Publications on the project |
004 Theory of one-dimensional trapping of atoms by counterpropagating short pulse trains |
Authors: | V.I. Romanenko, L.P. Yatsenko | |
Summary: | We have developed a theory of the one-dimensional atomic trap formed by the resonant counterpropagating trains of the short small-area laser pulses. Atoms are trapped in the region
where the counterpropagating pulses ‘collide’. We have derived the effective Hamiltonian which allows us to consider an atom in the polychromatic field of the pulse trains as the atom with the spatially modulated transition frequency in a standing monochromatic wave. We have obtained the expressions for the coordinate-dependent force exerted on the atom and the atom
potential energy. The value of the potential barrier for typical femtosecond laser parameters for an atom with mass ∼100 amu is approximately 15 mK. | |
Keywords: | atomic trap, femtosecond pulses | |
Edition: | Journal of physics B: Atomic, molecular and optical physics | | | 2011,
115305, 7pp,English |
004 Capture of atoms and small particles in an optical trap formed by sequences of counterpropagating light pulses with a large area |
Authors: | V.I. Romanenko, L.P. Yatsenko | |
Summary: | A new trap for atoms and small particles based on the interaction of an atom with the field partially superimposing in time is proposed. Substantial difference from the known analogs is close to adiabatical interaction with field that makes it possible to transfer the larger momentum during the same time and make the trap smaller. It is show that due to dependence of the light pressure force on the velocity the laser cooling of the atom takes place. | |
Keywords: | light trap for atoms, light pulses | |
Edition: | Ukrainian Journal of Physics | | | 2012,
893--900,Ukrainian |
004 Momentum diffusion of atoms and nanoparticles in an optical trap formed by the sequences of counterpropagating light pulses |
Authors: | V.I. Romanenko, A.V. Romanenko, Ye.G. Udovitskaya, L.P. Yatsenko | |
Summary: | The motion of atoms and nanoparticles in a trap formed by colliding pulse sequences is considered. State of the atom is described by the Monte-Carlo wave function approach. The atomic motion is described by classical mechanics. The effect of momentum diffusion due to spontaneous emission of excited atoms and pulsed interaction of the atom with the field on the motion of trapped atoms or nanoparticles is estimated. It is shown that for properly chosen parameters of the atom-field interaction the atomic motion in the trap is slowing, and it
oscillates near antinodes of the non-stationary standing wave formed by counterpropagating light pulses near the point where they ``collide''. | |
Keywords: | Light pressure force, counter-propagating pulses, trap, nanoparticles, Monte-Carlo wave function approach | |
Edition: | Ukrainian Journal of Physics | | | 2013,
438-449,Ukrainian |
004 Laser control of atomic and molecular motion by sequences of counterpropagating light pulses |
Authors: | V.I. Romanenko, A.V. Romanenko, Ye.G. Udovitskaya, L.P. Yatsenko | |
Summary: | The analysis of atomic motion in the field formed by sequences of counterpropagating light pulses reveals the conditions when the field creates the trap in which the temperature of trapped atoms drops to the Doppler limit. The atomic state is described by the wave function using theMonte Carlo wave function method, whereas the atomic motion is considered in the framework of classical mechanics. Laser cooling and trapping is achieved only for non-resonant atom–field interaction. The pulse area does not matter for this effect, in contrast to the repetition period. When the motion of a trapped atom is slowed down, it oscillates around the anti-nodes of a non-stationary standing wave formed by the counterpropagating light pulses at the point where they ‘collide’. The discussed trap is also applicable for trapping and cooling of the molecules for which the matrix of Frank–Condon factors is almost diagonal. | |
Keywords: | light pressure force, counterpropagating pulses, laser cooling, trapping, Monte Carlo wave function method | |
Edition: | Journal of Modern Optics | | | 2014,
839-844,English |
004 Cooling and trapping of atoms and molecules by counterpropagating pulse trains |
Authors: | V.I. Romanenko, A.V. Romanenko, Ye.G. Udovitskaya, L.P. Yatsenko | |
Summary: | We discuss a possible one-dimensional trapping and cooling of atoms and molecules due to their nonresonant interaction with counterpropagating light pulse trains. The counterpropagating pulses form a one-dimensional trap for atoms and molecules and a properly chosen carrier frequency detuning from the transition frequency of the atoms or molecules keeps the temperature of the atomic or molecular ensemble close to the Doppler cooling limit. The calculation by the Monte Carlo wave-function method is carried out for the two-level and three-level
schemes of the atom’s and the molecule’s interaction with the field, respectively. The models discussed are applicable to atoms and molecules with almost diagonal Frank-Condon factor arrays. Illustrative calculations are carried out for ensemble-averaged characteristics for sodium atoms and SrF molecules in the trap. The potential for the nanoparticle light pulses’s trap formed by counterpropagating light pulse trains is also discussed. | |
Keywords: | | |
Edition: | Physical Review A | | | 2014,
053421 (10pp),English |
004 Detrimental consequences of small rapid laser fluctuations on stimulated Raman adiabatic passage |
Authors: | L.P. Yatsenko, B.W. Shore, K. Bergmann | |
Summary: | We discuss the detrimental effect of small rapid random fluctuations of laser-field amplitude and phase upon the efficiency of stimulated Raman adiabatic passage (STIRAP). Such fluctuations typically accompany the laser stabilization procedures that produce nearly monochromatic light on top of a much broader bandwidth Lorentz-profile pedestal which may carry only a few percent or less of the total power. As we will show, their effects differ qualitatively from the fluctuations that have hitherto been considered (for example, phase diffusion). We present analytic expressions for the population transfer efficiency of STIRAP when limited by stochastic fluctuations of this type. These expressions show, in contrast to situations discussed in the past in which population transfer improves with increasing peak Rabi frequencies, that for the weak broadband noise that accompanies a strong narrow-spectral component, there is an optimum value for the peak Rabi frequency and that the effect of fluctuations, although small, cannot be entirely eliminated in practice. The mission of the current work is to point out that, under the given circumstances, efforts in experiments trying to overcome the detrimental consequences of fluctuations by increasing the intensity, which is the intuitively proper approach, will not be successful. | |
Keywords: | | |
Edition: | Physical Review A | | | 2014,
013831 (8pp),English |
004 Cross – correlation Method for the Formation of Laser Energy Fields with Complex Distributions |
Authors: | O.V. Gnatovskyy, A.M. Negriyko, V.O. Gnatoskyy, A.V. Sidorenko | |
Summary: | A new method for the formation of complex spatial distributions of the laser energy over the surface of a flat target is proposed. Its peculiarity consists in that the required phase structure of the laser beam is formed in two stages. After the Fourier transformation, this beam generates the required energy distribution. The method is intended to be used in the optical tweezers probe. It satisfies the main criteria of applicability. In particular, the method provides a small divergence of the beam; it is stable with respect to phase distortions in the optical
path of the probe and adapted to dynamic changes in the field energy distribution by means of controllable phase transparencies. | |
Keywords: | Diffraction field, controllable correlation function, controllable phase transparencies | |
Edition: | Ukrainian Journal of Physics | | | 2013,
122-125,Ukrainian |
004 Holographic Nanocomposites for Recording Polymer–Nanoparticle Periodic Structures: I. General Approach to Choice of Components of Nanocomposites and Their Holographic Properties |
Authors: | T. N. Smirnova, L. M. Kokhtich, O. V. Sakhno, J. Stumpe | |
Summary: | We studied polymerizable nanocomposites for obtaining polymer–nanoparticle periodic structures
by a holographic method. A general approach to choosing components of composites is developed that ensures
a maximal contrast and high efficiency of structures for different types of nanoparticles. We found that the opti-
mal monomeric component of a nanocomposite is a combination of single- and multifunctional monomers with
substantially different reactivities. In this case, the low-reactivity monomer should posses a low viscosity, be a
good solvent for nanoparticles, and have a low thermodynamic affinity to the polymer network formed upon
the polymerization of the high-reactivity monomer. We developed a holographic composition based on known commercially produced monomers that ensures the formation of highly efficient periodic structures for nano-particles of different types. We described the holographic properties of obtained nanocomposites, as well as parameters of bulk gratings recorded in them. | |
Keywords: | | |
Edition: | Optics and Spectroscopy | | | 2011,
133-140,Russian |
004 Holographic Nanocomposites for Recording Polymerframe0 Nanoparticle Periodic Structures: II. Mechanism of Formation of Polymerframe1Nanoparticle Bulk Periodic Structure and Effect of Parameters of Forming Field on Structure Efficiency |
Authors: | T. N. Smirnova, L. M. Kokhtich, O. V. Sakhno, J. Stumpe | |
Summary: | We considered the mechanism by which bulk periodic structures are formed in polymer–nanoparticle nanocomposites. Phase bulk gratings are formed due to the diffusion transfer of nanoparticles between illuminated and nonilluminated regions of a composite upon polymerization in an interference field. We found that, for the majority of studied nanocomposites containing nanoparticles of different natures, the relative modulation of the concentration of nanoparticles exceeds 80%. We showed that the initial composition should be optimized with respect to the mass of nanoparticles, which ensures a maximal recording efficiency at a minimal level of light scattering in the grating. We found that, for each medium, there exist optimal recording conditions (the intensity and period of the field) under which n1 is determined only by the parameters of the medium and does not depend on the parameters of the field. Examples of the practical use of periodic structures based on developed holographic nanocomposites are given. | |
Keywords: | | |
Edition: | Optics and Spectroscopy | | | 2011,
141-148 ,Russian |
004 Simple and high performance DFB laser based on dye-doped nanocomposite volume grating |
Authors: | T.N. Smirnova, O.V. Sakhno, V.M. Fitio, Yu. Gritsai, J. Stumpe | |
Summary: | This paper reports on the optimized design and operation performance of a second order distributed feedback (DFB) dye laser based on an active organic waveguide with a volume Bragg grating. The DFB gratings were inscribed holographically in a dye-doped organic nanocomposite containing high refractive index inorganic nanoparticles. In this work we experimentally investigated and theoretically analyzed the influence of waveguide and grating parameters on the spectral and energy characteristics of this kind of DFB laser in order to obtain a narrow-band emission of low divergence. We will show that a tailored improvement of the waveguide and grating parameters provides a low-threshold laser emission in the spectral range of 570–620 nm with a linewidth of less than 0.05 nm and an output beam profile close to a Gaussian distribution. | |
Keywords: | | |
Edition: | Laser Physics Letters | | | 2014,
125804 (8pp),English |
004 Analysis of light wave diffraction and amplification by reflection grating operating in the second-order Bragg regime. 1. Approximate theory' |
Authors: | V.M. Fitio, T.N. Smirnova | |
Summary: | A new approximate theory was developed and applied to analysis of the second-order Bragg diffraction by a thick reflection grating formed in a medium with and without optical gain. To derive the general system of equations describing the optical wave interaction with a grating the method of constant variation was used that allowed obtaining the analytical formulas for the electric-field strength of transmitted and reflected wave. The proposed approach was extended to the case of grating formed in a material with nonlinear response to the recording field when dielectric permittivity modulation of a medium includes higher spatial harmonics. | |
Keywords: | | |
Edition: | Journal of the Optical Society of America B | | | 2012,
691-697,English |
004 Analysis of light wave diffraction and amplification by reflection grating operating in the second-order Bragg regime. 2. Reflectivity and spectral characteristics of a grating |
Authors: | V.M. Fitio, T.N. Smirnova | |
Summary: | Reflectivity and spectral properties of a thick reflection grating were discussed for the second-order Bragg diffraction regime. With the help of a developed theory analytical expressions were obtained that describe reflection and gain coefficients. A procedure was proposed for determining the wavelength of laser oscillations generated in a grating with gain. The influence of the second harmonic of dielectric permittivity spatial modulation on reflection and spectral characteristics of a grating was also analyzed. Comparison of the approximate results obtained by the proposed approach and by the exact numerical method was carried out and their excellent coincidence was demonstrated. | |
Keywords: | | |
Edition: | Journal of the Optical Society of America B | | | 2012,
944-949,English |
004 Arranging of nanoparticles in polymeric matrix by spatially inhomogeneous laser field |
Authors: | T.N. Smirnova, L.M. Kokhtych, P.V. Yezhov, L.P. Yatsenko | |
Summary: | | |
Keywords: | | |
Edition: | | | | 2014,
52-57,Russian |
The events in the framework of the project |
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004 Executant:Institute of Physics, Department of Physics and Astronomy, Section Physical, Engineering and Mathematics 1. Physics of nanostructures Purpose: Expected results:Issue of new types of products: methods, theories Stage 1: Stage 2: Stage 3: Stage 4: Stage 5:
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