We propose a potentially practical scheme for constructing a quantum network based on a system where three waveguides are coupled to two two-level atoms. In the case of chiral couplings between the waveguides and atoms, we realize a directed single-photon router and the efficiency of single-photon routing reaches 100%. In addition, in this network, the photon input from one port of the channel can

We propose the design of a high-power fiber oscillator with chirped and tilted fiber Bragg gratings (CTFBGs) to suppress the stimulated Raman scattering within the fiber cavity and in the delivery fibers. A high-power single-mode fiber oscillator system was constructed for demonstration. With a CTFBG inserted into the fiber cavity, obvious Raman suppression was observed and the output signal laser

We report the laser-ablative fabrication of antibacterial nanostructures, combining mechanical and chemotoxic effects, by femto- and nanosecond laser ablation and their testing on Staphylococcus aureus and Pseudomonas aeruginosa strains. A Ti surface, covered with nanospikes and periodical surface ripples, provides a strong anti-biofilm effect, and the addition of cytotoxic nanoparticles (NPs) (Ag

Optoacoustic (OA) angiography allows high-contrast three-dimensional (3D) visualization of hemoglobin-containing structures ranging from micrometers to millimeters. However, due to the large amount of 3D data acquired by modern high-throughput OA systems the resulting OA vasculature images might be difficult to analyze visually. This problem is especially relevant for monitoring of angiogenesis of

In this paper we study quantum correlation (QC) swapping between two different kinds of quantum-correlated states. To be concrete, one is the famous Werner state while another is a kind of separable state. We employ measurement-induced disturbance (Luo 2008 Phys. Rev. A 77 02230) as the quantifier to characterize and quantify QC. We work out QCs in all the concerned states and concretely analyze their

In this paper an off-axis holography is put forward based on the Sagnac interferometer. The holograms of alumina-dust aerosol particles, an United States Air Force 1951 resolution plate and paramecium were recorded in the experiment. The diffraction integral of a plane hole derived from quantum theory is illustrated by the variation of the thickness of interference fringes. We use an angular spectrum

In this work, we report a tunable mode-locked fiber laser that can produce ultrashort laser pulses with polarization vortex. Two vortex wave plates (VWPs) are employed in this laser to convert the intracavity beam states between the Gaussian mode and cylindrical vector mode. By adjusting the angle between a diffraction grating and the light beam in the cavity, the center wavelength of the mode-locked

We present the results of investigation of total internal reflection of a femtosecond light filament in a LiF crystal in the regime of anomalous group velocity dispersion. We measure the Goos–Hnchen shift of the filament in the vicinity of the critical angle for a single femtosecond pulse using the laser coloration method. The obtained experimental values are compared to several existing theoretical

In this paper, we consider the relationship between C Shannon’s unicity distance, which is determined by the number of symbols of the encrypted message required to uniquely find the encryption key of the cryptosystem in information-theoretical sense, ε-secrecy criterion in quantum cryptography and Holevo information. A lower bound for the unicity distance for ε-secret keys in quantum cryptography is

Experimentalists have long sought a method that allows them to control the branching ratios of an unstable particle decay and direct some decay to follow one specific desired channel without another. The powerful laser could make this a reality. In this letter and within the framework of the standard electroweak model, we investigate theoretically the laser effect on the branching ratios of different

Facial nerve palsy involves paralysis of unknown origin caused by trauma, infectious disease or metabolic disorders. The aim of this study was to employ low-level laser therapy (LLLT) in the recovery of two patients with facial nerve palsies due to trauma and Bell’s palsy (BP), respectively. LLLT was used with a gallium aluminum arsenide laser (780 nm) in the first case and in the second case LLLT

We describe a method that allows accumulation in a Paul trap of a large number of ions obtained from multiple laser ablation pulses, and therefore solving the problem of a single pulse that usualy gives rise to final trapping of too few ions. The proposed method of the cumulative trap loading was based on interaction with a buffer gas that provided a friction force. The method was applied to triply

Within the frame of electrodynamic and nonlinearly Thomson scattering, we study the motion and spatial radiation features of a static electron irradiated by circularly polarized tightly focused laser with different laser intensities. Combining the existing and our novel 3D Oxyz coordinate analysis, we find the azimuthal divergence and peak radiation azimuth decrease at varied speeds with laser intensity

An analysis of weak quantum fluctuations of a spatial soliton in a laser with fast saturable absorption in the possible presence of weak holding radiation is carried out. In the c-number representation with adiabatic elimination of atomic variables, the master Heisenberg–Langevin equation is linearized in the vicinity of a stable classical (in the absence of fluctuations) laser soliton. The linearized

Increasing the conversion efficiency of second harmonic generation (SHG) is an area of interest in research. We report a high-efficiency 532 nm laser generation, with a conversion efficiency of 94.04 0.115% from the pump depletion of 98.1% 0.1%, by accurately quantifying the round-trip loss and the transmissivity of the input mirror using our proposed scheme. The optimal conversion efficiency of the

This article investigates the performance of a free space optical (FSO) communication link by incorporating the device parameters that influence the optical output power of the quantum cascade laser (QCL). The transmitter side of the FSO link consists of gain-switched QCL operating at 9 m. Short optical pulses possessing minimum full width half maximum (FWHM) and peak power as a result of ON-OFF keying

The article demonstrates the fundamental possibility of creating microstructures for various functional purposes using the capabilities of the two-photon femtosecond polymerization method. The developed technological approach for creating a micro-optical holder for standard single-mode and multimode fibers is demonstrated. This type of holder can be used to manufacture a unit for optical matching of

Thin films of zinc oxide and those doped with terbium (at concentrations of 0.1–5.0 mol%) were synthesized on glass substrates using the sol–gel method. The UV–Vis transmission spectra showed that transparency increases from 60% to 86% with an increase of Tb content. All terbium-doped samples exhibit a rise in Eg from 3.37 eV for zinc oxide to 3.827 eV for doped films. The photoluminescence (PL) of

By using the Lyapunov control approach—an optimization algorithm, we propose a dissipative scheme for efficiently preparing the three-dimensional entangled state of two Rydberg atoms, which subject to Rydberg–Rydberg interactions at the antiblockade regime. The steady target state is the unique dark state of the two-atom system, and is achieved with high fidelity under the Rydberg pumping and the atomic

Transmission versus intensity in 100 μm CaF2 and UV fused silica samples at a wavelength of 473 nm for different durations of the initial pulse was studied. Fitting the experimental data with a model based on the solution of the nonlinear Schrdinger equation and taking into account multiphoton absorption and absorption by the plasma, as well as the Kerr nonlinearity, diffraction and dispersion of the

A quantum digital signature (QDS) is guaranteed by the laws of quantum physics and can provide unconditional security to authenticate classical messages. Previous QDS protocols that shared secret keys could be realized using discrete-variable quantum key distribution (DV-QKD), for which the DV-QKD relied on extreme requirements like single-photon detection and extremely weak pulses of light. QDS protocols

Vortex beams have wide applications in optical tweezers, optical communications and so on. Long period fiber gratings, mode selective couplers, few mode fiber Bragg gratings or specially designed fibers are often used to generate vortex beams from fiber lasers. New methods of mode selection in fiber lasers are always attractive. When transverse modes propagate along a multimode fiber, the polarization

The long-term hydrodynamics of laser generated plasma regions are dictated by the spatial distribution of the deposited laser energy. Using an integrated chemical-optical solver to track energy deposition from single and dual nanosecond laser pulses, we show that self-defocusing results in a biased growth of the plasma region towards the focusing lens. This displacement of energy deposition scales

Single-pixel imaging (SPI) uses point detectors instead of expensive array sensors to capture images under low light conditions. It therefore provides a solution in detecting objects with weak signals. In this research, we propose a non-line-of-sight (NLOS) 2D transparent object inspection system based on SPI technique. The 2D shape of the transparent object is reconstructed using Total Variation Augmented

Optical frequency combs (OFCs) generated in microresonators with whispering gallery modes are attractive for different applications and basic science. The effects associated with Raman nonlinearity are constantly being discovered and investigated experimentally and theoretically expanding the capabilities of microresonator OFCs. Here we obtain experimentally Raman-assisted nested OFCs in two different

We present the closed-loop controlled compensation of the thermally induced lens in a high-power thin-disk oscillator to obtain fundamental-mode operation over a wide range of pump powers. The radius of the oscillating beam was measured in real time at the position of the thin-disk crystal. This signal was used by the control system to adapt the curvature of a spherically deformable mirror to maintain

An ensemble of thorium-229 ions embedded by pulsed laser implantation into a matrix of a broadband dielectric-silicon oxide is studied. The results of the experimental investigation of thorium ions’ lifetime as charged components of the Th+/SiO2/Si system formed immediately after laser implantation are presented. The modelled theoretical description takes into account the instantaneous charging of

We investigate polarization-locked vector solitons (PLVSs) arising in an all-polarization-maintaining (PM) soliton fiber laser mode-locked by a carbon nanotube. The laser can operate stably in both Q-switched and mode-locked states with different pump power. Under the PLVS condition, we observe a string of peak-dip-pair sidebands after polarization-resolving measurement, indicating the strong and regular

Temperature sensors based on photonic crystal fibers (PCFs) have attracted considerable attentions due to their desirable advantages. However, the real-time temperature sensing in the temporal region is rarely studied. Here, an all-fiber real-time high-sensitivity temperature sensor is fabricated based on the high-order soliton compression process. A 1560 nm femtosecond fiber laser is used as the injected

The application of metasurface in invisibility technology is mainly based on its phase control function, which provides a new choice for the design of ultra-thin carpet cloaking devices with arbitrary shape. At present, most of the carpet cloaking devices mainly focus on metal structure metasurfaces. The Ohmic loss of metallic materials seriously affects the efficiency of cloaking devices. To reduce

The formation of entanglement between the electronic and vibrational subsystems of two interacting molecules localized between tunneling contact leads was theoretically analyzed using the Keldysh diagram technique. The time evolution of concurrence after ‘switching on’ the coupling between the molecules was investigated. It was revealed that non-zero concurrence can be present in the system in the

In this work we report on a tandem pumped gain-switched Yb-doped fiber laser. We used an amplified dissipative soliton resonance mode-locked fiber laser with the wavelength of 1030 nm as a source of high repetition rate pulsed pump, incorporated with a CW diode laser at the wavelength of 976 nm in hybrid pump scheme. Sub-nanosecond narrow line-width gain-switched pulses with peak power of 10 kW at

A single-resonant beta barium borate crystal optical parametric oscillator with high pulse energy output at the H-β Fraunhofer line of 486.1 nm was demonstrated. Pumped by a single-frequency 355 nm ultraviolet pulsed laser at 10 Hz repetition rate with maximum pulse energy of 411 mJ, maximum output energy of 162 mJ blue laser pulse at 486.1 nm was successfully obtained from a plano-concave cavity with

We examine two types of information loss function encountered in optical neural recording—the uncertainty of neural states encoding an external stimulus and the incompleteness of information that laser-excited fluorescence can read out from these neural states. We show that, even though these uncertainties are of distinctly different nature, they can be treated on an equal footing against the Fisher

We study the generation of terahertz (THz) radiation from a dual-color filament in air for a Ti:sapphire pump and with different wavelengths of the seed pulse using the unidirectional pulse propagation equation (UPPE). The local transient photocurrent model indicates that the most efficient THz generation corresponds to the seed with either halved or doubled pump frequency compared with the other seed

In this paper, an asymmetric multiple-image cryptosystem is proposed using LUP decomposition (LUPD) in the spherical diffraction (SpD) domain. To the best of our knowledge, the SpD transform is applied to the optical encryption for the first time. In the proposed cryptosystem, multiple grayscale images are encoded into a sparse and binary amplitude distribution with the cascaded LUPD and SpD transform

Since the multi-level activation function quantum neural network (QNN) for pattern recognition was firstly proposed by Purushothaman and Karayiannis, more and more researches have been conducted on improving it. However, they all ignore that the QNN only uses multi-level activation function to simulate the concept of quantum superposition rather than really using quantum computing. In this paper, we

Multimode optical fibers (MMF) recently attracted a renewed attention, because of their potential for spatial division multiplexing, medical imaging and high-power fiber lasers, thanks to the discovery of new nonlinear optical effects, such as Kerr beam self-cleaning, spatiotemporal mode-locking, and geometric parametric instability, to name a few. The main feature of these effects is that many transverse

Generation of colloidal gold nanoparticles was for the first time studied at ultra-high, multi-MHz repetition rates of 10 ps, 1030 nm laser pulses, ablating 70 nm gold film in water at the constant average power of 270 W and focusing conditions. Ultrafast (550 m s−1) laser scanning of gold films was facilitated by a polygon reflector, provided single-shot per spot through ablation of the films. According

Quantum tomography makes it possible to obtain a comprehensive information about certain logical elements of a quantum computer. In this regard, it is a promising tool for debugging quantum computers. The practical application of tomography, however, is still limited by systematic measurement errors. Their main source are errors in the quantum state preparation and measurement procedures. In this work

The motion of a magnetic levitation structure can lead to low accuracy for magnetically suspended control moment gyros (MSCMG), artificial heart pumps or high precision stable platforms. Measuring this motion is important in orbital navigation and precision measurement technologies, but current methods are unable to measure it with high accuracy under a strong magnetic field around the magnetic levitation

A femtosecond optical technique has been developed for studying a highly absorbing microplasma created in a volume of transparent media under intense laser radiation. The approach, which combines interferometric and shadow microscopy and allows reconstructing induced changes in the optical properties of a medium, is described. The results of investigation of the refractive index dynamics in water bulk

We propose a scheme for subwavelength three-dimensional (3D) Rydberg atom localization in a (V + Ξ)-type atomic system by spatial optical absorption microscopy. Position-dependent atom–field interaction allows atom position information to be obtained via measurement of the probe absorption. Some distinctive spatial localization patterns are discovered by adjusting the detuning and Rabi frequency of

A semiclassical analytic theory which describes the excitation of atomic Rydberg states by intense laser radiation is formulated in the multiphoton limit of ionization. The theory is based on the separation of the electron motion in fast oscillations in the laser field and slow scattering in the Coulomb field of the nucleus. It allows one to calculate classical cut-off positions in the distribution

Multiphoton catalysis is a non-Gaussian operation which has aroused interest recently in quantum information processing. There are two schemes of multiphoton catalysis in the current literature: one uses a beam splitter, while the other uses an optical parametric amplifier. We derive the catalysis operator in the Fock basis for each scheme and find a close relationship between them. We propose to enhance

The effect of self-induced transparency is investigated for a three-level system with a V-scheme of the allowed transitions in the case where one of the transitions is resonant while another one is quasiresonant. The generalized system of the wave and material equations for the resonant transition, taking into account the presence of a quasiresonant transition, is derived. This system is integrable

Terahertz radiation is investigated using nonlinear interaction of a laser beat wave with a density-modulated medium of graphite nanoparticles. A beam-decentering parameter, b, is used to modify the polarizing field’s profile to produce different-shaped laser pulse envelopes, e.g. Gaussian, top head, ring-shaped and cosh-Gaussian. The normal vectors corresponding to the basal planes of graphite nanoparticles

We propose a scheme to realize super sub-wavelength interference in virtue of high-order spatial correlation with a programmable light source, which can be applied to enhance precision in measurement and control. In this proposal, the light source is produced by modulating the wavefront of a laser beam randomly in time with a phase-only spatial light modulator (SLM). Combing the intensity patterns

Zero-index metamaterials are widely used in electromagnetic devices due to their favorable optical properties such as infinite large-phase velocity and quasi-infinite wavelength. However, insufficient bandwidth and high loss seriously limit the wide application of zero refractive index metamaterials (ZIMs), especially in the terahertz band. Here, we propose a kind of supercell microstructure metamaterial

We report the development of a thermally stable laser-driven phosphor-converted white light source using a multilayer structured diffuser system for general illumination. The developed extended diffuser system comprises an acrylic sheet, two glass plates, and a phosphor layer with the arrangement in a glass-acrylic-phosphor-glass combination. The high-power laser beam was gradually distributed inside

Trapped ions have proven to be a powerful instrument in quantum logic, precision metrology and tests of fundamental theories. Many applications require isotopically pure ion crystals to be trapped; however, selective loading methods require either isotopically pure atom sources or dedicated ultraviolet laser systems. Here we investigate the loading dynamics of the isotopically pure magnesium ion crystals

In this paper, we put forward a protocol for the complete and nondestructive Bell-state measurement of trapped ions. We show that the four different Bell states of two information carriers can be distinguished using two auxiliary ions with the initial Bell states unchanged after the procedures. The parameter selections are discussed based on the experimentally available parameters, and the robustness

The prospects for using multicomponent films produced by aerosol spray pyrolysis for doping bulk ZnSe crystals with optically and electrically active impurities are shown for the first time. Lasing was obtained on ZnSe:Cr active elements doped during hot isostatic pressing treatment from CrS and CdS:Cr films. The lasing efficiency with respect to the absorbed radiation energy at a wavelength of 1.94

High-power Faraday isolators (FIs) for mid-IR radiation are of great practical importance, since they expand the capabilities of constructing optical schemes of solid state mid-IR lasers, which have progressed significantly in recent years. Isolators for high-power radiation with a wavelength of 1.5–2 m are especially important for the solid-state lasers in order to cover the entire mid-IR range. We

Upconversion nanoparticles (UCPNs) capable of emitting near-infrared (NIR) light under NIR excitation attract much attention for bioapplications. However, the low upconversion efficiency and emission intensity significantly limits the progress in utilizing UCPNs. The present work is dedicated to the enhancement of upconversion efficiency and NIR luminescence intensity. The theoretical model that describes

Precision measurement plays a very important role in many field including optics, astronomy, biochemistry, atmospheric science, environmental engineering, dusty plasma, etc. Here, we propose an efficient scheme to investigate the relationship between linewidth and radius of the metal nanoparticle (MNP) in a hybrid optical microcavity system that included a quantum emitters interacting with a MNP. By

In this manuscript, we propose a graphene metasurface composed of an L-shaped pattern to achieve a tunable circular dichroism under oblique incidence in the mid-infrared region. For our graphene extrinsically 3D-chiral structure, there are two graphene localized surface plasmons resonant modes at the wavelength of 11.05 and 16.69 μm. A broad bandwidth circular dichroism between the two modes is generated

In a local quantum network, multi-qubits in various entangled states might be distributed in different remote nodes due to some peculiar demands. In this paper we consider a seven-qubit entangled state in a given qubit distribution among three participants and study its capacity in quantum teleportation (QT). To be specific, we put forward three controlled QT schemes utilizing the state. In each scheme

We demonstrate passively mode-locked erbium/thulium doped fiber lasers (TDFLs) operating at 1560/1950 nm by using a common gold nanorods (GNRs)/D-shaped fiber as saturable absorber (SA). The SA is prepared by the composite of GNRs with an average aspect ratio of 5.3 and D-shaped fiber, which has broadband absorption from 1000 nm to 3000 nm. By inserting the same SA into an erbium or thulium doped fiber

Chronic rhinitis (CR) is among the most frequent inflammatory diseases of ear-nose-throat (ENT) covering up to 30% of the population. Different forms of CR require different treatment tactics, which indicates the need for an efficient tool for differential diagnostics of CR. Optical coherence tomography (OCT) is a promising tool for fast non-invasive evaluation of nasal mucosa, which, however, requires