Journal of Russian Laser Research最新文献

We report on a passively Q-switched 2 μm Ho :YAG ceramic laser, using pure GaAs as a saturable absorber. At an absorbed pump power of 1.28 W, the highest pulse repetition rate, shortest pulse width, largest single pulse energy, and highest peak power are measured to be 295 kHz, 83 ns, 1.49 μJ and 17.95 W, respectively. To the best of our knowledge, this is the first 2 μm passively Q-switched laser with a pure GaAs absorber, the three-photon absorption is believed to play an important role in the saturable absorption process.

We show that by minor modification of the previously proposed procedure for the generation of near-coherent states, one can produce “near states” even from a mixed input state. In this study, we consider this procedure as a conditional quantum-state transformation and find the explicit form of the non-unitary transformation operator. We demonstrate that even in mixed states, this quantum process can produce nonclassical states with a smooth non-positive P-function.

Using the Lie-algebraic approach, we develop the theory of generation of squeezed states of light in nonstationary parametric processes of the light interaction with a medium with the quadratic and quartic nonlinearities. The exact solution for the variance of the quadrature component of the field strength is obtained in the case of the quadratic parametric process with the SU(1, 1) dynamical symmetry. We show that decay of the field mode in this processes may have strong impact on squeezing. The solution for the standard deviation of the field strength in the case of the quartic parametric process with the approximated ({mathcal{L}}_{5}) dynamical symmetry is obtained in the first order of smallness with respect to the nonlinearity parameter.

The annular array Airy beam (AAAB) possesses excellent optical properties, and it exhibits great potential in optical particle manipulation, light bullet, and so on. When the power of the laser system is relatively high, the B-integral greatly affects the generation and transmission of AAABs. We numerically study the nonlinear propagation of AAABs based on the Schrödinger equation. The variation of the maximum peak intensity of the AAAB with the nonlinear coefficient at different parameters are discussed. The influence of the truncation coefficient, lateral offsets, scale factor, and rotation factor on the AAAB affected by B-integral are also taken into consideration. We show that the AAAB gradually evolves into solitons in the transmission process as the nonlinear coefficient increases. The intensity of AAAB is altered due to the B-integral, and the effect of the B-integral on the transmission of the AAAB cannot be ignored. The research results will be a great boost to the application of the AAAB in biomedicine, particle manipulation, and various other fields.

In this paper, we investigate the continuous-wave lasing characteristics of Ho :GdVO₄ crystal under diode-pumping conditions. Using a 1.0 at.%-doped crystal, we obtain the maximum output power equal to 9.0 W at 2047.9 nm, with an absorbed pump power of 28.2 W. The slope efficiency and optical efficiency measured with respect to the absorbed pump power are 50.7% and 31.9%, respectively. In addition, we estimate the beam quality factor at the maximum output level to be about 1.8.

We present the expression of a partially coherent sine beam and derive the propagation equations of such a beam in non-Kolmogorov turbulence. The intensity profiles of the beam in non-Kolmogorov turbulence are simulated and analyzed. The obtained results show that the sinusoidal array profile is destroyed by non-Kolmogorov turbulence and beam parameters during the propagation, and the intensity profile of such a beam becomes a sheet, when a and b are set. The array profile properties of partially coherent sine beams introduced here display new properties, and these beams help free space optical communications.

In this paper, we study quantum correlations in a Heisenberg XYZ model with the Dzyaloshinskii–Moriya interaction based on the Sharma–Mittal quantum discord and its limiting cases. The results obtained show that the Sharma–Mittal quantum discord is a faithful quantifier and that the Dzyaloshinskii–Moriya interaction significantly enhances quantum correlations within the bipartite system. In contrast, temperature has the opposite effect, leading to a reduction in the quantity of quantum correlations in the system.

We formally generate picosecond laser pulses in an Erbium-doped fiber laser (EDFL) by incorporating a new type of a saturable absorber (SA) with Chromium–Titanium–Aluminum carbide (Cr₂TiAlC₂). The SA film is prepared by a casting method, using polyvinyl alcohol (PVA) as a host. The novel ultrafast laser operates at 1559.96 nm; the laser pump power range is 164 – 305 mW. Using a 90 : 10 output coupler, the designed laser produces a pulse duration of 2.04 ps and a repetition rate of 1.855 MHz. We obtain a maximum output power of 3.2 mW and a pulse energy of 1.72 nJ at a maximum laser pump power of 305 mW. To the best of our knowledge, this is the first time that a Cr₂TiAlC₂-based SA is used to produce ultrashort laser pulses.

We present a coiled and tapered graded-index few-mode-fiber (FMF) polarization controller (PC) as a saturable absorber (SA) in an all-fiber laser. We obtain the 845 fs ultrashort pulse with a signal-to-noise ratio (SNR) of 65 dB, using a tapered graded-index FMF of 40 cm in the cavity. The spectrum is centered at 1588.2 nm with a 3 dB spectral bandwidth of 4.04 nm. Furthermore, a Q-switched mode-locked state is observed between 140 and 360 mW of the pump power in the cavity. The results further demonstrate the application of a coiled and tapered graded-index FMF PC as a SA for stable high-energy ultrashort pulse formation and provide a technical method for generating ultrashort pulses.

In this paper, we present a finite element model that utilizes simulation software to simulate the process of moving nanosecond pulsed laser cleaning on the surface paint layer of 2A12 Aluminum alloy. The objective is to analyze the impact of different laser parameters on the distribution of temperature field within both the paint layer and the substrate surface. Furthermore, we perform experimental validation to verify the findings. The results assume that both laser power and scanning speed influence the outcomes of the cleaning process. At a constant scanning speed, the maximum temperature of both the paint surface and the substrate surface linearly increases with rising laser power. In contrast, at a fixed laser power, the scanning speed influences cleaning outcomes through spot overlap, and the surface temperature of the paint layer rises as the scanning speed decreases. The optimum cleaning effect, with a surface roughness (Ra) of 1.0139 μm, is achieved at a scanning speed of 2500 mm/s and a laser power of 30 W. The surface roughness exhibits first a decrease and then increase pattern with rising laser power. These findings offer valuable insights into process parameters for nanosecond pulsed laser cleaning of surface paint layers on Aluminum alloy.