State of and prospects for XeF(C−A) optically pumped lasers

Experimental and theoretical results are presented on an XeF(C?A) blue-green laser driven by 5-kJ energy. The laser was pumped by a ferrite-induced discharge of 90 cm in length. The output energy of 0.22 J was obtained with a plane-parallel resonator. A program to simulate laser operation has been developed. Numerical results for a wide range of conditions are compared with experiments performed by us and by other authors. It is found that intracavity refractive losses limit laser operation for XeF pressures above 3 torr. The laser efficiency strongly depends on the discharge-to-cavity length ratio. Possible ways to increase the laser power and efficiency are discussed.     

A thermodynamic description of the distribution of water in H2O-tributyl phosphate and H2O-tributyl phosphate-solvent systems

Various methods for describing the distribution of water in the H₂O-tributyl phosphate (TBP) system were considered. An equation for describing the deviations from the Henry law was proposed. A three-parameter equation for calculating the distribution of water in H₂O-TBP-solvent systems was derived. It is based on the additive solubility model and allows for the dependence of the activity coefficients on the TBP concentration. Based on the published data, the parameters of the equation for a number of systems were calculated.     

Spectral investigation of cw rf-pumped atomic Xe laser with a slab geometry

A radiofrequency excited atomic Xe slab laser with an active volume of 2 × 10 × 300 mm³ using a quartz envelope containing the laser-gas mixture shows a stable cw performance with an output power of almost 1 W. The free-running system oscillates, depending on gas composition and density, on several lines between 1.73 and 3.51 m. Line competition phenomena are observed. Single-line oscillation yields more than 500 mW.     

Study of the glow discharge in inert gases with water vapor

The behavior of the water vapor concentrations and fragments in wet plasma is studied. The results of plasma-chemical modeling are compared with the results of direct measurements of water molecule dissociation in plasma.     

Measurements of the atmospheric concentrations of nitrogen dioxide using the radiation absorption in a spectral range of 415 nm

The trace atmospheric concentrations of NO₂ are measured with the methods of the diode laser absorption spectroscopy and the phase shift of the modulated radiation. An electronic transition in a range of 415 nm is employed. For a measurement time of 20 ms, the sensitivity of the concentration measurements is about 10^?11 relative to the concentration of air particles (0.02 ppbv). At a time interval of 5–10 min, the reproducibility of the absolute concentration measurements (0.1 ppbv) is limited by the low-frequency fluctuations of the optical parameters of the spectrometer and the calibration system and corresponds to the level determined by the Allan variance.     

Extraction of nitric acid by tributyl phosphate solution in <Emphasis Type="Italic">n</Emphasis>-dodecane

Experimental data based on the extraction of nitric acid by 30, 12, and 5 vol % tributyl phosphate (TBP) solutions in n-dodecane were obtained and calculations of equilibrium were performed. It was shown that the values of the formation constants and hydrate numbers of mono-, di-, and half-solvates found for a system containing 100% TBP can be used in performing the calculations. It is also suggested that extraction of half-solvate proceeds with a lower constant of formation and a lower hydrate number when TBP is diluted by n-dodecane half-solvate.     

Orientational optical nonlinearity of nematic liquid crystals induced by high-molecular-mass azo-containing compounds

Processes of light-induced reorientation of nematic liquid-crystalline molecules induced by the addition of low concentrations (0.1–2.0 wt %) of comb-shaped polymers and carbosilane dendrimers containing azobenzene fragments are studied. When the molecular structure of the above compounds becomes more complicated, the induced orientational nonlinearity increases. The introduction of 2G and 3G dendrimers into a nematic has for the first time made it possible to visualize and study a purely optical first-order Freedericksz transition in the field of a linearly polarized wave.     

Theoretical and experimental investigation of a waveguide CO2 laser with radio-frequency excitation

A comprehensive experimental and theoretical study of the optimization of a continuous-wave radiofrequency (rf) excited CO₂ waveguide laser is presented. The numerical simulation includes the modelling of the gas-discharge plasma parameters like the plasma impedance and energy deposition, the laser kinetics and finally the influence of the resonator feedback on the lasing process. Along with this theoretical study, an extensive experimental research program enabled us to optimize the laser performance of the CO₂ waveguide laser. As a result, a total output power of 42 W and a specific output power of 1.1 W/cm were obtained.     

Dynamics of a radiating surface discharge

We have elaborated a code for numerical treatment of two-dimensional problems of the dynamics of a surface discharge with inclusion of radiative energy transfer. The gas dynamic, electric, and radiative properties of a surface discharge in atmospheric air have been studied experimentally for a total energy input of 100 J/cm in the input power range 3–6 MW/cm. A new technique involving a discharge sliding along a conducting surface is applied to initiate an extended surface discharge. The calculations agree satisfactorily with the experiments. The method elaborated here makes it possible to calculate a broad class of linear discharges with an eye to produce a radiation source with problem-oriented spectral power characteristics.