Chris E. Little

Influence of remanent electron density on the performance of copper HyBrID lasers

Abstract Evidence is presented for the strong removal of free electrons in the interpulse period of copper HyBrID lasers when HBr is added. Electron attachment and accelerated recombination processes lead to a relatively low free electron density at the end of each interpulse period. The influence of the low number of remanent electrons on various discharge characteristics is held to be ultimately responsible for the higher efficiencies, larger specific average output powers and superior beam characteristics of that type of laser compared with conventional copper lasers.

Characteristics of pulsed discharges in copper bromide and copper HyBrID lasers

Comparative measurements of discharge electrical waveforms have been carried out with a Ne-H/sub 2/-CuBr laser, a Ne-CuBr laser, and a Cu HyBrID laser, each of the same size and geometry, and under the same conditions of excitation. From the general similarity of the electrical characteristics of the HyBrID laser and the Ne-H/sub 2/-CuBr laser, together with a reappraisal of the role of hydrogen, it is concluded that the main characteristics of these lasers (high efficiency, high average output power, and special features of their excitation pulse waveforms) can all be qualitatively explained if we assume that HBr and not hydrogen (molecular, atomic, or ionic) is the responsible agent which acts via the process of dissociative attachment of electrons to HBr during the interpulse period and during the early stages of the discharge current pulse.

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 copper HyBrID laser of 120 W average output power and 2.2% efficiency

A copper HyBrID laser (λ=510.6, 578.2 nm) is reported which produced 121 W at 2.2% efficiency (based on stored energy), with a pulse recurrence frequency of 18 kHz. For an output power of 100 W, the efficiency was 2.6%. A 21% enhancement in output power was achieved by eliminating parasitic stimulated emission due to back-reflection from the silica discharge-tube windows.

A high-power high-efficiency Cu-Ne-HBr (λ = 510.6, 578.2 nm) laser

Abstract A high-power copper bromide laser, which utilizes the technique of in situ production of CuBr by reaction of copper of HBr, is reported. The 45 mm bore copper HyBrID (Hydrogen Bromide In Discharge) laser has produced a maximum average output power at 510.6 and 578.2 nm of 94W at 21 kHz pulse recurrence frequency, with an efficiency (based on stored energy) of 1.5%. The corresponding specific output power was 52 mW cm-3. An efficiency of an average output power of 40 W. Laser oscillation can be obtained less than 15 minutes after a cold start-up, with full power attained 5 min later.

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. >

A copper HyBrID laser with 2 W/cm/sup 3/ specific average output power

A copper HyBrID laser (/spl lambda/510.6, 578.2 nm) is reported, which produced an average output power of 9.5 W from an active volume of just 4.77 cm/sup 3/. These figures correspond to a record specific average output power for copper lasers of any type of 2.0 W/cm/sup 3/. >

Radial and temporal laser pulse profiles in a 0.2-kW average power copper HyBrID laser

The transverse profiles and evolution of the laser intensities of a high-power copper HyBrID laser (510.6 nm, 578.2 nm) are presented. Both the radial profiles and temporal evolutions of the laser pulse intensities are markedly different in a large- bore (6 cm) HyBrID laser than in conventional elemental metal copper vapor lasers of similar dimensions. The differences in laser intensity distributions and their temporal evolution are attributed to the electron-attaching properties of hydrogen and bromine in the laser buffer gas mixture of a HyBrID laser. The significantly low conductivity of the gas in a HyBrID laser means that the plasma skin effect is relatively weak and does not influence the development of laser oscillation to any great extent; oscillation in a 6 cm bore HyBrID laser begins on the tube axis first and at the wall 3-4 ns later; the time-averaged laser intensity peaks on the tube axis.

1.3 W average power at 255 nm by second harmonic generation in BBO pumped by a copper HyBrID laser

We present the first report of SHG using a copper HyBrID laser. These results allow us to discuss the main factors that determine SHG of HyBrID laser output radiation in a BBO crystal.