V. Gorelov, I. Gostev, V. Kalinovsky, I. Komissarov, V. Konovalov, I. Konovalov, V. Mikhalkin, V. Nikolaev, I. Sevryugin, A. Smirnov, R. Sobolev, L. Shornikov, S. Velikanov
The paper reports on a study of oxygen-iodine laser operating on active mixture formed by electric discharge in pulseperiodic
mode. Experiments were performed with a laser cavity 5 m long. Laser pulses obtained for three various
chlorine flow rates ((62 ± 2) mmol/s, (92 ± 2) mmol/s, (105 ± 2) mmol/s) have been manipulated by the statistic rules.
The repetition rate of pulses was 12.5 Hz. The chlorine concentration in the laser cavity was varied in the experiments
from 1.0·1015 to 1.0·1016 cm-3.
The research activities in creation of atmospheric pressure laser with the output of ~ 33 W, pulse repetition rate up to
2200 Hz, efficiency of ~ 1.6% (DF-laser) and the output of ~ 40 W, pulse repetition rate up to 2000 Hz, efficiency of ~
2% (HF-laser)
S. Velikanov, V. Gorelov, I. Gostev, Ye. V. Ireshev, V. Kalinovsky, I. Komissarov, V. Konovalov, I. Konovalov, V. Mikhalkin, V. Nikolaev, I. Sevryugin, A. Smirnov, R. Sobolev, L. Shornikov
The paper describes a study of pulse-periodic operation of a chemical oxygen-iodine laser. The generator in use was of the jet type with high chlorine utilization degree (⩾97%). Atomic iodine was released by dissociating methyl-iodide (CH3I) in volumetric electric discharge. Steady lasing was achieved at a repetition rate up to 30 Hz.
The emission energy attained per individual pulse in a train was 1.1 J at a pulse energy repeatability of (3÷5) % and a specific energy extraction from the active medium of 1.7 J/L. The lasing pulse duration depended on the concentration of methyl-iodide and the energy deposited into discharge. The minimal half-height duration of pulses was achieved as 10 &mgr;m at a concentration of atomic iodine in the laser cavity ~1*1015 cm-3.
The feature for DF laser ecology applications in its ramified spectrum. The DF laser energy distribution in selective and non-selective modes is investigated. The non-selective and selective outputs were 42.7 and 128 (totally) mJ accordingly.
The paper performs experimental issues from development and optimization of the selective cavity configuration in the electric-discharge DF laser for the lidar intended to monitor air methane. Using the selective resonator principle was shown to provide optimal feedback simultaneously at two selected wavelengths and allow us to form probing pulses consisting of in-time sequence of on- and off-lines. It was demonstrated experimentally that application of such a probing pulse would make it possible to build a simple and positivei-operation emitter-pickup system for lidar, provide the least mass/dimension values and consumed energy, and to enhance to operation safety of the entire complex.
The paper concerns with calculative and experimental development of a remote electric-discharge DF-laser analyzer for subterranean methane monitoring up to its explosive concentrations. The analyzer is built using a lidar scheme when the probing emission is reflected by artificial or natural object located in a subterranean measurement path. Methane records in the air are made using the differential absorption technique. The required metrological parameters of the analyzer are reached with the multi-frequency laser atmospheric control. A block diagram of the methane analyzer is given together with procedures to probe mine media with many frequencies in the spectral range from 3.6 to 3.8 μm. The lidar model was tested under conditions simulating physical values of the subterranean air: (1) methane air content -- up to 3% vol.; (2) dust content -- about 10 mg/m3; (3) probing path length -- about 50 m.
The paper concerns with calculative and experimental development of a remote electric-discharge DF-laser analyzer for subterranean methane monitoring up to its explosive concentrations. The analyzer is built according to lidar scheme when the probing emission is reflected by artificial or natural objects located on a subterranean measurement path. Methane records in the air are made using the differential absorption technique. The required metrological parameters of the analyzer are reached with the multi- frequency laser atmospheric control. The experimental factors of methane absorption in a spectral range from 3.6 to 3.8 micrometers and DF laser energy performance per line in a spectral range from 3.5 to 4.0 micrometers generated with a tunable selective resonator are performed. An excess of a factor 2 to 30 per the per line probing energy of the lidar operating with selective resonator over that with non- selective one is demonstrated. The probing energy of the lidar operating with selective resonator over that with non- selective one is demonstrated. The performed theoretical calculations determine the required power of providing radiation, optical on/off - line combinations of the laser, and measurement accuracy attained on measurement paths from 10 to 100 m long with the allowance for measurement- interfering factors under the conditions of detection of diffusively reflected lidar return form artificial and natural objects. A block diagram of the methane analyzer is given and procedures for multi-frequency probing of the mine medium are performed for a spectral range from 3.6 to 3.8 micrometers .
An applicability analysis of a DF laser in atmospheric remote control of SO2 is performed: experimental absorption factors of SO2 are given at various emission lines of a DF laser; possible errors from the spectral reflectance dependency for topographic objects are considered and the method of their correction is offered.
The study of DF laser generating average power 25 to 30 W at 1,200 Hz repetition rate is reported. Acoustic perturbation effect on the stability and homogeneity of discharges produced in the laser active medium and thus on output laser power is demonstrated.
KEYWORDS: Optical amplifiers, Amplifiers, Light sources, Energy efficiency, Chemical lasers, Chemical reactions, Explosives, High power lasers, Near field, Mirrors
A study was made of a laser based on a chain reaction of fluorine with hydrogen (deuterium) initiated by powerful light sources and operating in the amplifier mode. The conditions for reaching a near 100% energy efficiency of the amplifier at an active mixture length up to approximately 6 meters were determined experimentally. Spectral characteristics of the laser radiation were investigated thoroughly. The tolerable extent of difference between the actuation time of the master generator and amplifier was determined. A possibility was demonstrated to attain a low radiation divergence.
Chemical reactions are abundant sources of energy varieties concentrated in their excited products. This experimental fact constitutes the basis of the conception stated by Poolany J. C. in 1961, who offered to use exothermic chemical reactions for population inversion. This conception was implemented by Russian scientists A. N. Oraevsky and V. L. Tal'roze in their works. It was they who formulated the major requirements which chemical reactions must meet for effective lasing.
The DF laser's capabilities for monitoring natural gas and petroleum products in pipeline areas are considered. The absorption coefficients of methane, ethane, and propane were determine experimentally for 11 spectral lines in the 3.55- 3.75 micrometers range of the DF laser output. The criteria were formulated for selecting analytic and reference lines suitable for measuring atmospheric hydrocarbons by means of the differential absorption technique. Combinations of analytic and reference lines were chosen according to these criteria. The laboratory mock-up of hydrocarbon analyzer implemented around a DF laser was tested.
Performance has been investigated of a broadband chemical laser utilizing chain and nonchain reactions and emitting simultaneously from excited HF* and DF* molecules. Simultaneous stimulated emission of radiation in the spectral ranges of 2.7 - 3.0 micrometer and 3.7 - 4.1 micrometer has been obtained. Theoretical dependencies are presented of laser energy characteristics on the ratio of initial H2 and D2 concentrations in a working mixture.
The characteristics of 45 liters active volume chemical laser, which chain reaction was initiated by two contrary electron beams with 1 Hz repetition rate, have been investigated. Maximum single pulse energy was about 5 KJ, radiation divergence -- near 10-4 rad.
KEYWORDS: Fluorine, Chemical lasers, Hydrogen fluoride lasers, Hydrogen, Chemical reactions, Contamination, Control systems, Energy efficiency, Laser development, Laser optics
A brief review of the investigation results of chemical lasers based on the chain and nonchain reaction of fluorine with hydrogen (deuterium) made in the Russian Federal Nuclear Center (VNIIEF) is presented in this report.
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