Konstantin I. Zemskov

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.

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.

Mechanism of pulsed inversion in a process of ion-ion recombination

Pulsed ion-ion recombination lasers can have high output power and efficiency if it will be possible to realize idealized mechanism of inversion suggested in our previous publications. How close it will be possible to come to realization of the idealized scheme depends on the proper choice of the active medium components (metal, buffer gas, electronegative molecule} as well as corresponding conditions of excitation and recombination. Some possible pairs of positive and negative ions of several metals with negative ions of Br, Cl, and I are discussed.

Possible systems for realization of an ion-ion recombination laser: recombination with negative ion of oxygen

Possible pairs of positive metal ions and negative ion of oxygen suitable for realization of efficient ion-ion recombination are considered. Predominantly populated by ion-ion recombination levels of several metal atoms are indicated. Possibility of population inversion creation and lasing on some transitions in metal atoms as well as development of efficient non-coherent radiation sources is discussed. Energy level diagrams illustrating positions of ii-resonances and transitions from the predominantly populated by ion-ion recombination levels are presented for 9 metal atoms.

Initial stage of discharge and its influence on characteristics of copper vapor lasers

The main processes during initial stage of pulsed discharge in copper vapor lasers including the operation of a cathode and discharge development in cold end zones of a discharge tube are considered. The importance of fast voltage rise, proper operation of the cathode and recombination processes in the cold zones is emphasized.

Brightness Amplifiers In Optical Systems

Brief review of the last results on laser brightness amplifiers for different optical systems is given. Nonlinear properties of these systems and some new effects connected with the saturation of active medium of amplifiers are discussed. Some possible applica-tions (processing of microobjects, projection on large screen, TV-projection ...) are described.

Gold vapour brightness amplifier

Abstract The main characteristics of a gold vapour brightness amplifier at 627.8 nm have been measured in the scheme of a projection microscope. Maximum effective amplification about 3500 per single pass of active element has been achieved. The maximum light power on the projection screen was more than 0.5 W. The measurements have shown that a gold vapour amplifier can be used as an brightness amplifier in a practical projection microscope.

Stimulated low-frequency Raman scattering in aqueous suspension of nanoparticles

The low-frequency acoustic mode in nanoparticles of different nature in aqueous suspension has been studied by stimulated low-frequency Raman scattering (SLFRS). Nanoparticles investigated (CuO, Ag, Au, ZnS) had different dimensions and different vibrational properties. Synthesis of cupric oxide nanoparticles in acoustoplasma discharge is described in details. SLFRS has been excited by nanosecond pulses of ruby laser. Spectra of the scattered light had been registered with the help of Fabry-Perot interferometer. SLFRS conversion efficiency, threshold and frequency shift of the scattered light are measured.

Anti-Stokes luminescence in nanoscale systems

Luminescence of nanomaterials in green-blue range, anti-Stokes with respect to the exciting ruby laser pulses, is studied at different temperatures. Both high-ordered systems and random materials have been used as samples. Spectral and temporal characteristics of the luminescence have been measured. Two types of temporal behavior have been found out depend on temperature. Long luminescence (up to few seconds) under nanosecond excitation has been shown to exist only at the temperatures below the definite threshold, which was found to be 110 K.

Laser amplifiers in optical displays and micromachining systems

One of the most difficult problems of large-screen projection displays and micromachining systems is overloading of a panel to be projected (for example a liquid crystal panel) with illuminating light. The problem can be solved by using, on the way from a panel to be projected to a screen or to an object to be treated, an optical amplifier with high enough amplification. The prospects of using laser amplifiers in these devices are discussed. Among all laser amplifiers the most suitable for this application are now pulsed metal vapor laser and metal halide laser amplifiers. They have rather high gain enabling amplification in the range from 102 to 104 and high average and peak output power sufficient to illuminate a large screen or to treat a material. The main characteristics of these amplifiers are described. The results of experimental investigations of projection systems with copper, copper bromide, gold and some other metal vapor amplifiers are reported. In all cases good quality amplified images were obtained. Average power at the output of amplifiers was under typical conditions of operation comparable with the output power of a laser with the same amplifying element. Measurements of contrast of amplified images showed that under normal conditions of operation it is close to the contrast of the input picture even at strong saturation of the amplifying medium. The influence of the amplifier saturation is briefly discussed. The results of experiments with TV projection systems using two types of liquid crystal spatial light modulators are presented and prospects of development of large-screen projection displays and systems for micromachining with laser light are discussed.