Dimo N. Astadjov

Parametric study of the CuBr laser with hydrogen additives

A systematic investigation of the electric parameters of the CuBr laser plasma during the excitation pulse in their correlation to the laser output characteristics is presented. Based on the electric parameters, the temporal course is calculated of the electron density during the discharge. The authors offer a simple mechanism which generally explains how the hydrogen occurred in the copper vapor laser. The mechanism consists of shielding copper ionization by the process of electron detachment from negative hydrogen ions. >

Effect of hydrogen on CuBr laser power and efficiency

Abstract Addition of small amounts of hydrogen to the neon buffer gas in a CuBr laser causes doubling of the average output power and laser efficiency. An efficiency of 1% is easily obtained. Electrical parameters of the pulsed discharge as functions of the hydrogen additive pressure are reported.

Copper bromide laser of 120-W average output power

A Ne-H/sub 2/-CuBr laser (/spl lambda/510.6, 578.2 nm) is reported, which produced an average output power of 120 W at 2.5% efficiency (based on stored energy) and 100 W at 3% efficiency. These output power and efficiency figures are record values for copper bromide lasers. The sealed-off device produced maximum output power at a pulse recurrency frequency (PRF) of 17.5 kHz. Laser operating characteristics and electrical parameters are described.

A new circuit for CuBr laser excitation

A novel electrical circuit for CuBr laser excitation which consists of two interacting capacitive circuits is reported for the first time. An output power of 19 W with an efficiency of 1.6% was obtained. Some features of the laser operation, such as the voltage of the electrodes, the current pulse and the laser pulse, are given.

Temporal and radial evolution of the populations of CuI levels in the CuBr vapor laser

Populations of CuI ground state, resonance, and metastable levels have been measured in CuBr laser with and without hydrogen additives. Temporal evolution and spatial distribution populations have been studied during the excitation pulse and also during the interpulse period of time. Addition of hydrogen results in a smaller rate of resonance and metastable levels excitation and smaller depopulation of the ground state during the excitation pulse. Repopulation of the ground state after the excitation pulse with hydrogen is much faster. CuBr molecules have been detected only in the periphery of the active zone. The density of the CuBr molecules had no noticeable change either during the excitation pulse or in the interpulse period. >

Influence on operating characteristics of scaling sealed-off CuBr lasers in active length

Abstract We have scaled sealed-off copper bromide lasers in average output power from 24 W to 58 W by increasing the active length from 50 to 120 cm. It was found that the increase in active length was accompanied by an increase in operating efficiency from 1.8 to 2.2%, and a reduction in power dissipated at the electrodes. A complex behaviour of laser output power on pulse recurrence frequency has been attributed to the influence of acoustic resonances on particle densities in the laser discharge. It was also found that the CuBr reservoir temperature must be increased as PRF is increased in order to maximize output power. The hydrogen partial pressure optimum for laser oscillation in our 40 mm discharge tubes was found to be twice that found in earlier studies in which the gas discharge was limited to 20 mm effective diameter.

A CuBr laser with 1.4 W/cm/sup 3/ average output power

An average laser power of 6.7 W has been obtained from a small-bore CuBr laser with a constructive active volume of 4.77 cm/sup 3/, i.e., a record specific average power of 1.4 W/cm/sup 3/ for multikilohertz operation of copper vapor lasers has been achieved. It was found that the small-bore CuBr laser can operate with a neon buffer at atmospheric pressures. >

Long-lived sealed-off CuBr laser

Abstract Investigations on the life-time of a whole-heated sealed-off CuBr laser are reported. Keeping the bromine concentration low enough not less than 500 h of laser operation is already realizable. The decrease of laser power is due mainly to output windows pollution.

High-brightness CuBr MOPA laser with diffraction-limited throughout-pulse emission

CuBr master oscillator-power amplifier (MOPA) laser system fitted with a generalized diffraction filtered resonator (GDFR) is reported to produce high-quality beam of throughout-pulse diffraction-limited laser emission at the repetition rate of /spl sim/19 kHz. The comparison with typical (stable and unstable) resonator configurations for CuBr lasers has featured out its high brightness accompanied by a very low beam divergence permanent within laser pulse. This intrinsic characteristic of GDFR-MOPA laser radiation makes it a perfect light source for fine laser applications.

Energy dissipation in the electrodes of CuBr laser-like discharges

Energy dissipation in the electrodes of CuBr laser pulsed discharges has been studied in a gaseous environment relevant to a copper vapour laser and with discharge length scaling. The power lost in the electrodes significantly increases not only with a decrease in electrode separation but also more compounds are added to the medium. The total energy losses in both electrodes range from to of the storage capacitor energy. This contributes much to the low efficiency of a copper vapour laser. The result cannot be explained by a simple redistribution of electrical power between the discharge plasma and the electrodes proportionally to their impedance - pre-electrode processes must also be considered.