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A full-dimensional ab initio potential energy surface for the H2–HF van der Waals complex was constructed by employing the coupled-cluster singles and doubles with noniterative inclusion of connected triples with augmented correlation-consistent polarised valence quadruple-zeta basis set plus bond functions. Using the improved coupled-states approximation including the nearest neighbor Coriolis couplings, we calculated the state-to-state scattering dynamics for pure rotational and ro-vibrational energy transfer processes. For pure rotational energy transfer, our results showed a different dynamical behavior for para-H2 and ortho-H2 in collision with hydrogen fluoride (HF), which is consistent with the previous study. Interestingly, some strong resonant peaks were presented in the cross sections for ro-vibrational energy transfer. In addition, the calculated vibrational-resolved rate constant is in agreement with the experimental results reported by Bott et al. These dynamics data can be further applied to the numerical simulation of HF chemical lasers. [ABSTRACT FROM AUTHOR]

The results of three-dimensional computational fluid dynamics model calculations are compared to available experimental results [V. D. Nikolaev et al., IEEE J. Quantum Electron. 38, 421 (2002)]. It is shown that the model is applicable to high pressure, ejector type chemical oxygen-iodine laser (COIL), reasonably reproducing the measured gain, temperature, static pressure, and gas velocity. A previous model, which included I2(A′3Π2u), I2(A3Π1u), and O2(a1Δg,v) as significant intermediates in the dissociation of I2 [K. Waichman et al., J. Appl. Phys. 102, 013108 (2007)], reproduced the measured gain and temperature of a low pressure supersonic COIL. The previous model is complemented here by adding the effects of turbulence, which play an important role in high pressure COILs. [ABSTRACT FROM AUTHOR]

The mechanism by which I2(B3Π0) is excited in the chemical oxygen-iodine laser was studied by means of emission spectroscopy. Using the intensity of the O2(b1Σ,υ′=0)→O2(X3Σ,υ″=0) band as a reference, I2(B3Π0) relative number densities were assessed by measuring the I2(B3Π0,υ′)→I2(X1Σ,υ″) emission intensities. Vibrationally excited singlet oxygen molecules O2(a1Δ,υ′=1) were detected using infrared emission spectroscopy. The measured relative density of O2(a1Δ,υ′=1) for the conditions of a typical oxygen-iodine laser medium amounted to ∼15% of the total O2(a1Δ) content. Mechanisms for I2(B3Π0) formation were proposed for both the I2 dissociation zone and the region downstream of the dissociation zone. Both pumping mechanisms involved electronically excited molecular iodine I2(A′3Π2u, A3Π1u) as an intermediate. It is proposed that in the dissociation zone the molecular iodine A′3Π2u and A3Π1u states are populated in collisions with vibrationally excited singlet oxygen molecules O2(a1Δ,υ′), whereas in the downstream region of the dissociation zone those intermediate states are populated by the atomic iodine recombination process. I2(B3Π0) is subsequently formed in collisions of I2(A′3Π2u, A3Π1u) with singlet oxygen. We also demonstrated that I2(B3Π0) does not participate measurably in the I2 dissociation process, and that energy transfer from O2(b1Σ) does not excite I2(B3Π0) to a significant degree. [ABSTRACT FROM AUTHOR]

Chemical oxygen-iodine lasers (COILs) oscillate on the 2P1/2→2P3/2 transition of atomic iodine at 1.315 μm by a series of excitation transfers from O2(1Δ). In electrically excited COILs (eCOILs), the O2(1Δ) is produced in a flowing plasma, typically He/O2, at a few to tens of Torr. Many system issues motivate operating eCOILs at higher pressures to obtain larger absolute densities of O2(1Δ) for a given yield and to provide higher back pressure for expansion. In this paper, we discuss results from a computational investigation of O2(1Δ) production in flowing plasmas sustained at moderate pressures (≤50 Torr). Power deposition and flow rates were scaled such that in the absence of second order effects, yield should be constant and absolute O2(1Δ) production should scale linearly with pressure. We found in many cases that absolute O2(1Δ) production scaled sublinearly with pressure. Ozone is found to be one of the major quenchers of O2(1Δ) and its production increases with pressure. Gas heating also increases with increasing pressure due to exothermic three-body reactions. The gas heating reduces O3 production, increases O3 destruction and, for certain conditions, restores yields. With increasing pressure and increasing absolute densities of atomic oxygen and pooling reactions of O2(1Δ), quenching by these species also becomes important, though the influence of O-atom quenching can be controlled by managing the density of O atoms with additives. The yield of O2(1Δ) is also determined by discharge stability which becomes problematic at higher pressure. [ABSTRACT FROM AUTHOR]

The development of high-energy lasers requires optical windows capable of handling megajoule beam energies without compromising the system’s performance. Calcium fluoride (CaF2) has been identified as a prime candidate for windows operating at chemical laser wavelengths due to very low bulk absorption and exceptionally small thermal lensing coefficients; it is, however, vulnerable to structural failure owing to poor mechanical strength characteristics and a large thermal stress factor. It is, therefore, essential to properly assess the ultimate potential of this material, which we attempt to do here in the following manner: (a) We assemble reliable numbers for all pertinent properties of (111)-oriented CaF2 single crystals and polycrystalline isotropic aggregates (PIAs), such as fusion-cast CaF2, which requires addressing issues relating to the elastic properties, the stress-optic coefficients, and the flexural strength. (b) We provide correct analytical expressions for evaluating the impact of pressure- and beam-induced effects on wave-front phase distortions and mechanical failure modes, taking advantage of a previous investigation [J. Appl. Phys. 98, 043103 (2005)]. (c) We perform detailed calculations on “model” windows made of either (111)CaF2 or (PIA)CaF2 that transmit optimally truncated Gaussian beams at wavelengths of 1.15 and 3.39 μm, for run times such that lateral heat conduction and surface cooling can be ignored. Our main conlusions are as follows: (a) With CaF2 windows thermal lensing, as measured in terms of the Strehl ratio and on assuming coating absorptances of no more than 3×10-5, is of no consequence in the sense that catastrophic failure may occur at fluence levels way below the threshold for optical distortion. (b) Evidence of a poor Weibull shape factor (m≃3.5) degrades the design safety margins, which requires operating at peak intensities of no more than 100 kW/cm2 to achieve optimum on-target fluences. (c) Regarding the issue of (111)CaF2 vs (PIA)CaF2, we note that fusion-cast material outperforms single crystals based on the figure of merit for distortion, as well as fracture and yield strengths, but contrary to (111)-oriented material, it exhibits birefringence that may rule out its use if depolarization is of concern. [ABSTRACT FROM AUTHOR]

In chemical oxygen iodine lasers (COILs), oscillation at 1.315 μm in atomic iodine (2P1/2→2P3/2) is produced by collisional excitation transfer of O2(1Δ) to I2 and I. Plasma production of O2(1Δ) in electrical COILs (eCOILs) eliminates liquid phase generators. For the flowing plasmas used for eCOILs (He/O2, a few to tens of torr), self-sustaining electron temperatures, Te, are 2–3 eV whereas excitation of O2(1Δ) optimizes with Te=1–1.5 eV. One method to increase O2(1Δ) production is by lowering the average value of Te using spiker-sustainer (SS) excitation where a high power pulse (spiker) is followed by a lower power period (sustainer). Excess ionization produced by the spiker enables the sustainer to operate with a lower Te. Previous investigations suggested that SS techniques can significantly raise yields of O2(1Δ). In this paper, we report on the results from a two-dimensional computational investigation of radio frequency (rf) excited flowing He/O2 plasmas with emphasis on SS excitation. We found that the efficiency of SS methods generally increase with increasing frequency by producing a higher electron density, lower Te, and, as a consequence, a more efficient production of O2(1Δ). [ABSTRACT FROM AUTHOR]

Chemical oxygen-iodine lasers (COILs) have promising applications due to their high efficiency and ease of scaling to multikilowatt powers. Recent research has focused on pumping the iodine with O2(1Δ) produced by electric discharges. In a previous work, a global model was used to develop reaction mechanisms and determine the specific energy deposition (eV/O2) required to obtain high O2(1Δ) yields for electric discharge COILs. Experiments have recently achieved positive laser gain and oscillation with these energy depositions and have highlighted the importance of axial expansion of the plasma in optimizing excitation of the O2(1Δ). In this work, the consequences of axial transport on O2(1Δ) yields have been computationally investigated in flowing He/O2 plasmas at a few Torrs using a one-dimensional plasma hydrodynamics and kinetics model. We show that the experimentally observed extension of the plasma glow upstream and downstream of the electrodes is due to electron diffusion and capacitive coupling of the radio-frequency power source. We also show that ≈50% higher O2(1Δ) yields can be achieved with a pulsed discharge combined with continuous-wave discharge. [ABSTRACT FROM AUTHOR]

A six-temperature kinetic model for a CO2-N2-He system is used to describe the dynamic processes of a mechanical Q-switched CO2 laser that is set up using a fast chopper. We put special emphasis on the effect of dynamical parameters on the laser intensity. It takes into account the effects of electrical excitation, energy transfer processes, thermal energy transport, as well as the dissociation of CO2 molecules and rotational relaxation of rotational levels. The results calculated are in satisfactory agreement with experimental data. [ABSTRACT FROM AUTHOR]

In conventional chemical oxygen-iodine lasers (COIL) the 1.315 μm transition in atomic iodine is pumped by a sequence of reactions of I2 and I with O2(1Δ) which is generated using liquid chemistry. Ongoing studies are investigating means to produce the O2(1Δ) precursor with an electric discharge (eCOIL) to enable a totally gas phase system. Due to the thermodynamic and power loading requirements, the plasma in eCOIL systems is sustained in a flow of a rare-gas diluent and the O2. In previous investigations, the scaling of production of O2(1Δ) was investigated using global-kinetics and one-dimensional (1D) models. It was found that the production of O2(1Δ) scaled linearly with energy deposition for moderate loadings (a few eV/O2 molecule). In this paper, these previous investigations are extended to two-dimensions using a plasma hydrodynamics model. The goal of this investigation is to determine if multidimensional considerations affect energy scalings for production of O2(1Δ). We found that O2(1Δ) production generally does scale linearly with energy loading, however, the saturation of O2(1Δ) production occurs at lower-energy loadings than predicted with global and 1D models. This trend is a result of the more accurately depicted and more localized energy deposition afforded by the two-dimensional model, and emphasizes the need for volumetrically uniform power deposition to optimize O2(1Δ) production. [ABSTRACT FROM AUTHOR]

We report on a detailed parametric study of the extremely efficient supersonic chemical oxygen-iodine laser recently developed in our laboratory [V. Rybalkin, A. Katz, B. D. Barmashenko, and S. Rosenwaks, Appl. Phys. Lett. 85, 5851 (2004)]. At the early stage of operation, 40.0% efficiency was measured for 1 s followed by a sustained 35.5% chemical efficiency for 20 s. The power and spatial distributions of the gain and temperature across the flow were measured for different supersonic nozzles with both staggered and nonstaggered iodine injection holes, different injection locations along the flow and nozzle throat heights. The effects of the partial pressure of O2 and the residence time of the flow in the generator, as well as the heating of the nozzle, are discussed and shown to be crucial in attaining this high efficiency. By carefully studying and optimizing the operation of the chemical generator, 0.73 yield of singlet oxygen was obtained for conditions corresponding to the highest efficiency. [ABSTRACT FROM AUTHOR]

We demonstrate molecular orientation by using phase-controlled two-color ω+2ω laser pulses with an intensity of 1.0×10[sup 12] W/cm[sup 2] and a pulse duration of 130 fs. The orientation of three iodine-containing molecules (IBr, CH[sub 3]I, and C[sub 3]H[sub 5]I) was monitored by the directional asymmetries of the photofragment angular distribution in dissociative ionization. In all three molecules, the directional asymmetry showed an oscillating behavior dependent on the relative phase difference between ω and 2ω pulses. The phase dependence of the directional asymmetry observed in iodine ions and counterpart ions were out of phase with each other. This result shows that a phase-controlled ω+2ω optical field discriminates between parallel and antiparallel configurations of aligned molecules that have a permanent dipole. This method performed well because (1) molecular orientation can be achieved by all-optical fields; (2) the direction of orientation is easily switched by changing the sign of the quantum interference; and (3) this method is free from any resonance constraint and thus can be applied to any molecule. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Reports that energy gain is detected theoretically in a pulsed chemical laser amplifier based on a photon-branched chain reaction initiating in a gaseous disperse medium composed of H[sub 2]-F[sub 2]-O[sub 2]-He and Al particles by focused external infrared radiation. Laser-chemical kinetics of the laser amplifier.

Reports on the spectral optimization of a pulsed multiline HF chemical laser for efficient energy delivery through a low-loss fluoride glass optical fiber. Discussion on HF laser line selection methods; effect of carbon dioxide gas pressure on the total multiline output energy; Description of the process of energy delivery through the fluoride glass fiber.

Presents information on a study which investigated the characteristics of a high-pressure pulsed singlet oxygen generator for pulsed chemical lasers. Experimental procedure; Results and discussion; Conclusion.

Presents a numerical model for calculating the performance of a premixed pulsed supersonic hydrogen fluoride chemical laser. Integration of the laser kinetic equations and supersonic gas dynamics; Conditions for maximum gain and maximum laser energy for each of the input parameters; Information on the lasing zone length in the flow direction.

Present a study that theoretically investigated the output performance of a pulsed discharge initiated hydrogen/fluorine chain first vibrational overtone hydrogen fluoride chemical laser. Outline of a model to understand high efficiency overtone lasers; Results; Discussion.

Presents information on a study which investigated a novel computer model of a pulsed H[sub2]/SF[sub6] nonchain first vibrational overtone hydrofluorocarbon chemical laser to assess the overtone and fundamental laser performances. Demonstration of the first lasing of the vibrational overtone laser; Variation of the overtone laser energy with helium pressure; Description of the model.

Discusses the potential use of TII/Xe system as a continuous wave (cw), completely cyclic, self-contained atomic iodine laser. Pumping processes for the excited atomic iodine; Shortcomings of cw photolytically excited atomic iodine lasers; Factors that excited the TII dissociative levels in the rf discharge.

Presents a study which examined the quenching of NF singlet states in a hybrid chemical laser system. Experimental details; Results and discussion; Conclusion.

Focuses on four gain models for use in analyzing source-flow chemical laser resonators. Effect of using the gasdynamic calculation from the single-line model in a rotational nonequilibrium kinetics model; Details of an error introduced by decoupling the solution to the gasdynamic and laser kinetic equations; Impact of rotational nonequilibrium phenomena on lasing performance.

Presents a study that investigated the effects of fluorine donor additives and initiation level on hydrogen fluoride chemical lasers. Methodology; Analysis of the output characteristics of the laser; Measurement of the laser energy.

The laser emission spectrum of a flash initiated XeF2–D2 chemical laser indicated that translationally hot F atoms (31 kcal/mol) react with D2 to yield DF primarily in the v=2 state. Reaction of D+XeF2 was found to be too slow to contribute to the observed laser emission. [ABSTRACT FROM AUTHOR]

The rotational relaxation of HCl (v=1) by HCl is studied by infrared double resonance using two chemical lasers. State-to-state rate constants are derived from the measurements by comparison with a computer simulation based on two different scaling laws. The ECS theory based scaling law seems to provide a better fit to the experimental data than does the exponential gap law. With both scaling laws a correct description of the double resonance is obtained by including multiple rotational quantum transitions. [ABSTRACT FROM AUTHOR]

Features a study that analyzed the operational characteristics of the hydrogen-fluoride chain chemical lasers initiated by an intense electron beam in order to further improve the output performances. Optimization of the laser gas mixtures and the electron-beam-current density; Experimental results of the output characteristics; Comparison of theoretical and experimental results.

Presents a study that measured the delay time between the initiating pulse and the development of the laser emission pulse for various vibrational transitions in a supersonic Hartree-Fock chemical laser. Description of the apparatus; Analysis of the laser parameters; Results and discussion.

Presents information on a study which described the dependence of laser output power on the flow velocity at a cavity for a compact chemical oxygen-iodine laser. Description of chemical oxygen-iodine laser; Experimental apparatus; Results and discussion; Conclusions.

Develops a multikilojoule deuterium fluoride (DF) chemical lasers initiated by intense electron beams. Initiation modes of the DF lasers; Calculation of the initiation level; Means used to understand the temporal behavior of the DF laser pulse.

The process of laser beam homogenization in a gas medium placed in front of a thin metallic foil has been studied. Experiments were performed using the Prague Asterix Laser System iodine laser [Jungwirth et al., Phys. Plasmas 8, 2495 (2001)] working at 0.44 μm wavelength and irradiance of about 1015 W/cm2. Homogenization was detected both by directly analyzing the transmitted laser beam and by studying the shock breakout on the foil rear side. Results show that the gas ionization by the laser pulse induces a strong refraction and produces an effective smoothing of large-scale intensity nonuniformities. [ABSTRACT FROM AUTHOR]

A plasma source free from characteristic emission lines is described, based on laser irradiation of a water jet in a helium atmosphere. Various key aspects of the laser interaction are presented along with practical characterization of the observed isotropic ∼4–10 keV x-ray emissions, measurements of which indicate subpicosecond duration. Observations are consistent with a vacuum heating plasma mechanism at the helium-water interface and indicate strong potential for in-house ultrafast chemical structure dynamics application when coupled to contemporary detector developments. [ABSTRACT FROM AUTHOR]

We report on the applications of a single-longitudinal-mode (SLM) pulsed alexandrite laser system for diagnostics of parameters of flow/combustion interest. The laser system is characterized by its narrow linewidth, high peak power, and broad tunablity. The absolute frequency of the laser output was monitored by a wavelength diagnostic system, which included a high-resolution confocal etalon and a molecular iodine laser-induced fluorescence (LIF) detection system. Different nonlinear frequency conversion schemes were used to cover a large frequency range from the infrared to the deep UV. The versatility of the laser system for flow/combustion diagnostics is demonstrated in three applications, namely filtered Rayleigh scattering, high-resolution Doppler-free two-photon LIF of CO, and infrared LIF and polarization spectroscopy of CO2. The potential impacts of using this SLM laser system in laser flow/combustion diagnostic applications are discussed. [ABSTRACT FROM AUTHOR]

The high-power iodine laser system PALS (λ0=1.315 μm at the fundamental laser frequency, 1ω, and λ1/3=0.438 μm at the third harmonic frequency, 3ω), with a maximum laser intensity IL of up to about 3×1016 W/cm2, was used to generate highly charged Ta ions. Maximum ion charge states slightly above z=50+ were determined by using an electrostatic ion energy analyzer and the maximum energy of emitted ions, estimated from the ion collector signals, was even higher than Ei=22 MeV, as determined by track detectors. Charge-state distributions, as well as charge-energy distributions were evaluated for both 1ω and 3ω laser frequencies. The focus position with regard to the target surface (in addition to the focus spot size) determines not only the laser power density deposited and the amount of produced ions, but it also directly influences the mechanisms of ion generation. Highly charged ions with the charge states above 50+ can be generated either by using a sufficiently high laser intensity (about 1×1016 W/cm2) or, at lower laser intensities (IL>2×1014 W/cm2), in the case where the conditions for the relativistic self-focusing are met. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Discusses measurements of laser-imprinted perturbations and Rayleigh-Taylor growth with the Nike krypton fluoride laser. Extraordinary uniformity of the laser drive; X-ray framing diagnostic; Comparison of results with two-dimensional radiation hydrodynamics code that includes time-dependent induced spatial incoherence beam modulations.

Discusses the high-resolution x-ray imaging of planar foils irradiated by the Naval Research Laboratory Nike krypton fluoride laser. Backlighting of the thin plastic foils by a silicon plasma; Observation of instabilities that were seeded by linear ripple patterns on the irradiated sides of the thin plastic foils.

Presents a study that introduced a modified amplified spontaneous emission technique to measure the radial distributions of the optical gain and saturation energy density of a copper bromide laser. Details of the technique; Application of the technique; Experimental setup and procedure.

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.