtual cathode, in parallel, a significant experimental database was accumulated on the output of hard X rays from the inter-electrode ensembles, and a certain correlation was established between the specificity of the X-ray yield and the features of the inter-electrode ensembles of nanoparticles

We develop the quantizer–dequantizer formalism for the probability and mean-value representations of qubits and qutrits. In these representations, the elements of symbols of operators are measurable physical quantities. We derive the star-product kernels, which lead to explicit expressions of the associative product of the symbols of the density operators and quantum observables for qubits. The extension

We propose and experimentally demonstrate a simple and stable photonic approach of frequencydoubled triangular-shaped waveform generation. It mainly consists of an integrated polarizationmultiplexing Mach–Zehnder modulator (PM-MZM) and a balance photoelectric detector (BPD). Two PM-MZM sub-modulators work at the maximum transmission point. By properly setting the amplitude of the local oscillator (LO)

We present a chaotic lidar for underwater ranging and three-dimension (3D) imaging applications. The lidar transmitter based on a laser diode with free space optical feedback is designed to generate 520 nm wavelength wideband chaotic signal. This transmitter is used with a correlation-based lidar receiver to perform a ranging demonstration in clean water with a measured attenuation coefficient of 0

X-ray lasers based on transitions in highly-charged Ni-like ions generating in the “water window” wavelength range can be pumped by compact laboratory discharge sources. In this paper, we report the results of numerical simulations of the plasma dynamics and kinetics in an X-ray laser based on transitions in Ni-like xenon ions. The laser active medium is created by an extended low-inductive high-current

We investigate the operating modes of diode lasers in the external cavity scheme of spectral beam combining, using the virtual laser-diode array method. We determine the spectral range of the diode array and the watt–ampere characteristics of a single-diode laser for various wavelengths. We experimentally show that by varying the output coupler transmission with the wavelength, one can optimize the

We consider the implementation of the logical operation of disjunction of signals using accumulated stimulated echo holography. We study the processing of information embedded in the laser pulses of a pulse pair, with one of the pulses in the pair being an object and the other one having a wide frequency spectrum. We show that, taking the pulse spectra as narrow frequency regions within the inhomogeneously

We investigate the first-Stokes operation of YVO4 crystal driven by an acousto-optic Q-switched Nd:YAP laser with X(ZZ)X Raman configuration. The fundamental wavelength laser operation by Nd:YAP crystal was at 1080 nm corresponding to the first-Stokes wavelength at 1195 nm based on the Raman shift of 890 cm−1 in a-cut YVO4 crystal. Under an incident pump power of 8 W and a pulse repetition frequency

We investigate increase in the surface temperature of biased Si avalanche photodiodes (APDs) fabricated in an external capacitor circuit irradiated by a millisecond-pulse laser. The results obtained show that different external capacitance parameters have different effects on the temperature rise, the smaller the capacitance of external capacitor, the lower surface temperature increase in the APD.

In this work, we demonstrate a passively-Q-switched 1.33 μm Nd:Lu2YSc1.5Ga3.5O12 (Nd:LuYSGG) laser based on the Bi2Se3 topological insulator (TI) as a saturable absorber (SA). We obtain pulse widths as low as 146 ns at a pulse repetition rate of 349.5 kHz and a pulse energy of 1.03 μJ, which provides a peak power of 7.05 W. These results represent some of best yet published in terms of repetition rate

We design a high-sensitivity optical-fiber sensor for measurements of displacement and refractive index based on dual-coating-stripped loop-shaped single-mode fibers. For this, we produced two unrelated interference dips as a consequence of different radii of two loop-shaped fibers. Since loop-shaped optical fibers are assigned different tasks at the same time, the two dips present their own characteristics;

In this paper, we propose a three-dimensional (3D) integral image display method that uses the similarity of corresponding points in a series of axially recorded images. First, we calculate the corresponding points of a 3D object, in view of the proportional relationship of the distances of points in the elemental images collected, using axially distributed sensing (ADS). Next, we extract the depth

We study the emission spectrum and quantum-state fidelity for an atomic system interacting with radiation fields of quantum systems described by power-law potentials. We consider a set of manifold fields that are characterizable by their level-energy differences. They include triangular, infinite, and harmonic potentials as special cases. We present the time evolution of the spectrum and fidelity for

We derive the analytical expression of the probability density of orbital angular momentum modes for elegant and standard Laguerre–Gaussian beams in turbulence. The results show that we can increase the initial topological charge of the beams to reduce the detrimental mode crosstalk induced by the turbulence. We also discuss the influence of the beam parameters on the probability of signal and the

We study the employment of an adopted optics system for the reduction of thermal blooming effects by the phase correction of a 1.064 μm laser. The energy concentration of the beam spot in the farfield substantially increases if the adaptive optics system is performed in a closed loop. The phase compensation of the adapted optics system is effective for a Bradley–Hermann distortion number of less than

We present quantum formula for extropy based on the Husimi Q-function and the atomic Husimi Q-function. The quantum extropy is used to detect the entanglement or nonlocal correlations of the system consisted of a single qubit and the radiation field. We provide explicit forms of the binomial and even binomial distributions. We compare the temporal behavior of quantum extropy within the atomic and field

Based on the finite-difference-time-domain method and the plane-wave method, we study the imaging performance of two-dimensional hexagonal-structure photonic-crystal flat panel lens. First, the plane wave expansion method is used to verify that the structure has a negative refraction effect. The equivalent refractive index is – 1 when the normalized frequency is 0.251. The finite-difference-timedomain

The passively Q-switched (PQS) operation of a Tm:YAP laser was experimentally demonstrated with an MoSe2 saturable absorber (SA). In the PQS mode, an average output power of 1.084/1.744 W with a pulse width of 686.0/1222 ns at 196.5/177.7 kHz was acquired from Tm:YAP laser under an output couple (OC) with transmittances T of 2%/5%, corresponding to an optical–optical conversion efficiency and an output

We present a passively Q-switched Ho:Sc2SiO5 microchip laser with a molybdenum disulfide saturable absorber for the first time. The molybdenum disulfide materials are fabricated on the end surface of a microchip Ho:SSO crystal. The physical length of the laser cavity is only 3 mm. Three output couplers with different transmissions are utilized to test the passively Q-switched laser performance. The

We report a stable high-power all-solid-state Q-switched laser operating at 294.6 nm with a pulse width of 24 ns and a repetition rate of 20 kHz produced by intracavity sum-frequency generation and external frequency doubling in LiB3O5 and β-BaB2O4 crystals, respectively. Upon synchronizing the fundamental lasers, the maximum output power at 589 nm is 1.2 W, which is frequency doubled to produce up