Journal of Russian Laser Research最新文献

The master equation for a harmonic oscillator (HO) of frequency (omega_o), driven strongly and resonantly, and dissipated by an ohmic Markovian broadband squeezed vacuum (SV) radiation reservoir is explicitly derived. An intensive driving field with amplitude strength (Omegasimomega_o) induces alterations in the strength field: (OmegarightarrowOmega[1+igamma^{prime}(omega_o)]), where (gamma^{prime}(omega_o)=frac{dgamma(omega_o)}{domega_o}) with (gamma(omega_o)) being the damping constant of the HO. Hence, the average values of the system variables are dependent on the spectral density of the radiation reservoir modes, which is determined by the factor (gamma^{prime}(omega_o)). Sub-Poissonian photon statistics of the emitted radiation is identified via the negativity of the Mandel Q_M factor. In the steady state, isoline contour plots of (Q_M(infty)) in different planes of the SV phase ((varphi)) and the ohmic parameters indicate that symmetric regions where (Q_M(infty)<0) are shifted and become asymmetric with respect to (varphi=pi) in the intense field case (i.e. (gamma^{prime}(omega_o)neq0)).

In this experiment, we demonstrate the application of a Molybdenum ditelluride (MoTe₂) thin film as a saturable absorber (SA) for inducing Q-switching in the 2.0 µm region. The fabrication of the MoTe₂ involved a bottom-up approach, where a three-electrode configuration was employed for electrodeposition onto a conductive film substrate. This method offers distinct advantages over conventional top-down approaches, as it proves to be more cost-effective and provides greater control over film thickness through precise manipulation of deposition time. The MoTe₂ thin film, nestled between two fiber ferrules, is seamlessly integrated into a Thulium-doped fiber laser (TDFL) cavity. Through this setup, we successfully realized a stable switched laser operating at 1910.3 nm, boasting a repetition rate of 4.61 kHz and a corresponding pulse width of 3.05 µs. Notably, the achieved pulse energy measured at 4.158 nJ, while the output power reached 0.173 mW under a maximum pump power of 677.04 mW at 1552 nm. These results indicate the promising potential of MoTe₂ thin films as efficient and reliable SAs for advancing Q-switched fiber laser technology in the mid-infrared spectral regime.

One-dimensional photonic crystal (1D PhC) biosensors are emerging as powerful tools in the fight against diseases like colorectal cancer, a disease affecting millions globally. These innovative sensors exploit a unique property—their ability to detect bio molecular interactions by measuring changes in light. In this paper, we present a novel 1D PhC biosensor design with ultra-high sensitivity for detecting colorectal disorders. The sensor operates by monitoring the defect mode of the photonic crystal through a detailed analysis of light transmittance profiles obtained from excised colorectal tissue samples. The proposed design, consisting of a defect layer sandwiched between two identical periodic layers: [ (mathrm {air} mid (text{Si} mid text{SiO}_{2})^N mid mathrm {Defect},mathrm {layer} mid (text{Si} mid text{SiO}_{2})^N mid) air], is optimized to a ternary structure, where a thin polystyrene (PS) film is inserted between silicon (Si) and silicon dioxide (SiO₂) layers. This innovation significantly enhances the sensitivity compared to traditional binary structures. We employ the transfer matrix method to investigate the transmission spectra. Our results demonstrate that the ternary 1D biosensor exhibits an exceptional sensitivity of 1821 nm/RIU and a quality factor of 2000, far exceeding those of the binary sensor. This remarkable improvement can be attributed to the introduction of the polystyrene layer, which creates a gradual decrease in the refractive index profile. Consequently, a larger portion of light interacts with the analyte, leading to a stronger light–matter interaction. This translates to a highly sensitive detection method, where the resonant mode will be more sensitive and a significant shift in the near-infrared region is observed due to changes in the refractive index of colorectal tissue. The proposed biosensor offers several advantages—it facilitates label-free detection with real-time analysis, boasts a compact and cost-effective design, and is straightforward to fabricate due to its nanoscale size. Furthermore, its high sensitivity makes it a promising platform for various biomedical sensing applications beyond colorectal cancer detection, such as the detection of other biomarkers, monitoring drug delivery, or studying cellular interactions.

The notion of an infinite set of orthogonal conditional probability distributions describing quantum system states is introduced. The example of such orthogonal probability distributions is considered being associated with quantum oscillator states. The connection with separable and entangled probability distributions is discussed in the case of the probability distributions describing the oscillator energy states.

We carry out ab initio multi-reference calculations of the potential energy curves of 36 lowermost electronic states of NeAr⁺ molecular ions. In addition to the regular states, accurate data on the states with the charge transfer character are obtained. The oscillator strengths of the dipole-allowed transitions originating from first three electronic states are reported for the first time. The results presented are important for the kinetic modeling of the operation of gas lasers and plasma-based UV radiation sources, including ArF excimer laser.

The structure of Fe²⁺ ion highly excited states in ZnSe is studied by means of low-temperature photoluminescence and photoluminescence excitation techniques. It is established that several luminescence bands in the visible spectrum region are due to Fe²⁺ intracenter transitions. Spectral features detected at a temperature of 5 K are identified within the framework of crystal field theory calculations and fine structure analysis of electron levels using group theory.

The diode-pumped continuous-wave (CW) tunable single- and dual-wavelength Nd:LuYAG lasers operation at 1.4 µm was demonstrated for the first time. By rotating an intracavity Lyot filter, three tuning wavelengths at 1419, 1435, and 1446 nm were obtained, respectively. At an absorbed pump power of 19.2 W, a maximum output power of 2.76 W at 1419 nm was realized with a slope efficiency of 17.3% and an optical conversion efficiency of 14.4%. Additionally, three pairs of tunable dual wavelength lasers operating at 1419 and 1435 nm, 1419 and 1446 nm, and 1435 and 1446 nm were also achieved by rotating the Lyot filter, respectively. At an absorbed pump power of 19.2 W, the highest total output power at 1419 and 1435 nm was 2.61 W with the total optical conversion efficiency of 13.6%.

We report for the first time a diode-pumped continuous-wave (CW) orthogonally polarized dual-wavelength Nd:LiYF₄ (Nd:YLF) laser at 1072 and 1074 nm on ⁴F(_{3/2}to{}^{4}text{I}_{11/2}) transition. By rotating the birefringent filter (BF) in the cavity, the gain and loss of the two wavelengths of the orthogonal polarization are balanced. At an incident pump power of 30 W, a dual-wavelength laser operating at 1072 nm in (pi)-polarization and 1074 nm in (sigma)-polarization with 7.0 W of total output power is obtained. Additionally, by rotating the BF simultaneous dual-wavelength lasers operating at 1068 and 1072 nm, 1068 and 1074 nm are also obtained, respectively.

We analyze the optical bistability (OB) and absorption properties of a weak probe field in a five-level M‑type atomic system confined in a unidirectional ring cavity. We find that the threshold of OB and the absorption of the probe field in the M‑type atomic system can be controlled by adjusting the intensity and the detuning of the coupling fields. Finally, by comparison with previous results in (Lambda)- and N‑type atomic systems under similar conditions, we show that the OB threshold in this case is lower than that for (Lambda)- and N‑types.