Numerous investigations testify that technological methods of friction part surface modification are effective means of fight against wear. Wild dissemination of technological lasers for given property surface layer formation is kept back because of potential possibilities of different materials laser treatment are completely not unveiled yet. The conditions of laser radiation interaction with structural steel used for making of high-loaded rolling-contact bearings worked under conditions where cyclic contact loads are in action have been investigated by us. The regularity of physical mechanical properties and microstructure variations in laser affected zone have been revealed and the main characteristics effected on resistibility of surface layers to flaking and wear have been determined. The optimum characteristics of laser treatment process have been established. The influence of laser track disposition on operating surface on service properties has been studied. The recommendations for application of investigation results for increasing in carrying capacity of high-loaded rolling-contact bearing have been elaborated.

Numerical modeling of gas, pulsed, UV preionized Transversely Excited Atmospheric (TEA) carbon-dioxide laser has been considered. The modeling is carried out for case of a specific electrical circuit of TEA CO2 system operating with CO2/N2/He and CO2/N2/H2 gas mixture. Proposed model represents the time evolution of voltage, current and electron concentration on a satisfied manner in inter-electrode laser space. Agreement between theory and experiment is quite good. Simulated values of voltage and current are of short duration which in a manner affects the optical, i.e. laser pulse.

Humanity can struggle with the dangerous cosmic objects in our time and its parameters knowledges are needed. A present paper deals with prospects for the cosmic IR lasers using for remote sensing measurement of the various cosmic objects parameters: dimensions are more then 100 m, velocity is more then 30 km/s. A laser under solar energy pumping was elaborated. The more effective laser parameters were defined for the smaller bodies velocity analysis. The laser is supplied with an automatic tuning optical system. Possibilities are estimated for diagnostic measurements with using modulated laser radiation. The C02 or solid states lidars are needed for the asteroids detection’s at a distances of 30 000 km to 10 Mkm from an earth surface. A laser Doppler anemometer method with adaptive selection is used. The peak transmitted optical power depends on photoreceiver parameters and other system components. The high sensitivity ( 500 V/W ) photoreceivers without a cooling are elaborated today. A constant lasers exit power is upper 100 kW, at present. Therefore, a such diagnostic task can be solved by the measuring system with a high power laser and the new photoreceivers.

Generators with inductive energy storage units and semiconductor opening switches designed for laser excitation are described. Operation of the generators on gas-discharge load is considered and possible excitation modes are discussed. Longitudinal N2-laser with inductive energy storage unit and semiconductor opening switch is investigated. It is shown that pumping by inductive energy storage unit reduced the influence of the discharge circuit inductance and broadened the range of the operating pressures at which lasing was possible. Besides the laser output energy may be increased by means of peaking capacitors connected in parallel with a discharge tube. Transverse discharge non-chain HF-laser and C02-laser are developed basing on this pumping technique. Output energy of 0,6 J and 3,2 J and the laser efficiency of 5,5% and over 17% were demonstrated on H2-SF6 and He-CO2-N2 gas mixtures, respectively. High laser parameters obtained demonstrate considerable promise of such inductive generators for pumping different gas lasers.

Spatially resolved gain distributions of RF excited slab CO2 laser medium are measured in four lines of P branch (such as P(14),P(20),P(26),P(30)) to examine the difference between the center of slab electrodes spacing (alpha discharge region) and near the electrode region (sheath). For measurement low7 power C02 laser beam is put through the spacing of the slab electrodes and passed beam is detected as a cross-sectional image by pyro-electric detector arrays each of which has a resolution of 0.1*0.1mm. The result of P(20) line was 0.4%/cm at the center and down to half near the electrode. And from measured four lines of gain gas temperature (CO2 rotational temperature) is calculated to be 400K at the center and increasing to about 550K near the electrode assuming distribution of rotational levels of each line is accord to a Botzmann distribution. And by solving the heat transfer equation using obtained temperature distribution, heat generation is found to be occurred near the electrode.

Output characteristics of a pulsed e-beam controlled discharge laser operating on the first-overtone (FO) transitions (?V=2) of CO molecule have been studied both experimentally and theoretically. Various sets of dielectric mirrors with high reflectivity in the range of the overtone spectrum have been used for the laser resonator. Multiwavelength lasing has been obtained in the wide spectral range of 2.5 - 4.1 µm on vibrational transitions from 6?4 up to 37?35. Maximum output efficiency as high as 11% has been experimentally obtained for the broad band FO CO laser. Output efficiency of the laser operating on a few vibrational bands within the relatively narrow spectral range 2.5-2.7 µm comes up to 5% at entirely suppressed fundamental band (?V=1) lasing. FO CO lasing was observed within an initial gas temperature interval of 100-220 K. Spectral characteristics of the overtone laser operating on a selected set of vibrational bands have been analyzed theoretically. Theoretical calculations based on the experimental data predict that multiline FO CO laser efficiency can be increased up to 20%.

In this paper, the theoretical studies, considering the formation of boundary layer, have been performed to describe RF discharges in annular CO2 lasers with diffusion-cooling. Such characteristic parameters as spatial distributions of electron density, electric field, RF power density and discharge mixture temperature have been evaluated, which can be used to explain some experimental properties of RF discharges very well.

Iodine molecule was dissociated prior to injection in supersonic Chemical Oxygen-Iodine Laser (COIL). In some cases, output power enhancement was observed. However, the output power was decreased at the optimum titration (iodine/oxygen ratio). A quasi-two dimensional simulation was employed to analyze the effect ofiodine pre-dissociation. It was revealed that the high iodine atom concentration at the plenum is responsible for the power reduction. The method to improve the output power by pre-dissociation is discussed.

Unstable resonator with a stable core was developed for Chemical Oxygen-Iodine Laser (COIL). An optical resonator simulation code was developed to optimize the design parameter of the resonator. “Partially coherent optical field” model was employed to handle with multiple transverse mode oscillation. The resonator was successfully oscillated, and a 14 W output with M2=29 was obtained. Theoretically calculated laser output, near-field pattern, and beam quality was in good agreement with experimental results.

A two-dimensional program is applied to simulate the chemical dynamic process,gas dynamic process and lasing process of a combustion-driven CW HF overtone chemical lasers.Some important parameters in the cavity are obtained.The calculated results include averaged pressure and temperature,zero power gain coefficient, laser spectrum, output power, chemical efficiency and overtone efficiency.Based on the numerical simulation,the influence of entering gas flow parameter,nozzle structure and nozzle array length on the performance of HF overtone lasers are investigated separately.Because of small zero power gain coefficient of each HF overtone spectral line,the saturation degree of gain medium in the cavity is the most important parameter to influence the overtone efficiency of HF lasers.

The axial flow COIL is a convenient device to study the gain and storage energy life-length along the gas flow. When the velocity of the axial flow close to the sonic velocity and the active medium is preliminary cooled the conditions like in the supersonic transverse flow COIL can be realized. The presented axial flow COIL was driven by jet type SOG. The next gas flow rates were used in all experiments: 20 mmole/s of the primary buffer gas, 10 mmole/s of secondary buffer gas and 10 mmole/s of chlorine through the jet SOG. The maximum output power 106 wt was obtained at ~0.05 mmole/s of the iodine flow rate with primary and secondary nitrogen buffer gas. The cooling of the primary nitrogen to 80°K resulted in 130 wt output power. The using helium at 80°K instead of nitrogen resulted in 186 wt output power or 20.5% total chemical efficiency for 0.1 mmole/s of the iodine flow rate. The exposition of the laser beam at the black wood target showed that the main part of laser power was inside the circle 22 mm in diameter.

Since COIL was invented, an interest exists to produce singlet oxygen using techniques without dangerous chemicals. One possible solution is to employ a discharge in pure oxygen or in oxygen mixtures. Up to date, no discharge system has produced enough singlet oxygen to operate a laser, as it is necessary to provide a very high energy load in the discharge —up to 100 kJ/mol. However, several recent papers claim up to 15-20% of singlet oxygen yield. Glow discharge in a vortex flow is known to be extremely stable at high pressures and currents and, therefore, permits very high power load. Pure oxygen was exited in a vortex tube of 1 .5 cm diameter at the pressures of 2—15 ton in the DC glow discharge with the gap between electrodes of 1—8 cm. Exited oxygen concentrations of several percents in afterglow of a1? and b1? states were measured detecting emission at 1 .27 and 0.762 microns. Current density up to 1 .5 A/cm2 was achieved, that is more than order of magnitude larger that typical values for stationary discharge. The dependencies of exited molecules concentration on current, pressure for a number of different discharge geometry are represented.

So far the impressive successes are obtained in development of continuous-wave chemical oxygen-iodine lasers (COIL). But some applications require the laser operating in a pulse mode and generating the power as high as possible. It is known the COIL with volume instantaneous generation of atomic iodine generates the pulses which power is several orders of magnitude higher that of CW mode at the same flow rate of chemicals. More increase of output power can be obtained by using Q-modulation. For efficient extraction of stored energy the frequency of modulation should be as high as reciprocal time of inversion population recover. i. e. megahertz scale. Such a high modulation frequency can be produced with electrooptic or acousto-optic modulator (AOM). The experimental results of application of AOM to pulsed COIL with a discharge pulsed generation of atomic iodine are presented. The AOM power supply allows one to vary the temporal parameters of modulation. The laser generates a train of pulses with the given duration and repetition rate. Experiments show that optimization oftemporal parameters of modulation is required

This paper deals with an estimation of the Einstein A-coefficient for spontaneous emission of singlet delta oxygen, 02(1?g), fld contributes to a current discussion that was launched recently about the conventionally used value of 2.58 x 10-4 s-1 by Badger et al.1 (a half-lifetime of O2(1?g) corresponding to 45 min).The A-value is used in a Chemical Oxygen- Iodine Laser (COIL) for an evaluation of O2(1?g) concentration determined from its fundamental emission. The published values of the A-coefficient substantially differ, corresponding to a radiative lifetime of O2(1?g), ??rad from ~53 min to ~151 min. This fact can make questionable an evaluation of COIL performance. In this paper, the Einstein A-coefficient was computed from the comparison of O2(1?g) concentrations obtained by two independent experimental methods - the electron paramagnetic resonance (EPR), and the emission spectroscopy at which a proposed mathematical model for calculation of O2(1?g) concentration was used. Singlet oxygen was generated chemically by the reaction used in a COIL, in contrast to other papers concerned in this fundamental phenomena. A great effort in our work was devoted to the EPR spectra evaluation as it was shown that it affects crucially the resulting value of the A-coefficient. The average value of the Einstein A-coefficient following from our investigation is equal to (2.24 ± 0.40) x 10-4 s-1 that corresponds to ??rad of~ 74 min (a half-lifetime of 51 min)

Various essential parameters like mass transfer coeff, volumetric flow rates etc. for a typical KW level COIL have been considered and the gas residence time and thus the size of the SOG has been estimated. The SOG based on this design has been fabricated and is under evaluation. The design of SOG and various other subsystems like nozzles, resonator and liquid nitrogen trap have been discussed in this paper. Further systematic studies have been carried out on the shelf life of basic hydrogen peroxide (BHP) in the temperature range of -10°C to +10°C using titration technique. Studies indicate that the solution prepared at -10°C to -15°C and stored at this temperature, the decomposition starts only after 36-42 hours. However, at higher storage temperatures, the decomposition is faster.

There is currently no existing or programmed system with a capability to negate unguided rockets and mortar / artillery projectiles after they are launched. There is limited capability to negate UAVs that need to be countered at a sufficient range to preclude detection, identification, and targeting of friendly forces. With the threat moving toward the proliferation of low cost unmanned threat platforms and munitions, there is a need to develop and field cost effective solutions for this ADA mission. The THEL system concept is an application of High Energy Lasers that is a potential weapon system of the future to provide this required force protection.

This paper describes the results achieved in the development of a chemical oxygen iodine laser (COIL) for industrial applications. The COIL was designed to obtain kW class output power with jet type singlet oxygen generator (SOG). The output power with subsonic flow was 230 W at 15 mmole/sec chlorine flow rate. The real-time holographic interferometer with a digital high-speed camera was applied to the visualization of mixed gas flow in COIL. The visualization of gas flow shows the profile of the variation of refractive index and can be applied to the measurement of the variations in the pressure and the temperature of the gas.

Hyperfine level relaxation of I2P1/2 by O2(X), 12P1/2(P=2) + 02(X) I ^^=3) + 02(X) and electronic quenching of I 2P ./2 by 02(X) were investigated over the temperature range 10 - 295 K. The hyperfine transfer rate constants were found to be insensitive to temperature over this range. At room temperature the rate constants for hyperfine transfer and quenching were comparable, but the latter decreased with decreasing temperature. The energy transfer rate constants obtained in this study were smaller than estimates currently used in computational models of chemical oxygen iodine lasers. The measurement technique reported here relies on the fact that photolysis of I2 via the #3n(0u+) state produces 12P1/2 atoms with non-statistical population of the hyperfine sub-levels. The photolysis wavelength and temperature dependence of the product state distribution was investigated. The results suggest that avoided crossings between the potential energy curves of I2 at large intemuclear distances are responsible for the anomalous hyperfine sub-level population distributions. Key words: Energy transfer, hyperfine level relaxation, chemical oxygen iodine laser, COIL, photodissociation dynamics.

Simulation of chemical lasers such as the chemical oxygen-iodine laser (COIL) laser is of timely interest due to ongoing commercial and military development programs. Accurate models of the gas dynamics and chemistry within a COIL have been developed using Computational Fluid Dynamics (CFD) codes, matching data from experiments designed to probe these physics. This work details the use of these codes to investigate the supersonic injection of molecular I2 and atomic I into the supersonic region of the O2(1?) flow in the COIL, and compare these results with a simulation of sonic injection of I2 into the subsonic region of the O2(1?) flow. The performance of each of these injection mechanisms is characterized by the theoretical power extracted from a Fabry-Perot resonator model, which then serves as the primary basis for comparison. Additional quantities such as power available and chemical efficiency are used to compare and contrast the performance of each concept. Based on these comparisons, the supersonic-supersonic injection methods demonstrate a performance increase over the traditional subsonic methods, with supersonic injection of I atoms providing the greatest performance increase.

A direct measurement of gain on the electronic I (2P3/2) - I*(2Pi/2) transition of atomic iodine at 1.315 jam using tunable diode laser is demonstrated. The population inversion results from the efficient energy transfer between NCI (alA) metastables and I (2P3/2) atoms. Ground state iodine atoms and NCI (a1 A) metastables are produced in a transverse subsonic flow device from the stepwise reaction of Cl atoms with HI followed by the reaction of Cl with azide (N3) radicals, respectively. Under current experimental conditions, a gain of 0.020%/cm is obtained and appears to be limited by reagent number density. A kinetic model was constructed to simulate the experimental gain profile using a mechanism consisting of fully coupled finite rate chemistry and 1-D fluid dynamics. Good agreement with experimental and theoretical calculations are obtained. Keywords: Gain, population inversion, atomic iodine, NCI (a*A) metastables, azides, energy transfer

We present results for collisional broadening for selected absorption lines in water vapor and atomic iodine relative to diode laser- based diagnostics for chemical oxygen iodine lasers. For water vapor we measured broadening of the 1.3925 µm line by numerous gases including oxygen, water vapor, nitrogen, and helium. Preliminary measurements were also completed on the (3,4) hyperfine line in atomic iodine at 1.3152 µm.

The interaction of a Transversely Excited Atmospheric (TEA) CO2 laser, pulse duration less than 2 µs, with low thickness coatings of titanium-nitride (TiN) and titanium-aluminum-nitride (TiAl)N, deposited on steel-substrate is considered. The investigations have shown that both coatings had been intensively modified by TEA CO2 laser beam. The (Ti,Al)N compared to TiN shows more expressed changes in the bombarded area: cracking and other surface modifications. Intensive surface exfoliation was observed only for (Ti,Al)N. Especially attention was devoted to the effects of laser pulse shape on morphology features. Generally, laser pulses with tail induced more signified changes on the coating surface.

A new approach to space debris removal by laser is suggested using a repetitively pulsed high average power chemical oxygen iodine laser (COIL). The pulsed mode of operation which is achieved by magnetic gain switching of a CW device considerably enhances the peak-to-CW power of the laser leading to an efficient debris clearing performance as compared to previous approaches. In particular, the chemical oxygen iodine laser promises to be rather compact and to substantially reduce the total debris clearing time. The current maturity of COIL technology greatly supports the present approach.