The list of publications 2009-2013

The list of publications for the period 2009 – 2013:

1. Lukishova S.G., Senatsky Y.V., Bykovsky N.E., Scheulin A.S. «Beam Shaping and Suppression of Self-focusing in High-Peak-Power Nd:Glass Laser Systems» / «Self-focusing: Past and Present, Fundamentals and Prospects» Boyd, Robert W.; Lukishova Svetlana G.; Shen, Y.R. (Eds.) Springer Series: Topics in Applied Physics , Vol. 114 (2009)

Methods of the spatial profile formation of laser beams and suppression of self-focusing in the high-power laser systems based on neodymium glass have been considered in this review. The presented material with an extensive bibliography shows that a small-scale laser beam self-focusing is the main mechanism limiting radiation power and brightness in the optical path of the facility. At a beam diffraction on facility apertures in the Fresnel zone the intensity spikes, carried away by self-focusing, appear on the beam profile. Various soft apertures for surge suppression and smoothing of the intensity distribution in laser beams have been examined.

2. Yu.Senatsky, J.-F.Bisson, J.Li, A.Shirakawa, M.Thirugnanasambandam, K.Ueda «Laguerre-Gaussian modes selection in diode-pumped solid-state lasers» // Optical Review 2012, Vol.19, 4, pp.: 201-221

Abstract: The pumping of solid-state lasers by semiconductor diodes has given the new possibilities to form laser beams on Laguerre-Gaussian modes, which are widely used in scientific and applied research. We consider the selection methods of scalar and vector Laguerre-Gaussian modes of lower and higher orders in the laser resonators on crystals and ceramics using inversion profiling in the active medium, intra-cavity lens, axicons, crystal plates, polarization-selective mirrors and others. The beams applications on Laguerre -Gaussian modes of low intensity to control microparticles, to trap atoms, in high-resolution microscopy, etc. are under discussion; the possibilities of using beams on Laguerre-Gaussian modes of high intensity in the research on plasma heating, Accelerator Engineering and Laser Technology are under examination.

3. Yu.Senatsky, J.-F.Bisson, J.Li, A.Shirakawa, M.Thirugnanasambandam, K.Ueda Experiments on Laguerre-Gaussian modes selection in ceramic lasers, // Physica Status Solidi C 2013, Vol.10, 6, pp.: 974–980

Abstract: A study on Laguerre-Gaussian (LG) modes selection in cw and pulsed Nd:YAG or Yb:YAG ceramic lasers pumped by diodes or an external laser source was carried out. Methods of scalar and vector LG modes selection from low to high orders, involving shaping of the pump profile, usage of intra-cavity lenses, uniaxial crystals and polarization selective mirrors, are considered. CCD camera images of beam profiles of hollow scalar LGpm  modes (p-radial, m-azimuth indices) of record high-orders and Bessel-like multi-ring modes with highly directional propagation properties are presented. CW and pulsed ceramic lasers with radially or azimuthally polarized LG vector modes of low and high orders are also demonstrated. Applications of the developed laser schemes and LG beams are discussed.

4. Shelobolin A.V. Inertial propagation of streamers after external voltage termination // American Journal of modern Physics. 2013. Vol.2 №5, pp.242-247.

Abstract: The fundamental processes of streamer propagation in the streamer chamber after external voltage termination are considered on the basis of a plasma-waveguide model of gas electric breakdown. The model analyses the time dependence of streamer radiation under the mentioned conditions. The velocity and time scales of the process have been defined, and the electron density is estimated in the plasma waveguide formed before the external voltage termination. Earlier shortcomings of theories of this phenomenon are corrected.

5. Yu.Senatsky, J.-F.Bisson, J.Li, A.Shirakawa, M.Thirugnanasambandam, K.Ueda Laguerre-Gaussian modes selection in diode-pumped solid-state lasers //
Optical Review 2012, Vol.19, 4, pp.: 201-221

Abstract: Over the last twenty years, diode pumping of solid-state lasers has opened new prospects for the mode control and formation of Laguerre-Gaussian (LG) beams, enabling a large variety of applications. Experiments on scalar and vector LG modes selection in Nd3+-and Yb3+-doped ceramics and crystal lasers carried out at the Institute for Laser Science, Toky are reviewed. Selection of LG modes from low to high orders using intra-cavity elements, polarization-selective mirrors, or shaping the pump beam profile, is considered. Illustrations of record-high-order LG hollow modes, multi-ring modes with highly directional propagation properties, characteristics of cw and pulsed lasers with radially or azimuthally polarized beams of high polarization purity are presented. General solutions of the wave equation for the axi-symmetric electric field, which describe LG beams of various profiles, are proposed for data analysis. In parallel, a short review on LG modes selection studies carried out at other laboratories is given.

6. Thirugnanasambandam M.P., Senatsky Y., Shirakawa A., Ueda K. Multi-ring modes generation in Yb:YAG ceramic laser // Optical Materials 2011, Vol.33, 5, pp.: 675-678

Abstract: A short-focus glass lens with strong spherical aberration was used for mode selection in the cw LD-end-pumped Yb:YAG ceramic laser. Sequence of low to very high order Laguerre–Gaussian (LGpl) modes with different combinations of radial, p and azimuthal, l indices (p =6 -10, l= 6 -28), with output beam diameters 2–13 mm and power up to 30mW was obtained. Peaked and hollow multi-ring beams with near-diffraction free propagation of the central minimum or maximum over 40 m distance from the laser resonator were observed. Mechanisms of mode selection and possible applications of the proposed laser scheme are considered

7. Thirugnanasambandam M.P., Senatsky Y., Ueda K. Generation of radially and azimuthally polarized beams in Yb:YAG laser with intra-cavity lens and birefringent crystal // Optics Express 2011, Vol.19, 3, pp.: 1905-1914 

Abstract:  We demonstrated the operation of cw diode-pumped Yb:YAG laser in radial or azimuthal polarized (RP or AP) beams using a combination of birefringent uniaxial crystal (c-cut YVO4 or α-BBO) and lens as intra-cavity elements. RP and AP doughnut modes (M2 = 2-2.5, polarization extinction ratio 50-100:1) with output power up to 60mW were generated. Apart from doughnut modes, RP or AP ring-like off-axis oscillations and multi-ring beams with mixed RP and AP were also observed at the output of this laser scheme. Using intra-cavity short focus lenses with spherical aberrations AP or RP modes of higher orders was obtained. Mechanism of mode selection in the laser is discussed. The large variety of beams with axially symmetric polarizations from the output of the proposed laser scheme may find applications in different fields.

8. S.D. Zakharov, P.G. Kryukov, Y.V. Senatskiy, S.V. Chekalin, The first experiments to observe neutrons from a laser plasma / "As it was ... Memories of the Laser Engineering creators " Part 3, 2011, pp.: 41-61 (chapter in the monograph)

Abstract: ... The research to obtain a thermonuclear fusion energy through a plasma heating by the powerful lasers (laser thermonuclear fusion, LTF), actively carrying out in recent decades in a number of the developed countries, have been initiated almost half a century ago, in the USSR, in the walls of the P.N. Lebedev Physics Institute...

9. N.E. Bykovsky, Yu.V. Senatsky, Excitation of Periodical Shock Waves in Solid–State Optical Media (Yb:YAG, Glass) at SBS of Focused Low–Coherent Pump Radiation: Structure Changes, Features of Lasing, / Acoustic Waves – From Microdevices to Helioseismology, Marco G. Beghi (Ed.), ISBN: 978-953-307-572-3, InTech (2011), pp. 369-396 (chapter in the monograph)
Abstract:  Description of phenomena observed under the interaction of short intense pump laser pulse of low coherence with optical media and their explanations are presented. The features of SBS and SRS and the appearance of the periodical shock waves in the optical medium at low-coherent pumping are discussed. The interpretation to the observed specific optical damage is given. The mechanism of generation of broadband, high-directional short laser pulses in the spatial structure of thin layers with inversion produced in the region of propagation of intense hypersonic waves in the medium is discussed. Conditions for generation in a 2-mirror resonator containing active medium with a strong refractive index gradient are considered. The interpretation of the observed twisted lines with small-scale structures in generation spectra as well as temporal, spatial-angular characteristics of Yb lasing in the resonator is given.

10. Shelobolin A.V Avalanche: Theory, Experiment, and Their Contradictions / Horizons in Earth Science Research. 2011. pp.341-354. (chapter in monograph).

Abstract: The methodical aspects of an avalanche mechanism of the electrical breakdown of gases are discussed. An avalanche theory and its contradictions with the experiment are considered. Basing on a nonlinear plasma-waveguide model the mechanisms are considered, which may help to overcome the contradictions. The experiments that are advisable to be performed at a modern stage of research are described.

11. Thirugnanasambandam M.P., Senatsky Y., Ueda K. Generation of very-high order Laguerre-Gaussian modes in Yb:YAG ceramic laser, // Laser Physics Letters 2010, Vol.7, 9, pp.: 637-643

Abstract: The use of a simple short-focus plano-convex glass lens with strong spherical aberration for Laguerre-Gaussian mode selection in a cw LD-end-pumped Yb:YAG ceramic laser is demonstrated. Mode selection was obtained in a nearly meter long plane-parallel cavity by shifting an intra-cavity lens of 2.5 cm focal length along the resonator axis. Sequence of Laguerre-Gaussian (LGpl) modes with different combinations of radial (p) and azimuthal (l) indices from low to high orders (p = 0 – 12, l = 0 – 28) with output beam diameters 2 – 13 mm and power up to 30 mW was produced. Along with many low order modes, the whole lineage of very high orders pure “hollow” LGpl modes (p = 5 – 10, l = 7 – 28) were produced by this method for the first time. The region of stability of the resonator with an intra-cavity aberrating lens was found as enclosed between “focusing” and “imaging” configurations in the cavity, which the aberrating lens could provide simultaneously. The mechanism of LGplmode selection in such a cavity and possible applications of the proposed laser scheme are considered.

12. Bykovsky N.E., Senatsky Y.V. Twisted Lines and Small-Scale Structures in Generation Spectra of Yb-Doped Media Excited by Focused Radiation of LiF:F(2)(+) Color Center Laser, // Laser Physics 2010, Vol.20, 2, pp.: 478-486

Abstract: Spectral lines of Yb lasing in 1.03–1.05 μm region structured by 50–200 μm spots were found at focusing a pulsed LiF: F2+color center laser of 0.5–5.0 GW/cm2 intensity on highly doped Yb:YAG or Yb:glass plates in a resonator. Observed features of Yb emission are explained assuming off axis oscillations in Yb laser. Propagation at angles to the axis built at the spectrograph slit a magnified “image” of a structure of generating channels in the active medium. This image projection brought a corresponding structure of spots in Yb spectra. It was found that channels may be formed due to a high-frequency spatial modulation (micrometers scale) of the refractive index profile in samples caused by the oscillating amplitude of thermo-elastic stresses in the pumped medium. Obtained data demonstrate a possibility to study (with high spatial and temporal resolution) non-equilibrium states of materials in small volumes using laser radiation emerging from these objects.

13. Senatsky Y., Bisson J.F., Shelobolin A., Shirakawa A., Ueda K. Circular modes selection in Yb:YAG laser using an intracavity lens with spherical aberration // Laser Physics 2009, Vol.19, 5, pp.: 911-918

Abstract: The possibility of use of ordinary short-focus lenses with strong spherical aberration for mode selection in a laser resonator is demonstrated. Plano-convex spherical lenses with foci from 2.5 to 10.0 cm placed inside the resonator of the CW diode pumped Yb:YAG laser were used to select circular modes of Laguerre–Gauss and Bessel–Gauss type, or to get ring-like, multi-mode off-axis oscillations with variable inner and outer diameters of rings. At the constant pump power mode selection was obtained by shifting an intra-cavity lens along the resonator axis relative to the Yb:YAG ceramics active element of 1.1 mm thickness. Peaked and hollow multi-ring beams with output power up to 30 mW were produced. Near diffraction free (ndf) propagation of the central part (minimum or maximum) of these beams was observed along distances over 10 m from the resonator output coupler. The mechanisms of mode selection due to spherical aberration in the resonator and ndf propagation of output beams are considered. The possibility of producing radially polarized beams from the laser with an intra-cavity lens and possible applications of the devised laser scheme are discussed.

14. Lukishova S.G., Senatsky Y.V., Bykovsky N.E., Scheulin A.S. Beam Shaping and Suppression of Self-focusing in High-Peak-Power Nd:Glass Laser Systems / Springer Series Topics in Applied Physics 2009, Vol.114, pp.: 191-229 (chapter in the monograph)

Abstract: Laser-beam shaping and suppression of beam self-focusing in high-peak-power Nd:glass laser systems are discussed. The role of Fresnel diffraction at apertures at the laser facility as the source of dangerous spatial scales for small-scale self-focusing is illustrated. Methods of the formation of super-Gaussian laser beams for suppressing diffraction ripples on the beam profile and their self-focusing are presented. A brief outline of self-focusing as the primary nonlinear optical process limiting the brightness of Nd:glass laser installations is given. Methods for self-focusing suppression are presented.