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We propose and analyze theoretically a double magnetic plasmon resonance nanolaser, in which ytterbium-erbium codoped material is used as the gain medium. Through design of the double magnetic resonance modes, pumping light (980 nm) can be resonantly absorbed and laser light (1550 nm) can be resonantly generated simultaneously. We introduce a set of rate equations combined to describe the operation of the laser and predict the lasing condition. According to our calculations, the disadvantage that pumping light is difficult to be absorbed by a thin slab of gain materials can be overcome. [ABSTRACT FROM AUTHOR]

This paper is aimed at the explanation of mechanisms responsible for plasma jet formation: the radiative cooling of ablative plasma and the influence of target irradiation geometry. The experiment was carried out with the Prague Asterix Laser System (PALS) iodine laser. A three-frame laser interferometer and an x-ray streak camera were used as two main diagnostic tools. These investigations have shown that the geometry of target irradiation is crucial, an annular target irradiation being necessary for plasma jet formation. Thus the role of radiative cooling in the plasma jet forming seems to be negligible. [ABSTRACT FROM AUTHOR]

This letter discusses the effect of nitric oxide on gain and output power of a pulser-sustainer discharge excited oxygen iodine laser. Adding small amounts of NO to the laser mixture (a few hundreds of ppm) considerably increases gain and output power due to (i) O atom titration and resultant slower I* atom quenching and (ii) improved stability of the dc sustainer discharge, which allows stable operation at significantly higher discharge powers. Gain on the 1315 nm iodine atom transition and laser power in the M=3 transverse laser cavity are 0.049%/cm and 1.24 W, at a flow temperature of T=100 K. [ABSTRACT FROM AUTHOR]

A multikilowatt chemical oxygen-iodine laser (COIL) using molecular iodine generated chemically as the iodine source was developed and tested. The COIL, with a gain length of 26.5 cm, was energized by a square pipe-array jet singlet oxygen generator (JSOG), with a nozzle bank having a designed Mach number of 2.5. The JSOG, operating without a primary buffer gas, has a much better operation stability during basic hydrogen peroxide pumping circulations. Iodine injectors/nozzles made of polyimide were used. An output power of 7.8 kW and a chemical efficiency of 24.5% were achieved with a chlorine flow rate of 353 mmole/s. [ABSTRACT FROM AUTHOR]

Very low threshold current densities are reported from buried heterojunction quantum-cascade laser (QCL) grown by metal-organic chemical-vapor deposition at an emission wavelength of 5.07 μm. Continuous-wave operation threshold current densities as low as 0.75 and 0.83 kA/cm2, efficiencies of 1079 and 879 mW/A, and total output powers of 116 and 74 mW have been achieved for temperatures of 288 and 298 K. These cw threshold current densities are lower than all previously reported values for Fabry-Pérot QCLs. Internal loss as low as 1.84 cm-1 has been extracted; also the lowest value thus far reported in the literature. [ABSTRACT FROM AUTHOR]

Direct measurements of the dissociation of I2 molecules at the optical axis of a supersonic chemical oxygen-iodine laser (COIL) as a function of I2 flow rate were carried out. This enabled us to determine the number of consumed O2(1Δ) molecules per dissociated I2 molecule. The number depends on the experimental conditions: it is 4.2±0.4 for typical conditions and I2 densities applied for the operation of the COIL, but increases at lower I2 densities. Possible dissociation mechanisms consistent with our results are discussed and the importance of dissociating I2 prior to its mixing with O2(1Δ) is stressed. [ABSTRACT FROM AUTHOR]

Continuous-wave single-mode emission near λ=3.42 μm is obtained from a distributed-feedback (DFB) interband cascade laser. The low-loss DFB mode in the 15-μm-wide ridge is resonant with the gain peak at 110 K, where the maximum single-mode output power is 3 mW. The instrument-limited linewidth is ≤=0.5 Å, and the wavelength is linearly tunable over a 4 nm range by varying the temperature from 110 to 125 K (0.28 nm/K), or over 0.6 nm by varying the current from 60 to 83 mA (0.031 nm/mA) [ABSTRACT FROM AUTHOR]

Improving the chemical efficiency of the supersonic chemical oxygen-iodine laser (COIL) is a key issue for the design of devices for both defense and industrial applications. Efficiencies around 30% for the supersonic COIL have been the state of the art in the last decade. Here, we report the achievement of a record (40%) for the chemical efficiency of the supersonic COIL. More specifically, we show that by carefully studying and optimizing the operation of the chemical generator, the mixing of heavy and light molecules in the gas phase and the optical extraction efficiency, we have approached the theoretical limit for the chemical efficiency. [ABSTRACT FROM AUTHOR]

We report on a highly efficient supersonic chemical oxygen–iodine laser (COIL), with supersonic mixing of iodine and oxygen. Output power exceeding 0.5 kW with chemical efficiency of ∼33% was obtained in a 5-cm gain length for Cl[sub 2] flow rate of 17 mmole/s. A 33% efficiency is the highest reported chemical efficiency of any supersonic COIL. Comparison between different mixing schemes shows that, for supersonic mixing, the output power and chemical efficiency are about 20% higher than for transonic mixing scheme. The optimal conditions for the efficient operation are investigated. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Studies the high-pressure, high-efficiency operation of a chemical oxygen-iodine laser. Direct utilization in the laser cavity of singlet delta oxygen generated by a liquid-type singlet oxygen generator; Ratio of excited iodine to the ground state iodine after dissociation; Laser output as a function of mirror transmittance.

Reports on the measurements of the gain and temperature in the resonator of a supersonic chemical oxygen-iodine laser with transonic injection of iodine. Conditions corresponding to the maximum chemical efficiency; Gain as a nonmonotonous function of the iodine flow rate; Use of dependencies in the calculation of the iodine dissociaton fraction.

Examines the behavior and lateral optical models of narrow-stripe gain-guided nitride laser diodes using waveguide simulations and incorporating the complex refractive indices associated with optical gain. Threshold current; Explanation for the rapid increase in threshold when stripe width becomes less than five micrometers; Intrinsic gain-current characteristic of the material.

Presents an efficient supersonic chemical oxygen-iodine laser, energized by a jet-type singlet oxygen generator. Attainment of chemical efficiency; Result of power measurements for the different positions of the optical axis of the resonator; Effect of increasing the basic hydrogen peroxide flow rate inside the generator.

Examines the high-resolution spectroscopy of overlapping lines with disparate oscillator strengths. Application of high-order derivative absorption spectroscopy; Use of tunable diode lasers with the absence of wavelength-resolution apparatus; Impact of the method on monitoring of specie properties and line-shape profile investigation.

High-efficiency and high-energy operation of HF chemical lasers was simultaneously realized using a low pressure mixture of H2/F2/O2/MoF6 initiated by an intense electron beam. The addition of small amounts of MoF6 gas to the mixture of H2/F2/O2 resulted in an increase in laser output energy and electrical and chemical efficiencies. A HF laser energy obtained from a mixture containing 17.9 Torr of MoF6 was 3.7 kJ (136 J/l) with a pulse width of 190 ns full width at half-maximum. The corresponding electrical efficiency and chemical efficiency are 189% and 15.2%, respectively, with a low pressure (362.4 Torr) mixture of H2/F2/O2/MoF6=30/242/72.5/17.9 Torr. [ABSTRACT FROM AUTHOR]

High electrical and high chemical efficiencies were simultaneously achieved for the multikilojoule HF chemical laser using a Lambda-type (inclined type) electron beam initiation scheme. The optimum addition of NF3 or SF6 fluorine donor could increase both efficiencies and could reduce the total pressure of the laser gas mixture. The laser output obtained from the low-pressure mixture of H2/F2/O2/NF3=30/208/62.5/70 (Torr) was 4.5 kJ in a 50-ns FWHM pulse width with an electrical laser efficiency of 226% and a chemical efficiency of 18.5%. [ABSTRACT FROM AUTHOR]

cw operation of a chemical oxygen-iodine laser (COIL) using ICl as a source of atomic iodine at powers approaching 120 W is reported. The vapor pressure of ICl is higher than the vapor pressure of the more conventional I2 fuel usually used in COIL. More iodine can therefore be delivered to the laser gas stream using ICl than can be delivered using I2. This concentration increase is advantageous for low-temperature operation at high partial pressures of the atomic iodine source. [ABSTRACT FROM AUTHOR]

Investigates neodymium fluorescence excitation and emission spectra in neodymium:magnesium oxide:lithium niobate oxide lasers. Identification of sites responsible for two infrared laser lines; Excitation of the identified site; Necessity of pumping each laser line with light of different wavelengths.

Demonstrates that the stable index-guided operation of variable stripe strained-layer InGaAs-GaAs-AlGaAs lasers achieved by MeV oxygen implantation-induced disorder of the active region. Fabrication of stripe geometry lasers by oxygen implantation; Comparison with unimplanted, oxide-defined stripe lasers fabricated from the same wafer; Emission characteristics.

Reports on the fabrication of a indium gallium arsenide (InGaAs)/aluminum gallium arsenide (AlGaAs) strained-layer distributed-feedback grating-surface-emitting lasers with a buried grating structure. Device components; Threshold current density; Measured near-field and far-field radiation patterns.

Efficient production of singlet delta oxygen in a bubble singlet oxygen generator (BSOG) under the influence of centrifugal acceleration, 136 g, has been obtained. An output power of 770 W with chemical efficiency of 25.6% has been achieved in a small-scale, supersonic chemical oxygen-iodine laser supplied by the centrifugal BSOG. The ratio of the output power to the basic hydrogen peroxide volumetric flow rate was 4.3 KJ/liter. Efficient chemical oxygen-iodine laser (COIL) operation with the centrifugal BSOG demonstrates the potential for mobile COIL applications. [ABSTRACT FROM AUTHOR]

A new visible chemical laser analogous to excimer lasers in lasing principle has been studied. Laser oscillation has been observed in the red spectral range. To our knowledge this is the first demonstration of chemical laser oscillation in the visible spectral range. [ABSTRACT FROM AUTHOR]