Victor V. Vasiltsov

New kilowatt waveguide CO 2 process lasers with high radiation quality

This paper presents a type-series of kilowatt waveguide CO2 process lasers with high radiation quality. The technical advantages and prospects of using such systems for laser processing are discussed.

Development of technologies for layer-by-layer laser synthesis of 3D parts in Russia and Belarus

A brief overview of currently available methods applied in laser synthesis of 3D parts is presented, which range from stereolithography making use of liquid photopolymers to selective laser sintering of metal powders aimed at production of the parts of complex topology.

High-power CW CO2 lasers for material processing

Strict requirements of modern industry and medicine to laser beam quality, stimulated to fulfil a lot of special researches have been undertaken concerning: a) gas discharge stability and uniformity; b) enhancement of active medium optical nonuniformities in the presence of laser generation; c) new concepts of optical resonators; beam power modulation with a controllable coupling mirror. As the result of these investigations, several series of fast-flow and of diffusion-cooled waveguide industrial CO2 lasers in 0.5 to 10.0 kW beam power range have been designed in the IPLIT RAN.

Waveguide high-power industrial CO2 lasers

Experimental, engineering and modeling aspects of development of high- power industrial waveguide single-beam CO2 lasers are considered. Parameters of an experimental model of this type laser with 0.5 kW beam power are presented and relevant critical problems are discussed. Beam output characteristics depending on different parameters are offered.

High-power waveguide industrial CO2 lasers

The paper considers the experimental, engineering and model-physical aspects of development of high-power waveguide single-beam carbon-dioxide lasers for industrial applications. As an illustration, the parameters of the developed experimental model of this type of laser with 0.5 kW average beam power are presented and relevant critical problems are discussed. The results of inquiry into beam output characteristics are offered depending on different parameters. Main technical and economic data have been obtained.

Spatial structure of focused beams in high-power fiber and CO 2 lasers and peculiarities of their application in cutting

The requirements for quality parameters in radiation of different wavelength (i.e. CO2 lasers and fiber lasers) have been defined so as to perform efficient oxygen-free gas laser cutting of large-thickness samples. The main channels of consumption of radiation power in the cutting process have been considered. It is noted that focused beam divergence not only decreases the cutting speed, but also causes cutting quality deterioration.

Main thermophysical processes in laser beam buildup welding of metal powders

The energy balance of laser beam buildup welding of powders is analyzed. Comparison of the obtained results with the experimental data shows that a significant portion of the absorbed power of the laser beam is consumed for evaporation the of powder. A procedure of selection and optimization of laser beam buildup of powder is proposed. It is established that the thermal conductivity and thermal diffusivity of powder can increase significantly within its melting owing to subsequent formation of thermal contact between the melt and underlying layer of powder particles. The range of the Péclet numbers corresponding to high efficiency of laser beam buildup welding of powders is determined.

The lasers for TMLR application

The paper presents the analysis of the requirements to the laser systems used to cure the ischemic disease of the heart by the method of transmyocardial laser revascularization (TMLR). Among the medical laser systems under discussion (solid-state Nd:YAG, Er:YAG, Ho:YAG, excimer lasers, etc.) the high-power CO2 laser with pulse energy to 40 J is most suited to produce channels in the heart muscle. The paper provides the description and the technical characteristics of medical laser systems of “Perfocor” series, based on high-power waveguide CO2 lasers with pulse energy to 60 J, developed at ILIT RAS. The methods to determine the time of laser radiation penetration through the myocardium/blood boundary have been briefly discussed. The application of the “Perfocor” system in other laser operations on blood-filled organs has also been discussed.

Opto-acoustic spectroscopy diagnostics of bubble formation in blood during laser TMR

The mechanism of channel punching in the heart muscle (myocardium) by a pulse of high-power CO2 laser was studied. Water, PMMA and biotissue of animals were used as the models. Diagnostics of the punching process was performed by the methods of registration of sound vibrations in the air and back scattering of laser radiation. It has been revealed that at channel punching in various media, sound vibrations are excited in the spectrum region from 1 to 3.5 kHz, which are due to turbulent pulsation of vapor- drop flow ejected from the channel. The spectrum of acoustic vibrations depends on positions of the channel bottom and is sensitive to the boundary between the myocardial tissue and blood. The measurement of sound vibrations spectra can serve as the basis for diagnostics of the process of channel punching in myocardium.

Using diffraction optics for formation of single-lobe far-field beam-intensity distribution in waveguide CO2 laser synchronized arrays

The arrangements for formation of single-lobe beam intensity of waveguide CO2-laser synchronized arrays using diffraction optics have been discussed. The results of some experiments have been presented to show these arrangement possibilities.