A. F. Glova

Bifurcation and chaos in a system of optically coupled CO2 lasers

Bifurcation and chaotic lasing regimes have been observed for the first time ever in a system of optically coupled CO2 lasers. The regions of stable laser mode locking are determined analytically and numerically. The dynamic regimes in the absence of mode locking are calculated. Agreement between experimental and numerical results is obtained.

Influence of water medium and flame on the processes of laser materials treatment

The conditions of drilling and cutting in water of 0.15-mm-thick titanium and stainless steel plates with the radiation of a repetitively pulsed Nd:YAG laser are studied experimentally in the absence of water and gas jets. Measurements of the absorption coefficient of radiation of a repetitively pulsed Nd:YAG laser and of a cw fiber Yb laser by the diffusion flame of aviation kerosene are performed. The radiation power scattered by the flame are measured under flame irradiation by Nd:YAG laser radiation.

Effective phase locking of an array of lasers

It is predicted theoretically and verified experimentally that an effective phase-locking of a two-dimensional array of lasers can be achieved by making use of the reproduction of the wave front of a periodic structure of coherent radiators.

Remote processing of metals with an increased laser radiation intensity

Experimental investigations of the conditions of remote processing of metal plates with a thickness of 1.5–10 mm by radiation of a cw ytterbium fibre laser with the power up to 7.5 kW and radiation intensity varied from 10⁵ to 10⁶ W/cm² have been carried out. It was shown that such main processing parameters as drilling time, maximal velocity and cutting efficiency become appreciably better in comparison with the processing at radiation intensity equal to or less than 10⁴ W/cm².

Effect of radiation refraction on the characteristics of a cw optical discharge

One-dimensional model of a continuous optical discharge is proposed, allowing the estimation of its parameters in a converging laser beam taking into account the refraction of the radiation on the discharge. The influence of spherical aberrations of a focusing lens on the measured thresholds of maintenance of the discharge in the laser plasmatron mode has been discussed.

Coating formation at laser irradiation of a dusty gas medium

A free vertical jet of microparticles in a gas is illuminated by a horizontal focused laser beam. The products of the interaction of particles with radiation are deposited on a heated substrate and form a coating. The substrate is a cathode or an anode at the application of an auxiliary discharge. The parameters of the jet have been calculated and the threshold intensity of laser radiation needed for the evaporation of particles has been estimated. The radiation spectra of the dusty gas medium have been measured and the temperature of particles has been determined. Samples of AlN, Ti, and Ti/AlN coating on steel St.3 have been obtained.

Properties of the interaction of laser radiation with a gaseous dust medium

Radiation power for the combustion of carbon particles is measured at particles irradiation in air by a cw CO2 laser. For the medium in the form of a free vertical jet the dependences of the threshold radiation intensity for the evaporation of aluminium and carbon particles in nitrogen on their radius are obtained.

Mode selection of a linear laser array with an external Talbot cavity

Summary form only given. Possibility of modes selection of linear laser array with an external Talbot cavity by a method of in-cavity square-low phase corrector is experimentally demonstrated. A conjugated telescope consisting of a cylindrical focusing lens and convex mirror was used as a flat equivalent cavity mirror. Beam matrix of a such telescope coincides at certain distance between mirror and lens with a beam matrix of a Talbot cavity. Change in distance between mirror and lens leads to appearance of the variable radius of curvature of an equivalent mirror that corresponds to insertion of the square-low phase corrector into Talbot cavity. For three element laser array the transition from out-in-phase mode to in-phase mode was observed at subsequent increase of the telescope length as well as at variation of the curvature radius of convex mirror. This change in a generation nature corresponds to changes of the calculated eigenvalues of different modes for empty cavity, which are received for laser array used in an experiment.

The arrays of phase-locked lasers

Summary form only. Radiation parameters of 2D-arrays of waveguide CO/sub 2/-lasers synchronised by in-cavity spatial filter method are investigated. The dependencies for phase-locking efficiency and for axial brightness of far-field array radiation rationed to maximal value versus of number N of single lasers in an array, filter parameters and conditions of excitation are received. For all N phase-locking efficiency decreases if filter transparency also decreases because of increasing influences of additional filter introduced cavity radiation losses.

Multibeam waveguide CO2 laser excited by an alternating-current discharge

We report the development of a multibeam laser, excited by an ac discharge in the frequency range approximately 10 to 70 kHz. The results are given of an investigation of the active medium and of the dependence of the output characteristics of such lasers on the discharge tube diameter, pressure in the gas mixture, and frequency of the pumping current.