Victor A. Serebryakov

Electro-optical modulators based on KTP crystals for high-power lasers in the mid-IR region

This paper presents the results of experimental studies on the application of the near-IR and mid-IR ranges of KTP-crystal-based modulators in lasers that use birefringence-compensation setups in which the crystallographic axes of the crystals are identically oriented. The chosen setup makes it possible to compensate for not only the natural birefringence of the crystals, but also the thermal distortion induced by laser heating. This made it possible to create modulators with contrast K≥100 for lasers with high average power.

A kilowatt, two-waveguide slab laser

Construction principles and an optical layout have been developed for solid-state diode-pumped lasers based on a two-waveguide slab active element with conductive cooling that allows scaling of the power in the kilowatt range. Prototypes of a two-waveguide diode-pumped Nd:YAG laser with a mean radiation power of up to 1000 W have been investigated. The possibility is discussed of using slab elements made from heat-strengthened neodymium glass to create powerful pulsed-periodic slab lasers.

Development of a kilojoule channel for Nd-glass laser systems with a 70-ns pulse SBS compressor

An optical scheme for a kJ channel of a neodymium glass laser system with SBS-compressor for a 70 ns pulse has been described. The use of a pump pulse of long duration - 70 ns - makes it possible to operate a near-steady SBS mode in compressed gasses. An experimental study of the SBS oscillator-compressor stage with pump focusing and a two- pass pattern has been carried out and a 70 ns, 8 J pump pulse has been compressed down to 1 ns.

Average power limits of diode-laser-pumped Ho:YAG lasers

Evaluations of the average power limits of YAG:Tm-Ho and YAG:Yb-Ho slab-lasers, transversely pumped by the radiation of the laser diode array, are carried out on the base of the detailed study of the energy conversion processes in the active media.

High-average-power double-waveguide slab laser for material processing

Novel principles of design of a diode-pumped solid-state laser with scalable average output power are described. The approach is based on a double waveguide slab (DWS) concept, when laser slab has a waveguide equality both for pump and laser radiation propagation in the orthogonal directions. The advantages of such a scheme are efficient conduction- cooling and scalability of a laser head to the kW range with the high quality of a laser beam. The feasibility of this concept was proved with the model of a DWS Nd:YAG laser at the level of average output power of 10W. The promising possibility to use thermally strengthened Nd-glass for a high average power qcw laser is discussed.

Problem of laser impulse microshaping quality: analysis and synthesis

Today the laser technologies are widely used in the processing of materials, including also the technologies of the precise micromachining. UV and X-ray lasers have very good prospects in the lithography, used for fabrication of chips, while the femtosecond pulsed lasers open the new horizons for the micro- and submicroscribing. But these are the prospects. As for today state-of-the-art, contributing to the application of lasers for these purposes are the numerous advantages of the laser techniques over the traditional methods, such as wide variety of materials separated, possibility of achieving narrow cuts and practically waste-free separation, small heat-affected zone, minimal mechanical effect and minimal thermal deformations, possibility of fast and precise process switch-on and off, possibility of separation along a complex profile in two, or even three, dimensions.

Ablation ability of an erbium laser with a 2.64-μm wavelength during preparation of dental tissues

Using electronic microscope we have studied the opportunity to apply YAG:Cr,Tm-Er laser irradiation (lambda equals 2.64 micrometer) for preparation of the enamel and dentine in different modes of operation. High efficiency of enamel and dentin preparation was shown when using 50 J/sm2 energy density and frequency of pulses proceeding 3-5 n. There was no damaged effects involved teeth hard tissues in our experiences.

Multiwavelength YAG:Nd/Ho laser surgery setups

Elaboration and application to clinical practice of new laser technologies, based on use of high intensity radiation, provided by IR solid-state lasers on the crystals YAG:Nd (1.06 mm and 1.32 mm) and YAG:Ho (2.09 mm), whose surgery action is different, is one of the most important fields of laser surgery. Our experiments, which were carried out on animals, have shown that the treatment methods, based on the use of radiation of these lasers provide the best covering of surgery (general and endoscopic) necessities. The reasons are as follows. On the one hand, one has the possibility to organize loss-free transport of radiation of YAG:Nd/Ho lasers via the fused silica fiber optical waveguide to practically any place in the patients body. On the other hand, various ranges of penetration depths -- from much less than 1 mm to 1 cm -- provides variety of surgery effects. The action of these lasers emission onto the surgery field is well controllable and differential and thus makes it possible to vary its effect just in the course of operation.

Experimental caries treatment using the pulsed erbium laser

The paper summarizes the results of the experiments on the study of the changes in tooth and its pulp, caused by the odontopreparation by the pulsed erbium laser in comparison with the conventional and turbine dental drills. The results evident for the advantages of the laser dental drill application in some cases.

Laser system emitting trains of stable picosecond pulses in visible and UV range of spectrum

The drive laser system of the photoelectric injector for free-electron laser (FEL) is described. This system consists of a 1.064 micrometers mode-locked Nd:YAG oscillator, a pulsed Nd:YAG amplifier chain, Pockels cell electrooptic shutter for selection of part of the amplifier pulse train, KTP frequency doubler and DKDP fourth harmonic generator are used. The bright electron beams required for high performance FELs demand stringent specifications on drive laser output levels, beam quality, and stability. The design specifications, laser architecture, and operating performance are presented.