Program-2013
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Wednesday, 30 October
10:00 OPENING
- Gennadiy MESYATS, Academician, Director of the P.N.Lebedev Physical Institute, Head of the Electrophysics Department of the MIPT.
Welcome speech
Takashi FUKUDA, Doctor of Science, Member of the Board of Directors of The University of Electro-Communications
Mission Statement and International Strategy of UEC
Kohji ABE, Vice-president of The University of Electro-Communications (Education)
Introduction of the Department of Engineering Science in UEC
11:00 SESSION 1
Chairman Professor Toru MORISHITA, UEC
Invited speaker Oleg TOLSTIKHIN, Professor of the Department of Theoretical Physics, MIPT
Adiabatic theory of ionization of atoms and molecules by intense low-frequency laser pulses.
An introduction to the adiabatic theory will be given. The central concept of Siegert states in an electric field will be explained. First applications of the adiabatic theory in collaboration with Prof. Toru Morishita at UEC and future perspectives will be discussed.
Masayuki KATSURAGAWA, Professor, UEC
Adiabatic manipulation of quantum coherence and its application to extreme nonlinear optical processes
We will give an overview on research project in our group. The key physics is an adiabatic manipulation of quantum coherence which can lead to generation of a set of discrete coherent radiations with an ultrabroad bandwidth. We will also show the future prospect of our research.
Nurul Sheeda Binti SUHAIMI, PhD student, UEC
Ultra-Broadband Raman Frequency Comb with absolute frequency control
We would like to propose a new system to generate an ultra-broadband (NIR-XUV) Raman frequency comb with high accuracy transferred from an absolute frequency and a stabilized carrier-envelope-phase. Such broad, accurate and discrete frequency comb with high spectral intensity has so much potential for attractive applications both in time and frequency domain.
Trivikramarao GAVARA, student, UEC
Raman comb generation with Continuous Wave Laser
We present the generation of rotational Raman comb with CW lasers, the main idea is to put the Para-hydrogen gas inside a high finesse cavity and drive the molecules with their rotational frequency by using two laser frequencies whose difference is equals to the rotational frequency (10THz) of Para-H2. This will lead to very broad, coherent and evenly spaced frequency components which is very useful for precision spectroscopy.
13:00 – 14:00 Lunch break
14:00 SESSION 2
Chairman Professor Oleg TOLSTIKHIN, MIPT
- Invited speaker Toru MORISHITA, Professor, UEC
Ultrafast atomic and molecular dynamics in intense laser fields
We have been theoretically studying on ultrafast atomic and molecular dynamics in intense laser fields in the time scale of atto(10-18) seconds. We will present our recent activities including ones achived in collaborations with Prof. Oleg I. Tolstikhin at MIPT.
Vinh N. T. PHAM, PhD student, UEC
Molecular Seigert states in an electric field
Recently, an efficient method for calculating Siegert states of atoms and molecules in a static electric field within the single-active-electron approximation was established [P. A. Batishchev et al., Phys. Rev. A 82, 023416 (2010)] and applied to calculating ionization rates for molecular targets [L. Hamonou et al., ibid. 84, 053423 (2011)]. In the present work, we further developed the method and established a computer code to obtain the transverse momentum distribution of ionizing electron of molecules derived from the properly normalized eigenfunctions. The method is illustrated for the 1ss and 2pp states of H2+ and the orientation dependence with respect to the electric field is discussed.
Vinh H. TRINH, PhD student, UEC
First-order correction terms in the weak-field asymptotic theory of tunneling ionization
The weak-field asymptotic theory (WFAT) of tunneling ionization in a static electric field [Tolstikhin et al., Phys. Rev. A 84, 053423 (2011)] is developed to the next order in field. The first-order corrections to the ionization rate and transverse momentum distribution of ionized electrons are derived in the context of the single-active-electron and frozen-nuclei approximations. The theory is illustrated for atomic and molecular potentials. The results indicate an extension of the applicability of the WFAT toward stronger fields below the over-the-barrier regime.
Masataka OHMI, PhD student, UEC
Ionization of atoms in ultrashot intense circular polarized laser pulses
We present a theoretical study on ionization of atomic hydrogen irradiated by a few cycle intense circular polarized laser pulses. We solved the time-dependent Shrödinger equation numerically and the resulting photoelectron spectra were compared with the adiabatic theory of ionization [Tolstikhin and Morishita, Phys. Rev. A 86, 043107 (2012)]. We found that the interaction of the ionizing electron with the parent ion play an important role.
Hsumin HUANG, PhD student, UEC
Two-photon break up of collinear Coulomb three-body systems by ultrashort intense laser pulses
We theoretically study two-photon absorption breakup dynamics of collinear Coulomb three-body systems interacting with ultrashort intense laser pulses, where both light-matter interactions and particle correlations play important roles. By analyzing the breakup momentum distributions for various systems having different mass ratios, such as H- (epe), H2+ (pep) and Ps- (ee+e), we could distinguish sequential and non-sequential processes and identify different dominant mechanisms. We also discuss pulse duration dependences of the breakup processes based on the perturbation theory.
Thursday, 31 October
10:00 SESSION 1
Chairman Dr. Inga TOLSTIKHINA, MIPT
Invited speaker Nikolay KOLACHEVSKY, Professor, MIPT
Search for the drift of fundamental constants from astrophysical and laboratory observations
We discuss modern experimental methods which put stringent restrictions on the possible variation of fundamental constants. Spectroscopic observations of astrophysical and laboratory atomic and molecular samples set laminations for the possible drift of the fine structure constant and electron-to-proton mass ratio.
Elena KALGANOVA, student, MIPT
Laser cooling of thulium atoms.
Due to electron structure peculiarity thulium is a promising candidate for frequency standard creation. For this purpose laser cooling and trapping of thulium atoms in the magneto-optical trap (MOT) was performed. The lowest temperature of atomic cloud achieved in MOT is equal to 25 µK. The lower temperatures required for reloading atoms in a weak dipole trap are supposed to be reached by means of second-stage laser cooling.
Dmitry TREGUBOV, student, MIPT
Measurement of the 5D Level Polarizability in Laser Cooled Rb Atoms
We measured the scalar and tensor polarizabilities of both 5D3/2 and 5D5/2 fine structure levels in Rb atom using Stark shift. Rb atoms were laser cooled in a regular six-beam magneto-optical trap, forming a cloud at the center of a plane capacitor. Excitation to the 5D level was performed consequently (5S->5P, 5P->5D) and was measured by spontaneous emission. Our results corresponds to previously published theoretical predictions, but are more accurate.
Kenichi NAKAGAWA, Professor, UEC
Manipulating ultracold atom for quantum technologies
Ultracold atoms are important in the quantum technologies such as precision measurements, quantum information processing. We will review our recent studies about the manipulation of ultracold atoms and BEC and its application to atomic interferometers and quantum information processing.
Naoto WATANABE, student, UEC
Dual-comb spectroscopy using two electro-optic modulator based frequency combs
There have been many demonstrations of dual comb spectroscopy because of its unique properties such as wide spectral range, high resolution and high accuracy. We demonstrate a dual comb spectroscopy using two EOM (electro-optic-modulator) -based optical frequency combs. Comparing with conventional dual comb spectroscopy based on mode-locked lasers, this method enables simple and compact optical setup and also eliminates precise frequency control of two mode-locked lasers.
Mikhail SMAEV, senior scientist, LPI
Orientational optical nonlinearity of nematic liquid crystals
The light field can effectively orient rod-like molecules of nematic liquid crystal. Due to the reorientation the refractive index for extraordinary wave increases and optical nonlinearity is manifested. The nonlinearity is nine orders of magnitude higher than Kerr nonlinearity of ordinary liquids. Doping the nematic liquid crystal with low- and high-molar-mass light-absorbing compounds can significantly enhance and modify the orientational action of the light field.
Dmitry KORSHUNOV, student, MIPT
Sign-inversed optical nonlinearity in polymer-doped nematic liquid crystals
The orientational action of a light beam on nematic liquid crystals (NLCs) doped with azobenzene polymers and monomers was investigated. For the substances studied the complication of the dopant molecular structure results in an increase in the orientational nonlinearity. The latter remains sign-inversed, i.e., depends on the geometry of the NLC and light interaction. The dependence of the enhancement factor (the ratio of light-induced torque in polymer-doped NLCs to the torque in undoped NLCs) on the angle between the light field and director was measured.
13:00 – 14:00 Lunch break
14:00 SESSION 2
Chairman Professor Masayuki KATSURAGAWA, UEC
Sergey TSKHAI, leading scientist, LPI
Advance in Cavity Ring-Down Spectroscopy
New approaches to the method of Cavity Ring-Down Spectroscopy (CRDS) are considering for measurement of small gas impurities in atmosphere. The high spectral resolution in a phase-shift measurement and fast recording of weak absorption spectra in optical cavity using diode tunable laser is obtained.
Andrey KHIZHENOK, student, MIPT
Small absorption measurements by CRDS using the cavity with the light input/output through a mirror hole
A measurements of small absorption by CRDS technique is presented. Compare to conventional version we provide to use the mirrors with a central hole thus ~100% radiation can be inserted in the high quality cavity. LED with 460nm wavelength was used to get spectrum curve and determine concentration of NO2 up to 11±1,5ppbv.
Takashi MUKAIUAMA, Professor, UEC.
Collisional properties of ultracold atoms and ions
Ultracold atoms and ions are ideal quantum systems to study few-body and many-body physics since those systems are free from impurity and provide high experimental controllability. In such systems, elastic and inelastic collisions play very important role in the determination of physical properties of the system especially at ultra-low temperature. In the talk, we will present our recent experimental determination of p-wave scattering parameters of fermionic Li atoms and also observation of elastic and inelastic collisions in ultracold atom-ion hybrid system.
Jun YOSHIDA, student, UEC
Stabilization of magnetic field for precise control of p-wave interactions in ultracold atomic gases
The tunability of inter-atomic interactions makes an ultracold atomic gas a unique and useful model system for fundamental physics. Taking advantage of this technique, we are able to realize an atomic sample with only p-wave inter-atomic interactions, which would make the atomic system ideal for the study of p-wave superfluidity. In order to precisely control the p-wave interaction, magnetic field strength applied to the atomic sample has to be stable and accurate. In this presentation, we will talk about an RF spectroscopy of the atoms to measure the magnetic-field fluctuation and explain how to stabilize the magnetic field with the fluctuation on the order of 1 mG at 160 G.
Munekazu FUJINAGA, student, UEC.
Frequency stabilization of diode lasers using high finesse ULE cavity
Ultracold atom-ion hybrid system has attracted much attention from researchers in the field of low temperature physics and chemistry. We have been devoting much effort to realize ultracold atom-ion mixtures and very recently we successfully measured elastic collision cross-section between trapped fermionic Li atoms and Ca+ ions. However, the long-term frequency stability of the diode laser for cooling ions limits our capability of having stable atom-ion mixtures. In this presentation, we will talk about our recent achievement in stabilizing the diode laser using ULE cavity and the quantitative confirmation of the stability by observing a crystalized state of laser-cooled ions.
Ryoichi SAITO, student, UEC.
Temperature stabilization of ULE cavity to achieve long-term stability in 40Ca+ cooling laser frequency
We investigate ultracold collisions between ions and ultracold fermions in a hybrid system compounded of 40Ca+ and 6Li. To trap ions stably and cool efficiently, both the short-term and long-term stability of the cooling laser frequency for ion traps are important. The short-term stability of the cooling laser is improved by locking the laser frequency to high finesse ULE cavity placed in a vacuum chamber, and the long-term stability is improved by controlling the temperature of the ULE with fluctuation less than 0.02 degree. We quantitatively confirmed the long-term stability of the laser frequency using the Doppler-free spectra of Rb atom as a frequency reference. In the presentation, we describe the detailed scheme of how to measure the frequency stability of the cooling laser for the ion trap.
16:00 Exam Professor Nikolay KOLACHEVSKY, MIPT
Friday, 1 November
10:00 SESSION 1
Chairman Professor Kenichi NAKAGAWA, UEC
Evgeny RAGOZIN, Professor, MIPT
Aperiodic multilayer structures in soft X-ray optics and spectroscopy
We discuss the potentialities of aperiodic multilayer structures as regards reflection of soft X-ray radiation in a broad spectral range, first and foremost at normal radiation incidence, as well as the capabilities of broadband polarizer mirrors. The use of broadband multilayer mirrors in laser-plasma spectroscopic experiments is reviewed. Also considered are the potentialities of multilayer mirrors as instruments of X-ray attooptics.
Alexey SHATOKHIN, student, MIPT
Conception of a hight-resolution stigmatic spectrometr for the 11-30 nm range
We propose the concept of a stigmatic XUV range spectrometer, where we use the aperiodic Multilayer Mirror of normal incidence along with the grazing incidence flat reflecting Varied Lane Space grating. That achieves a unique combination of spectral resolution, spatial resolution and luminosity. The developed methods were improvement over the prior methods. These improvements led us to scale up the value of spatial resolution lossless of luminosity. As the result, we propose spectrometer with 2 order better scale of luminosity as compared with obtain spectrometers with the same scales of spectral and spatial resolution.
Hiroshi SHIMADA, Professor, UEC
Current Induction Phenomena in Capacitively Coupled Linear Arrays of Mesoscopic Josephson Junctions
In a system of capacitively coupled arrays of mesoscopic Josephson junctions, a variety of current induction phenomena can be observed depending on the measurement conditions such as bias voltages, applied magnetic field, and coupling strength. The microscopic mechanisms of most of them, however, are still unclear. Some of such phenomena will be presented.
Koichi TAKEDA, student, UEC.
Towards precise current multiplication by use of linear arrays of small Josephson junctions
We have been exploring to build precise current multipliers by using linear arrays of small Josephson junctions with the objective of a metrological use. In the system of capacitively coupled linear arrays of small Josephson junctions, a current duplication phenomenon, which is called the quantum current mirror effect, can be observed. Based on this effect, we have fabricated a prototype of a 10-fold current multiplier. The overview and the present results on current multipliers will be presented.
Vladimir LEBEDEV, Professor, MIPT
Elena MIRONCHUK, PhD student, MIPT
Resonant electron-transfer processes in collisions of Rydberg atoms with electron-attaching neutral targets
We report the results of comparative studies of ion-pair formation and resonant quenching processes in collisions of Rydberg atoms with electron-attaching atoms and molecules possessing small electron affinities. It is demonstrated that the inclusion of the long-range interaction effects into the calculations of the Rydberg-covalent–ionic coupling terms is crucial for a reliable quantitative description of such processes. For each system under study we find the regions of n in which either the resonant quenching or the ion-pair formation processes are predominant. The cross sections of electron-transfer reactions are shown to be significantly dependent not only on the principal quantum number but also on the orbital angular momentum of Rydberg atom and the anion binding energy. A particular attention is paid to the comparison of the theory with the experiment and to the potential applications of the results obtained to modern studies of weakly-bound atomic-molecular systems.
Tomotake YAMAKOSHI, student, UEC
Ultracold atoms in the combined potential of an optical lattice and a harmonic trap
Recently, ultracold atoms in an optical lattice have been investigated eagerly because of their great promise for numerous applications to coherent manipulation of ultracold atoms. We focus on the production and manipulation of wave packets from ultracold atoms in the combined potential of an optical lattice and a harmonic trap. In the presentation, we show results of numerical simulations and its analysis.
13.00 – 14.00 Lunch break
14:00 SESSION 2
Chairman Professor Evgeny RAGOZIN, MIPT
On the mechanism of angular momentum transfer in electronic excitation of molecules by electron impact
Experiments on electron impact vibronic excitation of molecular hydrogen in gas discharge plasmas and by electron beams reveal significant angular momentum transfer and change in the ratio of ortho/para hydrogen densities. The observed effects are due to excitation via formation of negative intermediate ions. A model of such processes is proposed that provides a quantitative description of experimental results. The results of χ2 –criteria tests suggest that the dominant process is H2(X1Σ+g)+e(p) → H−2(2Πu) → H2(d3Πu, I1Πg)+e′(l). The relative probabilities of ion decay by autodetachment of s, p and other electrons are determined.
Pulse Cathodoluminescence spectra and spectra of luminescence under the influence of Gamma Irradiation
The Pulse Cathodolimnescence spectra of crystalls GSO-7, YAG-Ce(3+), LFS-3 and their spectra under the influence of Gamma Irradiation of Na22 source had been measured. It was stated that visible spectra of Cathodoluminescence and spectra of luminescence under the influence of Gamma Irradiation are identical. This result gives an oportunity to use the Cathodolumenescence for crystall analysys with application at Positron-Emission Tomography.
Photoluminescence of Boron δ-doped SiGe/Si Quantum Wells
Boron δ-doping of a sample with a single Si1-xGex/Si quantum well leads to the appearance of a recombination radiation line of a bound exciton. In the sample with x = 4.5% the binding energy of this exciton is 6 meV and its lifetime is 1200 ns. We show that δ-doping can increase the formation threshold of electron-hole liquid. Based on the photoluminescence spectra the concentration of impurities is estimated.
Multi-channel scintillation diagnostics for extended atmospheric discharge in the ERG installation
Studies of atmospheric discharge leading to the installation of the ERG (LPI) have shown the need for the development of scintillation diagnostics . Low-background check required short pulses study with photon energies from tens of keV to a few MeV, as well as fast neutrons. It is important to provide the most affordable time and amplitude resolution on the available types of photomultipliers and available hardware components. We present the features created by the "fast" scintillation radiation detectors (with a time resolution of 3 ns) on the basis of domestic PMT and plastic scintillators. To provide the desired characteristics has been developed by Zener diode power scheme PMT. In this case, power dividers have been optimized by techniques to eliminate the instability of the PMT associated with a high load average , and the violation of linearity in pulsed response. The results of initial experiments and analysis. Developing a set of detectors will be used in future research , including flight neutron spectrometry started in.