Selected articles

Selected publications in the indicated topics with participation of staff members of the Sector

1. A.V. Shutov, I.V. Smetanin, A.A. Ionin, A.O. Levchenko, L.V. Seleznev, D.V. Sinitsyn, N.N. Ustinovskii, V.D. Zvorykin, Direct measurement of the characteristic three-body electron attachment time in the atmospheric air in direct current electric field. Appl. Phys. Lett., 103, 034106 (2013).

   Abstract: We report the results of theoretical and experimental study of the characteristic time for three-body attachment of electrons produced by 100 fs UV laser pulse in the atmospheric air in the external DC electric field ranged from 0.2 to 10 kV/cm.

2. P.P. Vasil’ev, A.B. Sergeev, I.V. Smetanin, T. Weig, U.T. Schwarz, L. Sulmoni, J. Dorsaz, J.-M. Lamy, J.-F. Carlin, N. Grandjean, X. Zeng, T. Stadelmann, S. Grossmann, A.C. Hoogerwerf, D.L. Boiko, Mode locking in monolithic two-section InGaN blue-violet semiconductor lasers. Appl. Phys. Lett., 102, 121115 (2013).

   Abstract: Passive mode-locked pulses with repetition frequencies in the range 40 to 90 GHz were observed in blue-violet GaN-based quantum-well lasers without external cavities. The lasers had a two-section geometry with the built-in saturable absorber section. Individual pulses had durations as short as 3–5 ps at peak powers of around 320 mW.

3. I.V. Smetanin, P.P. Vasil’ev, Enhanced longitudinal mode spacing in blue-violet InGaN semiconductor lasers. Appl. Phys. Lett., 100, 041113 (2012).

   Abstract: An explanation of observed enhanced longitudinal mode spacing in InGaN semiconductor lasers has been proposed. It has been demonstrated that e-h plasma oscillations, which can exist in the laser active layer at certain driving conditions, are responsible for the mode clustering effect. Resonant excitation of plasma oscillations occurs due to longitudinal mode beating. The separation of mode clusters is typically by an order of magnitude larger that the individual mode spacing.

4. I.V. Smetanin, P.P. Vasil’ev, D.L. Boiko, Theory of the ultrafast mode-locked GaN lasers in a large-signal regime. Opt. Express, 19(18), 17114 (2011).

   Abstract: Analytical theory of the high-power passively mode-locked laser with a slow absorber has been developed. In contrast with the previous treatment, our model is valid at pulse energies well exceeding the saturation energy of the absorber. This is achieved by solving the mode-locking master equation in the pulse energy-domain representation. The performances of monolithic sub-picosecond blue-violet GaN mode-locked diode laser in the high-power operation regime are analyzed using the developed approach.

5. A.I. Erokhin, I.V. Smetanin, Self-phase modulation in high-power stimulated Brillouin compression. Appl. Phys. Lett., 98, 081115 (2011).

   Abstract: The spectrum of stimulated Brillouin-compressed subnanosecond laser radiation is studied experimentally in a wide range of pump intensities up to the eightfold threshold value. It is found that at intensities increasing four times the threshold, the spectrum splits and acquires a two-humped shape, which is explained by the phase modulation near the Brillouin resonance. An analytical model of self-phase modulation in stimulated Brillouin compression is developed, which describes the observed spectral splitting and formation of the frequency chirp.

6. A.A. Ionin, S.I. Kudryashov, A.O. Levchenko, L.V. Seleznev, A.V. Shutov, D.V. Sinitsyn, I.V. Smetanin, N.N. Ustinovsky, V.D. Zvorykin, Triggering and guiding electric discharge by a train of UV picosecond pulses combined with a long UV pulse. Appl. Phys. Lett., 100, 104105 (2012).

   Abstract: Non-self-sustained electric discharge and electric breakdown were triggered and guided by a train of picosecond ultraviolet (UV) pulses overlapped with a long free-running UV pulse of a hybrid Ti:Sapphire-KrF laser facility. The photocurrent sustained by this train is two orders of magnitude higher, and the electric breakdown distance is twice longer than those for the discharge triggered by the long UV pulse only.

7. V.D. Zvorykin, A.O. Levchenko, A.V. Shutov, E.V. Solomina, N.N. Ustinovsky, I.V. Smetanin, Long-distance directed transfer of microwaves in tubular sliding-mode plasma waveguides produced by KrF laser in atmospheric air. Phys. Plasmas, 19, 033509 (2012).

   Abstract: A new regime of the sliding-mode propagation of microwave radiation in plasma waveguides in atmospheric air is studied both experimentally and theoretically. The mechanisms of air photoionization and relaxation under propagation of 25-ns pulses of KrF laser are investigated. It is shown that a tubular plasma waveguide of large radius (much larger than the wavelength of the microwave signal) can be produced in the photoionization of air molecules by 248-nm radiation of the KrF-laser. We experimentally demonstrate the laser-enhanced transfer of the 38-GHz microwave signal to a distance of at least 60 m. The mechanism of the transfer is determined by the total internal reflection of the signal on the optically less dense wall of the plasma waveguide. Analytical and numerical simulations performed for various waveguide radii and microwave radiation wavelengths show that the propagation length increases with the decrease in the wavelength reaching a few kilometers for submillimeter waves. A medium-size KrF laser facility of about 400-J energy in a train of picosecond pulses is suggested for the directed transfer of microwave radiation to a 1-km distance.

8. I.V. Smetanin, Dissipative and non-dissipative solitons in the SRS-backscattering of laser radiation in underdense plasma. Laser-driven Relativistic Plasmas Applied to Science, Energy, Industry and Medicine – The 3rd Int. Symposium, Eds. S.V. Bulanov, A. Yokoyama, Yu.I. Malakhov, Y. Watanabe. AIP Conf. Proc., 1465, 107–112 (2012).

   Abstract: The process of stimulated Raman backscattering of a laser pulse in underdense plasma is considered self-consistently in a 1D model. Solutions to this problem in the form of backward-propagating bright solitons (the Stokes scattered pulse and the plasma density wave) coupled with the dark soliton in the pump laser pulse are found. These solitary solutions exist both in the non-dissipative (non-collisional plasma) case and in the dissipative (collisional plasma) case.

9. A.V. Кozlovskii, Mechanism for quantum noise suppression in a multimode laser. J. Physics: Atom. Mol. Opt. Physics, 45, 025401 (2012).

   Abstract: The mechanism for quantum noise suppression in a multimode laser with a homogeneously broadened line is explained. It is shown that the spontaneous emission noise and pump noise contribution to the photon number fluctuations inside the laser cavity may be suppressed infinitely (up to their complete elimination) when the number of modes participating in the generation is increased. Low-frequency spectral squeezing for an individual output field mode in optimal conditions tends to 100% as the total number of modes increases. The low-frequency spectral squeezing for the total output field may reach 50% below the shot noise level under optimal conditions. The noise suppression of the laser light is explained by the saturation effect of an atomic transition and inter-mode correlation. A multimode laser is an accessible source of light with potentially fully suppressed quantum noise.

10. A. V. Kozlovskii, Quantum equations of motion for multi-mode laser generation with account for the spatial dependence of the interaction of atoms with the field. Teor. Mat. Fiz., 167(1), 96–110 (2011).

    Abstract: We obtained equations of motion for electromagnetic field operators for a three-level multi-mode laser with account for the spatial dependence of the interaction of atoms with the standing wave field in the cavity. The dynamics of the average values of the numbers of photons in the modes of the field and the correlation function of the modes of the field were calculated and analyzed. The effect of intermode correlations on the dynamics of settling the laser stationary generation was investigated. It was found that the account for the spatial dependence of the interaction of atoms with the field and intermode correlations in studies of the average values of the numbers of photons led to reveal new properties of laser generation, such as the saturation of intensity of laser emission in single-mode regime and the generation of short light pulses of side subthreshold modes with amplitudes depending on the initial state of the field in the cavity.

11. V.A. Alekseyev, Statistics of mesoscopic ensembles of bosons and fermions. ZhETF, 139(6), 1066–1073 (2011).

    Abstract: We found the equilibrium distribution functions for ensembles of bosons and fermions with a limited number of particles. The distribution functions for numbers of particles in different quantum states were shown to be statistically dependent and only at a large number of particles in an ensemble this dependence vanished. At a high temperature, the found distributions pass into the Boltzmann distribution; and at a large number of particles in an ensemble, into the Bose–Einstein and Fermi–Dirac distributions.

12. I.E. Protsenko, Theory of the dipole nanolaser. UFN, 182(10), 6–12 (2012).

    Abstract: The paper theoretically investigates the coherent generation of the dipole moment of a metal nanoparticle at the excitation of a localized plasmon resonance in it by means of an oscillator (atom, quantum dot, etc.), in which the inverse population of electron states is provided for. The oscillator and the nanoparticle interact via the near field. This nanosized system – a “dipole” nanolaser (DNL) – emits a coherent electromagnetic field under the threshold conditions fulfilled. The basic and simplified DNL equations are deduced, the threshold conditions of generation and the DNL features associated with the noncoherent generation of the dipole moment are discussed, some instruments based on the DNL are also discussed: broadband optical modulators, high-efficiency light-emitting devices, as well as possible DNL circuits and further directions of their studies.

13. I.E. Protsenko, A.V. Uskov, Photoemission from metal nanoparticles. UFN, 182(5), 543–544 (2012).

    Abstract: The approach of A.M. Brodsky and Yu.Ya. Gurevich is generalized to photoemission from metal nanoparticles at the excitation of a localized plasmon resonance (LPR) in them. The cross section and the probability amplitude of photoemission from a nanoparticle are obtained analytically, taking into account the LPR excitation and the electromagnetic field and photoelectron mass changes at the metal–environment interface. An increase by two orders of magnitude in the photocurrent from a layer of Au nanoparticles to silicon compared to a bulk Au layer is predicted due to an increase in the electromagnetic field strength under the excitation of LPR and due to a significant part of the nanoparticle surface being nonparallel to the incident field polarization. Practicable applications of the results include improving the performance of photocells and photodetectors, and probably reducing the minimum photoeffect time. 

14. A. Pors, A.V. Uskov, M. Willatzen, I.E. Protsenko, Control of the input efficiency of photons into solar cells with plasmonic nanoparticles. Opt. Commun., 284, 2222–2225 (2011).

    Abstract: We study numerically the photon input efficiency of silicon solar cells due to gold plasmonic nanoparticles deposited on the cells. At low densities, when collective effects in light scattering by the nanoparticle ensemble are negligible, the absorption dependence increases linearly for a significant range of the solar spectrum. Collective effects lead to that the input efficiency saturates, reaches its maximum and then decreases with nanoparticle density. The maximal input efficiency depends on the photon wavelength, nanoparticle shape and size, their distance to the cell and cell thickness, and can reach ~95% in thick solar cells. Finally, we show that aluminum nanoparticles improve the input efficiency in comparison with gold nanoparticles.

15. A.V. Uskov, C. Meuer, H. Schmeckebier, D. Bimberg, Auger capture induced carrier heating in quantum dot lasers and amplifiers. Appl. Phys. Express, 4(2), 022202-1-3 (2011).

    Abstract: Carrier heating in quantum dot (QD) devices, which accompanies Auger capture of carriers from a carrier reservoir to discrete QD levels, is considered for the first time. Equations for carrier dynamics of QD structures are formulated and analyzed by taking into account the carrier heating. A numerical example shows that heating of carriers in a carrier reservoir of a QD structure can be much higher than that of bulk and quantum well devices. Auger capture carrier heating in QD devices can lead to a longer (more than a factor of 2 for the 90% recovery time) relaxation time from a carrier reservoir to QDs.

16. C. Gritti, A. Novitsky, R. Malureanu, A.V. Lavrinenko, A.V. Uskov, B. Kardynal, Absorption enhancement in metal nanoparticles for photoemission current for solar cells. Proc. SPIE 8438, 84380K (2012); http://dx.doi.org/10.1117/12.922445.

    Abstract: In order to improve the photoconversion efficiency, we consider the possibility of increasing the photocurrent in solar cells exploiting the electron photoemission from small metal nanoparticles into a semiconductor. The effect is caused by the absorption of photons and generation of local surface plasmons in nanoparticles with optimized geometry. An electron photoemission from metal into semiconductor occurs if photon energy is larger than the Schottky barrier at the metal–semiconductor interface. The photocurrent resulting from the absorption of photons with energy below the bandgap of the semiconductor added to the solar cell photocurrent can extend the spectral response range of the device. We study the effect on a model system, which is a Schottky barrier n-GaAs solar cell, with an array of Au nanoparticles positioned at the interface between the semiconductor and the transparent top electrode. Based on the simulations, we chose to study disk-shaped Au nanoparticles with sizes ranging from 25 nm to 50 nm using electron beam lithography. Optical characterization of the fabricated devices shows the presence of LSP resonance around the wavelength of 1250 nm, below the bandgap of GaAs.

17. I. Protsenko and A. Uskov, Photoemission from metal nanoparticles. Chapter 8 in the book “Electromagnetic Radiation”, ISBN 978-953-51-0639-5, edited by Saad Osman Bashir, Publisher: InTech, 2012; http://www.intechopen.com/books/electromagnetic-radiation/photoemission-from-metal-nanoparticles.

     

18. A. Novitsky, A.V. Uskov, C. Gritti, I.E. Protsenko, B.E. Kardynał, A.V. Lavrinenko, Photon absorption and photocurrent in solar cells below semiconductor bandgap due to electron photoemission from plasmonic nanoantennas, Progr. Photovoltaics: Res. Applications, DOI: 10.1002/pip.2278, 2012.

    Abstract: We model the electron photoemission from metal nanoparticles into a semiconductor in a Schottky diode with a conductive oxide electrode hosting the nanoparticles. We show that plasmonic effects in the nanoparticles lead to a substantial enhancement in photoemission compared with devices with continuous metal films. Optimally designed metal nanoparticles can provide an effective mechanism for the photon absorption in the infrared range below the semiconductor bandgap, resulting in the generation of a photocurrent in addition to the photocurrent from band-to-band absorption in a semiconductor. Such structure can form the basis of the development of plasmonic photoemission enhanced solar cells.

19. M.T. Crowley, J. Houlihan, T. Piwonski, I. O’Driscoll, D.P. Williams, E.P. O’Reilly, A.V. Uskov, G. Huyet, Refractive index dynamics of InAs/GaAs quantum dots. Appl. Phys. Lett., 103, 021114 (2013).

    Abstract: The refractive index dynamics of an InAs/InGaAs/GaAs dots-in-a-well semiconductor optical amplifier is calculated and compared with experimental results. The fast and slow recovery timescales together with the behaviour with increasing injection are reproduced and explained in terms of the density of carriers available in upper quantum dot and continuum states. Also, a Coulomb-mediated shift of the dot susceptibility is suggested as responsible for the fast recovery of the phase.

20. R.Sh. Ikhsanov, I.E. Protsenko, A.V. Uskov, Increasing the efficiency of organic solar cells using plasmon nanoparticles. Pis’ma ZhTF, 39(10),1–8 (2013).

    Abstract: Using numerical modeling, we showed that, at the introduction of aluminium nanoparticles into one of the layers of an organic solar cell with the bulk heterojunction, the rate of exciton generation in the active layer of the cell increased. Calculations of the absorption in the solar cell, performed in the approximation of the efficient refractive index by the Maxwell–Garnett model, yield a maximal relative value of exciton generation rate increase of 4%.

21. A.V. Uskov, I.E. Protsenko, N.A. Mortensen, E.P. O’Reilly, Broadening of plasmonic resonance due to electron collisions with nanoparticle boundary: а quantum-mechanical consideration. Plasmonics, Sept. 2013, DOI: 10.1007/s11468-013-9611-1, http://link.springer.com/article/10.1007%2Fs11468-013-9611-1.

    Abstract: We present a quantum mechanical approach to calculate the broadening of plasmonic resonances in metallic nanostructures due to collisions of electrons with the surface of the structure. The approach is applicable if the characteristic size of the structure is much larger than the de Broglie electron wavelength in the metal. The approach can be used in studies of plasmonic properties of both single nanoparticles and arrays of nanoparticles. Energy conservation is insured by a self-consistent solution of Maxwell’s equations and our model for the photon absorption at the metal boundaries. Consequences of the model are illustrated for the case of spheroid nanoparticles, and results are in good agreement with earlier theories. In particular, we show that the boundary-collision broadening of the plasmonic resonance in spheroid nanoparticles can depend strongly on the polarization of the impinging light.

22. I. Protsenko, Linewidth of dipole nanolaser. 4th Int. Topical Meeting on Nanophotonics and Metamaterials, 3–6 January 2013, Seefeld, Austria (2013).

    Abstract: Dipole nanolaser, DNL [PRA73, 069902 (2005)] linewidth Gd is found following [PRA59, 1667 (1999)]. Gd is reduced below the localized plasmon resonance linewidth Gl of metal nanoparticle in DNL at a high pump rate Gp>Gl.

23. I.Е. Protsenko, Quantum theory of dipole nanolaser. J. Russian Laser Res., 33(6), 559–577 (2012).

    Abstract: We generalize the semiclassical model of the dipole nanolaser (DNL) based on the Heisenberg–Langevin approach, taking into account the spontaneous emission of plasmons into the generation mode, nonlinearity of generation, and noises. We find a thresholdless smooth transition from spontaneous emission to stimulated emission and the threshold conditions for such a transition and determine the spectrum of generation and its linewidth. We show that, in spite of the very low quality of the DNL generation mode, the linewidth of a DNL with many M ∼ 104−105 emitters decreases, with the pump increase, to quite small values ∼10−2 of the width 2Γ2 of the lasing transition at modest pump rates, about 30 times larger than the decay rate of the emitter upper lasing state. This fact confirms the practical possibilities of realizing DNLs with narrow-line stimulated emission. Otherwise, the linewidth of DNLs with small M ∼ 1 number of emitters is larger than 2Γ2 and increases with the pump rate. In addition, our results on DNLs can be applied to other lasers, such as nanolasers, microlasers, and LEDs for lighting, also with a low-quality cavity and strong spontaneous emission into the generation mode.