Calculation of the optical system for process equipment on the basis of high-power fiber laser
Calculation of the optical system for process equipment on the basis of high-power fiber laser
P. A. Nosov, А. O. Shchadko
Features of functioning of optical systems of the process equipment on the basis of powerful fiber lasers are considered. The experimental results show that the distribution of the power density of the laser radiation and the temperature distribution on the optical element of the laser head can be approximated by the Gaussian function. The results of experimental studies of the heating of optical elements from high-purity quartz glass of the Russian production of the grade KS-4V are presented in the formation of radiation from a CW high-power fiber laser. The maximum heating temperature of optical elements at various laser power densities are determined. Expressions are given for analyzing the thermal-optical distortions of the beam at the output of the optical system of laser equipment for technological processes of material processing. Analysis of the optical systems calculated has shown that when heating of lenses made of quartz glass under the influence of high-power laser radiation, the output waist is shifted closer to the protective glass, and its diameter remains practically unchanged. The researches show that when designing of laser optics for the modern technological equipment on the basis of powerful fiber lasers the account of heating of lenses is very important.
Show AbstractThe temperature dependence features of the spectral characteristic of a diode laser with a frequency doubler
The temperature dependence features of the spectral characteristic of a diode laser with a frequency doubler
V. V. Bliznyuk$^2$, O. I. Koval$^2$, V. P. Alekseevich$^2$, A. G. Rzhanov$^1$, A. E. Tarasov$^2$
It was experimentally found that when the ambient temperature changes from 260 K to 345 K, the peak wavelength of the spectral characteristic of a laser diode with a frequency doubler on a KTP crystal is practically not shifted relative to the position it occupied at room temperature. The justification of this phenomenon is given.
Show AbstractExperiment investigating on narrowband intense acoustic noise propagation
Experiment investigating on narrowband intense acoustic noise propagation
M. S. Deryabin$^1$, S. N. Gurbatov$^2$, D. A. Kasyanov$^1$, V. V. Kurin$^2$
Nonlinear effects arising when narrowband noise acoustic beams propagate are experimentally studied. Special experimental setup allows radiating noise acoustic signals with specified characteristics and recording broad frequency range data as the signals propagate. The base of experimental setup is Ultrasound Measurement System Control Centre (Precision Acoustics) with the absolute accuracy positioning no more than 6 microns. Membrane PVDF hydrophone is used for acoustic field registration. The hydrophone is calibrated by manufacturer for frequency range up to 40MHz with non-uniformity no more than 20%. Radiator Olympus with Q factor near 3 is used for radiating noise signals with carrier frequency 2MHz. Typical acoustic pressure level at initial aperture is 1MPa. Experiments show transformation of signal spectrum to universal structure as the signal propagates. The law of spectrum falling in high frequency range is frequency in minus one power.
Show AbstractThe interaction and self-action intense acoustic beams. Theory and experiment
The interaction and self-action intense acoustic beams. Theory and experiment
M. S. Deryabin$^1$, S. N. Gurbatov$^2$, D. A. Kasyanov$^1$, V. V. Kurin$^2$
A series of experiments in the interaction and self-action of intense acoustic wave beams is described. The experimental technique used makes it possible to investigate the propagation of beams at large acoustic Reynolds numbers with high spatial and frequency resolution. The degenerate parametric interaction of intense acoustic beams is considered, the nonlinear amplification of a weak signal on a subharmonic is considered, and the evolution of noise quasimonochromatic beams at large Reynolds numbers is studied.
Show AbstractTheoretical research and experimental demonstration of the possibility of creating a plane-wave regime using a large piezoelectric source.
Theoretical research and experimental demonstration of the possibility of creating a plane-wave regime using a large piezoelectric source.
M. V. Khasanova$^1$, S. A. Tsysar$^2$, D. A. Nikolaev$^1$, O. A. Sapozhnikov$^1$
The possibility of experimental realization of an acoustic field in the form of a traveling plane wave is studied with the purpose of measuring the absorption coefficient and the speed of sound in a propagation medium. To do so, it is proposed to use a flat piezoelectric source and to perform measurements in the pulsed mode at short distances from the radiating surface. As a result of theoretical modeling based on the exact solution of the wave equation on the axis of a circular piston radiator, spatial and time intervals for the existence of a plane wave mode are revealed. It is shown that the proposed method allows to measure the absorption coefficient of ultrasound in liquids and soft biological tissues in the megahertz frequency range using radiators of centimeter sizes.
Show AbstractMethods to improve immunity noise detection and direction finding using a vector-scalar modules
Methods to improve immunity noise detection and direction finding using a vector-scalar modules
G. N. Kuznetsov$^1$, A. F. Kurchanov$^2$
Made direction finding of broadband sources of scalar antenna (SA) and vector-scalar modules (VSM) using processing the flow of power and the new method based on the use of pseudovectors built on the projection of vector vibrational rate (VVV). Investigated method of interference suppression from a local source with using of vector fields.
Show AbstractResearch unidirectional reception, evaluation range and source depth using scalar and vector-scalar antennas
Research unidirectional reception, evaluation range and source depth using scalar and vector-scalar antennas
G. M. Glebova$^1$, G. N. Kuznetsov$^2$
We analyze the spatial spectra at the output of the linear scalar or vector-scalar antenna (SA or VSA) at signal processing methods having a different resolution, consistent or inconsistent with the transfer function of the waveguide. The experiments were conducted in a shallow pool at the stationary location of the antenna and the emitter and in regime of the towing with the moving noise source. VSA, unlike SA, suppresses signals coming on «mirror» petals and has unidirectional direction finding, and at using consistent processing in passive mode uniquely determines the distance and the depth of the source.
Show AbstractTheoretical analysis of a torque exerted by the vortex ultrasonic beam on the absorber located in liquid
Theoretical analysis of a torque exerted by the vortex ultrasonic beam on the absorber located in liquid
M. E. Terzi, S. A. Tsysar, P. V. Yuldashev, O. A. Sapozhnikov
Waves of any nature carry energy and momentum. In certain configurations of wave beams, angular momentum transfer is also possible: the corresponding beams are called “vortex beams”. In this paper, we study the ability of a vortex acoustic beam of the megahertz range to rotate a large-sized absorber (of several dozen wavelengths in diameter) in a liquid. The vortex beam was formed in water by passing ultrasonic radiation from a focusing piezoceramic source through a non-uniform in thickness 12-sector phase plate made from Plexiglas. The beam propagated vertically upward and was directed to an acoustic absorber in the form of a cylinder 10 cm in diameter and 3 cm in height made of silicone rubber. The absorber was freely suspended on a thin elastic thread. It is demonstrated that when the absorber is irradiated, it is rotated. By scanning the acoustic field in the transverse plane by a miniature hydrophone, two-dimensional distributions of the amplitude and phase of the wave were found, and on the basis of these calculations the moment of the radiation beam force applied to the absorber was calculated. The results of the calculations are in agreement with the observations.
Show AbstractUltrasonic gas flowmeters with laid-on sensors
Ultrasonic gas flowmeters with laid-on sensors
A. D. Mansfeld$^1$, A. G. Sanin$^1$, G. P. Volkov$^1$, R. V. Beliaev$^1$, D. V. Moroskin$^2$
Two types of ultrasonic flowmeters with laid-on sensors have been described realizing gas flow measurement through metal pipe wall. The main advantage of developed flowmeters is an ability to measure gas flow without sensor insertion into the wall even at low pressure. Different probing methods (pulse, continuous), "wall" signals influence, useful signal selection methods have been considered. Laboratory and field experimental results are presented.
Show Abstract3D-printing possibilities for the manufacturing technology development of hydroacoustic longitudinal bending type emitters with the complex radiator's body geometry
3D-printing possibilities for the manufacturing technology development of hydroacoustic longitudinal bending type emitters with the complex radiator's body geometry
A. K. Britenkov$^{1,2}$, B. N. Bogolybov$^1$, S. A. Smirnov$^1$, V. A. Perfilov$^1$
Low-frequency hydroacoustic emitters are being used in a wide range of tasks: from long-distance sound communication and remote control to seismoacoustic reconnaissance. Thus the manufacturing of compact high-power radiators emitting in a sufficiently wide frequency band is an actual task. Making the radiator shell is one of the most laborious and complicated technological operations in the process of creating and customizing hydroacoustic transducers. Unrealizable for the ordinary metalworking complex shapes of radiator's body can be produced by layering laser melting (SLM-technology). Making the radiator shell longitudinal bending-type piezoelectric active element by laser 3D-printing of metal powders eliminates the problem of encapsulation, resistance to hydrostatic pressure and reduce the parameters dispersion of the radiator to facilitate its configuration, as well as improve reliability of the transducer.
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