Three-level Laser Research Articles

Quantum correlations in a coherently pumped cascade three-level laser in the presence of dephasing

Quantum correlations in a coherently pumped cascade three-level laser in the presence of dephasing

Coherently driven nondegenerate three-level laser coupled to squeezed vacuum reservoir

Coherently driven nondegenerate three-level laser coupled to squeezed vacuum reservoir

Dynamics of two degenerate three-level lasers oupled to vacuum reservoir

Dynamics of two degenerate three-level lasers oupled to vacuum reservoir

Quantumness of correlations in a nondegenerate three-level laser

Quantumness of correlations in a nondegenerate three-level laser

Surface Texturing and Wettability Modification by Nanosecond Pulse Laser Ablation of Stainless Steels

Laser surface texturing has attracted growing interest, particularly in functional surface modification. Lasers with nanosecond pulse widths and infrared wavelengths are commonly used for metallic surface texturing because of their low cost and potential for fabricating a large range of textures. In this research, a laser with a nanosecond pulse width and infrared wavelength was used for the surface texturing of 316 stainless steels. Standard grooved and near-isotropic surface textures, as well as novel porous texture and feather-like dendrite texture, were fabricated through single-time laser texturing. Water contact angle tests were performed on the post-process surfaces, and they showed wettability changes from superhydrophilic to superhydrophobic according to different types of textures. Discussion on the relationship between water contact angle and surface roughness, groove width/depth ratio, surface carbon and oxygen contents indicated that it is the surface morphology that impacts changes in wettability. The comprehensive formation mechanism of different textures and the wettability control mechanism through different textures have been systematically discussed. For the first time, the three-level (point-line-area) laser surface ablation mechanism has been established. The proposed findings can be used for future laser texturing process designs on metals using lasers with a nanosecond pulse width and an infrared wavelength for various applications including wettability modification.

Dynamics of three-level laser pumped by electron bombardment

Dynamics of three-level laser pumped by electron bombardment

Gaussian Rényi-2 correlations in a nondegenerate three-level laser

Gaussian Rényi-2 correlations in a nondegenerate three-level laser

Design of three-level Nd-doped laser fiber based on anti-resonant structure

900-nm Nd-doped fiber laser can find widespread applications including biomedical diagnosis, laser detection, and spectral analysis. The four-level gain competition of Nd<sup>3+</sup> around 1060 nm severely constrains the laser power scaling of the 900-nm three-level Nd-doped fiber laser. In this work, we propose a large-mode-area Nd-doped double-layer solid-core anti-resonant fiber with a core diameter of 27 μm for generating a high-power 900-nm laser based on the resonant and anti-resonant conditions of anti-resonant fiber. The transmission properties and mode profiles of the designed fiber are analyzed theoretically by using the full-vector finite-element method combined with an optimized mesh size. By introducing the double-layer anti-resonant elements into the active fiber and optimizing the fiber structure parameters and refractive index distribution, the high-order modes are well coupled with cladding modes. Finally, the designed fiber exhibits a confinement loss below 0.1 dB/m for fundamental mode and the confinement losses of all high-order modes are greater than 10 dB/m in 880–913 nm band. More importantly, around 1060 nm, the confinement losses of all modes can reach up to 100 dB/m, which enables the designed Nd-doped fiber to effectively suppress parasitic lasing and even amplified spontaneous emission. The Nd-doped solid-core anti-resonant fiber proposed in this study shows broad application prospects in the fields of 900-nm high-power fiber laser and amplifier. The developed chemical vapor deposition process combined with stack-and-draw technology can be adopted for the fabrication of the designed fiber. In order to ensure the optical performance of the anti-resonant fiber, it is necessary to accurately control the thickness of all anti-resonant tubes, the glass composition of the active core and background area in actual fabrication.

Stationary High-Energy Pulse Generation in Er-Based Fiber Lasers via Quasi-Synchronous Gain Modulation

We demonstrate the feasibility of triggering stationary high-energy pulse generation in Er-doped fiber lasers at ~1.5 µm via quasi-synchronous gain modulation. This simple method relies upon the sine-wave modulation of pump power at a frequency slightly surpassing the intrinsic frequency spacing of longitudinal modes in the laser cavity. This was previously implemented only in Yb-doped fiber lasers at ~1.1 µm. Here, for the first time, we experimentally validate the pulse shaping capabilities of this method also in Er fiber lasers, which, unlike Yb fiber lasers, have a three-level laser energy diagram (when pumped at 0.98 µm) with a very long-lived (10 ms) upper laser level. The feasibility of the method was validated both for normal and anomalous intracavity dispersion, which was not available in previous implementations in Yb fiber lasers at ~1.1 µm. Thus, the stable generation of a regular train of discrete nanosecond pulses with an energy of up to 180 nJ was achieved in our test-bed Er fiber laser upon the quasi-synchronous sine-wave modulation of the pump power at 0.98 µm. The results of our study testify to the general applicability of this affordable and reliable method for high-energy pulse generation in various rare-earth-doped fiber lasers.

Coherent and incoherent pumping of a three-level laser

This article investigates the quantum and semi-classical aspects of a three-level atom-cavity system within the context of cavity quantum electrodynamics. The study examines the behavior of the system through a quantum perspective and a semi-classical approximation. The steady-state master equation is solved in the atom-cavity basis, resulting in a closed set of equations describing the atom’s level occupancies and the cavity’s photon number. The accuracy of the semi-classical approximation is assessed by comparing it with quantum simulations. The research analyzes the system’s behavior near the laser threshold, highlighting the interplay between semi-classical and quantum behaviors. Additionally, the conversion of the three-level atom to a two-level atom is explored under specific conditions, enabling an investigation into the weak driving limit. Quantum simulation results are used to validate the proposed approximations. This work contributes to the understanding of atom-cavity interactions and provides insights into the transition from semi-classical to quantum behavior in such systems.

Entanglement amplification by three-level laser coupled to vacuum reservoir

Entanglement amplification by three-level laser coupled to vacuum reservoir

Entanglement Correlation from a Non-degenerate Three-Level Laser with a Parametric Amplifier and Coupled to Vacuum Reservoir

The quantum properties of a non-degenerate three-level laser with the parametric amplifier and coupled to a thermal reservoir are thoroughly analyzed with the use of the pertinent master equation and stochastic differential equations associated with the normal ordering. Applying solutions of resulting differential equations, quadrature variance, the mean and variance of photon number, the photon number correlation are calculated. However, the two-mode driving light has no effect on the squeezing properties of the cavity modes. Employing the same solutions, one can also obtain anti normally ordered characteristic function defined in the Heisenberg picture. For a linear gain coefficient of (A = 100), for a cavity damping constant of K= 0:8, μ = 0.16 and for thermal reservoir nth = 0, the maximum intra cavity photon entanglement is found at steady state and at threshold to be 70%.

Microwave-assisted synthesis of praseodymium (Pr)-doped ZnS QDs such as nanoparticles for optoelectronic applications.

Praseodymium (Pr)-doped ZnS nanoparticles were synthesized using a low-cost microwave-assisted technique and investigations on their structure, morphology, optical properties, Raman resonance, dielectric properties, and luminescence were conducted. Broad X-ray diffraction peaks suggested the formation of low-dimensional Pr-doped ZnS nanoparticles with a cubic structure that was validated using transmission electron microscopy (TEM)/high-resolution TEM analysis. The energy gaps were identified using diffuse reflectance spectroscopy and it was found that the values varied between 3.54eV and 3.61eV for different samples. Vibrational experiments on Pr-doped ZnS nanoparticles revealed significant Raman modes at ~270 and ~350 cm-1 that were associated with optical phonon modes that are shifted to lower wavenumbers, indicating phonon confinement in the synthesized products. The photoluminescence (PL) spectra of all samples demonstrated that the pure and Pr-doped ZnS nanoparticles were three-level laser active materials. Energy-dispersive X-ray spectroscopy and mapping study confirmed the homogeneous presence of Pr in ZnS. TEM studies showed that the particles were of very small size and in the cubic phase. The samples had high dielectric constant values between 13 and 24 and low loss values, according to the dielectric analysis. With an increase in frequency and a change in the Pr content of ZnS, an intense peak could be seen in the PL spectra at a wavelength of 360 nm, and some other peaks observed corresponded to the transition of Pr3+ . The produced nanoparticles were appropriate for optoelectronic applications due to their short dimension, high energy gap, high dielectric constant, and low loss values.

A propagator approach to the dynamics of three-level laser with input coherent light

The squeezing and statistical features of the intracavity field produced by a three-level laser coupled to a vacuum reservoir with input coherent field are studied in this paper. Employing the propagator method, we determine the Q-function for the cavity field produced by a driven three-level laser. Using this Q-function, we have calculated the mean intensity, the quadrature variance, and the squeezing spectrum of the cavity field. It has been discovered that, despite the fact that the input coherent field improves the mean intensity of the cavity field, it has no effect on the quadrature squeezing of the cavity field. The degree of squeezing increases with the rate at which atoms are injected into a cavity and a substantial degree of squeezing is found close to the maximum initial injected atomic coherence.

Induced entanglement by three-level laser in an open cavity coupled to thermal reservoir

In this study, we have investigated the squeezing and entanglement characteristics of the light produced by three-level atoms available in an open cavity and pumped to the top level by electron bombardment at constant rate. We have obtained steady-state solutions to the quantum Langevin equations for the cavity mode operators and the equations of evolution for the expectation values of the atomic operators by employing the large-time approximation approach. The squeezing characteristics, entanglement amplification, and normalized second-order correlation function of the cavity radiation are discussed using the resulting steady-state solutions. We have seen that the light generated by the three-level laser is in a squeezed state, and the squeezing occurs in the minus quadrature. It so turns out that the maximum quadrature squeezing of the two-mode cavity light is 37.5% for n̄=0, 36.5% for n̄=0.01, and 35.5% for n̄=0.02 below the vacuum-state level. We have also established that the impact of the thermal reservoir process results in increases in the mean and variance of the photon number. Additionally, it is discovered that quadrature squeezing and entanglement are increased by the existence of spontaneous emission. This indicates that there are actually more photons fluctuating in the cavity. It is found that the squeezing and entanglement in the two-mode light are directly related. As a result, an increase in the degree of squeezing directly leads to an increase in the degree of entanglement and vice versa. This shows that, whenever there is squeezing in the two-mode light; an entanglement exists in the system.

Gaussian quantum steering in a nondegenerate three-level laser

Steering is a type of nonseparable quantum correlation, where its inherent asymmetric feature makes it distinct from Bell nonlocality and entanglement. In this paper, we investigate quantum steering in a two-mode Gaussian state [Formula: see text] coupled to a two-mode vacuum reservoir. The mode [Formula: see text] ([Formula: see text]) is emitted during the first (second) transition of a nondegenerate three-level cascade laser. By means of the master equation of the state [Formula: see text], we derive the analytical expression of the steady-state covariance matrix of the modes [Formula: see text] and [Formula: see text]. Using realistic experimental parameters, we show that the state [Formula: see text] can exhibit asymmetric steering. Furthermore, by an appropriate choice of the physical parameters of the state [Formula: see text], we show that one-way steering can be achieved. Essentially, we demonstrate that one-way steering can, in general, occur only from [Formula: see text]. Besides, we perform a comparative study between the steering of the two laser modes and their Gaussian Rényi-2 entanglement. As a result, we found that the entanglement and steering behave similarly in the same circumstances, i.e. both of them decay under dissipation effect; moreover, they can be well enhanced by inducing more and more quantum coherence in the state [Formula: see text]. In particular, we found that the steering remains always less than the Gaussian Rényi-2 entanglement.

Entanglement Dynamics Induced by a Three-Level Laser Coupled to the Squeezed Vacuum Reservoir

We have studied the squeezing and entanglement properties of the light induced by a three-level laser coupled to the squeezed vacuum reservoir. Applying the pertinent master equation, we have obtained the evolution equations for the cavity mode variables. Using the solutions of the resulting equations, the squeezing properties, entanglement amplification, and the normalized second-order correlation function of the cavity radiation are described. We have seen that the light generated by a three-level laser is in a squeezed state, and the squeezing occurs in the plus quadrature. In addition, we have also established that the effect of the squeezed parameter increases the mean and variance of the photon number. It is found that the squeezing and entanglement in the two-mode light are directly related. As a result, an increase in the degree of squeezing directly leads to an increase in the degree of entanglement and vice versa. This shows that, whenever there is squeezing in the two-mode light, there exists an entanglement in the system.

Initial mean cavity photons and driving field effects on the non-classical features of cavity field from a three-level laser

Initial mean cavity photons and driving field effects on the non-classical features of cavity field from a three-level laser

Light Entanglement from a Non-Degenerate Three-Level Laser with a Parametric Amplifier and Coupled to a Thermal Reservoir

Light Entanglement from a Non-Degenerate Three-Level Laser with a Parametric Amplifier and Coupled to a Thermal Reservoir

Entangled Photon Generation From a Three-Level Laser with a Parametric Amplifier and Coupled to a Thermal Reservoir

In this article we study squeezing and statistical properties of light producing by a non-degenerate three-level laser with the parametric amplifier and coupled to a thermal reservoir. With the aid of master equation, we obtain stochastic differential equations. Applying solutions of resulting differential equations, we calculate quadrature variance, the mean and variance of photon number, the photon number correlation. However, the two-mode driving light has no effect on the squeezing properties of the cavity modes. On the other hand, parametric amplifier and thermal reservoir increase the mean and variance of photon number. Furthermore, employing the same solutions, we also obtain anti normally ordered characteristic function defined in the Heisenberg picture. For a linear gain coefficient of (A = 100), for a cavity damping constant of K= 0:8,μ = 0 and for thermal reservoir ¯ nth = 0 ,the maximum intra cavity photon entanglement is found at steady state and at threshold to be 60%.