Photonics of micro and nanostructures

Dr. Oleg Usov

Current research focus
Recent publications
Research activities
Contact information


The main interests of Dr. O.A. Usov are focused on studies of physical properties of micro and nano size photonic crystal structures: band structure, dispersion, band gap and related optical properties for 1,2 and 3-dimension in inorganic or organic materials. The main goal is to develop theoretical methods and computational techniques to study physical aspects of photonic effects, controlling the properties of optical modes and light-matter interactions, for optimisation of the photonic based optoelectronic devices and also for analysis of optoelectronic properties of the micro and nanostructures.

Current research focus

  • 2D Macroporous silicon
    Two-dimensional macroporous silicon based photonic crystals (PhC) with 4 and 12 micrometer lattice constants and triangular (HCP) pattern of air or liquid crystals (LC) encapsulated pores were made (E.V.Astrova, PTI) and studied by FTIR spectroscopy (T.S.Perova, University of Dublin, Triniti College, Ireland, A.G.Tsvetkov, IVS). A ferroelectric mixture SCE-8 or triphenylene based discotic H7T-NO2 were infiltrated by means of capillary effect to the isotropic phase. Strong intensity enhancement of the low-frequency (600-900 cm-1) vibrational bands were detected and assigned to the photonic confinement effects

  • Photonic crystal based optoelectronic structures and devices
    Photonic crystal structures and microcavities are expected to be applied for enhancement of the radiation of light source and dramatic improvement of optoelectronic devices such as zero-threshold and low-noise semiconductor lasers, light emitting diodes and tight-bending waveguides for optical integrated circuits.
    2D PhC structures have attracted a great attention due to simplicity in fabrication We investigate now a lasing oscillation from several lowest photonic band gap edges in a defect-free PhC (III-V materials and quantum dots (QD) as active media) to determine the in-plane propagation characteristics of lasing modes, its diffraction coupling to the radiation perpendicular to the 2D plane and the relationship between laser feedback mechanism and the photonic band gap edges.
    The problem of efficient extraction from the LED in the vertical direction is coupled to that investigations because the guided modes which phase matching to radiation modes become leaky resonances of PhC at specific band edges leading to higher light extraction

Recent publications

  1. T.S.Perova, J.K.Vij, A.G.Tsvetkov, E.A.Astrova, O.A.Usov, A.G.Tkachenko, Photonic Effects in Macroporous Silicon with Discotic and Ferroelectric crystals. Symposium S: Current Trends in Nanotechnologies. From Materials to Systems. EMRS-2001, Spring Meeting, 5-8.06.2001, Strasbourg,France, Abstract, S/PL05
  2. T.S.Perova, J.K.Vij, A.G.Tsvetkov, E.A.Astrova, O.A.Usov, A.G.Tkachenko, IR absorption spectra of LC confined in the channels of Macroporous Silicon Int. Symposium Nanostructures: Physics and Technologies, 18-22.06.2001, St.Petersburg, Russia, Abstracts, p.432
  3. O.A.Usov, A.V.Klochkov, A XFSWIN program for EXAFS analysis of matter. RSNE-2001, III National Conference for Appl.of X-ray, Synchrotron, Neutron and Electron Radiation to Material Studies, 21-25.05.2001, Moscow, Russia, p.435

Research activities

Photonics and Quantum Electronics
The concepts and ideas that have been successfully applied in analyzing Bragg diffraction of x-ray for atomic structure analysis, photoelectrons for EXAFS local structure analysis and etc now with some extension are effectively used for study microwave and photon diffraction properties of artificial structures well known as photonic crystals (PhC) or photonic band gap (PBG) materials which can be made from a lattice of high-refractive index materials regularly embedded within a medium of a lower refractive index or vice versa.For creating PhC for optoelectronic devices it's usually used state-of-the-art semiconductor microfabrication technique and for this reason theoretical analysis and computer modelling of PhC structures is also a very important area of reseach to prevent expensive fabrication errors and to make more effective analysis of experimental results.
From the preliminary numerical FDTD calculations of photon dispersion and transmition of 2D macropores Si-based (mpor-Si) PhC we have found that the enhanced absorption lines are in the range of dispersion peculiarities specific for heavy photons. The electrical and magnetic fields were calculated from Maxwell equations by means of space transfer matrix (STM) methods, the dispersion relations being determined by diagonalisation of STM, the transmission/reflection coefficients - by transformation of STM to plane wave basis. To get a physical insight into photonic and PBG properties of hcp mpor-Si, InAs/GaAs QD Laser and LED structures we made symmetry analysis of the photonic states at high symmetry points of Brillouin zone and found PBG edge energy dependence on hole diameter and lattice vectors. It permitted to check numerical FDTD calculations and optimised the design and parameters of the photonic structure.

X-ray absorption fine structures and local structure analysis
XfsWin is an interactive program running under Windows'9x/NT which includes all conventional EXAFS data treatment steps: background subtraction , E0 edge and mu0 atomic absorption fitting , fast Fourier transform in k and R spaces (several window functions and k-weighting options, variable step etc.). An experimental photoelectron phase shifts and backscattering amplitudes from standard compounds as well as theoretical ones can be used for single-scattering plane-wave least square refinements to optimize standard parameters of selected atomic model. Application of MSDS C++ and MFC leads to development of an effective Windows interface program for EXAFS data analysis.

References

  1. Se Ahn Song, Jae Cheol Lee, K.Yu. Pogrebitsky, O.A. Usov, XAFS of mixed titanium dioxides, IUCr-17 Congress, Seattle, 18-25 Aug. 1997, WA, USA, Collected Abstracts, Rep.No. PS10.03.17, p.C-371
  2. O.A. Usov, K.Yu. Pogrebitsky, B.T.Melekh, Se Ahn Song, Jae Cheol Lee, Jin-Hak Choi, XANES and EXAFS of Total Electron Emission Yield measurements of TiO2 and Ti1-xNbxO2, NATO-workshop, 4-8 Aug. 1997, St.Petersburg, Collected Abstracts, p.36
  3. S.A.Song, J.H.Kim, J.C.Lee, J.H.Cho, K.Ju. Pogrebitsky, L.A.Bakaleinikov, Yu.N.Yuriev, O.A. Usov, A new Theoretical Approach and a New Device for Electron Emission Induced by X-Ray,"The Electron", Proc.Int.Centennual Symposium on the Electron, 15-17 Sept.1997, Cambridge, UK, pp.557-565
  4. O.A. Usov, K.Ju. Pogrebitsky, B.T. Melekh, Yu.N. Yur'ev, X-ray absorption fine structure of titanium oxides and nitrides, Int. Conf.Physics at the Turn of the 21st Century, Summaries, p. 71
  5. O.A. Usov, K.Ju. Pogrebitsky, B.T. Melekh, Yu.N. Yur'ev, X-ray absorption fine structure of Ti K-edge in Ti1-xNbO2, Fizika tverdogo tela or Sov.Solid State Physics/, vol. 41, No. 5, 1999, pp. 894-896
  6. Usov O.A.,N.F.Kartenko, S.I. Goloschapov, Yu.G.Nosov, Structure and superconducting properties of R1-xYxBa2 (Cu,Al)3O6+y, (R=Eu, Nd) compounds, Fizika tverdogo tela or Sov.Solid State Physics/, vol. 36, No. 8, 1994, pp. 2328-2338
  7. O.A.Usov, I.V.Rozhdestvenskaya, I.I.Bannova, G.G.Abashev, V.S.Russkikh, N.F.Kartenko,Crystal structure of bis(oxapropylendithio) tetrathiofulvalene pentaiodide, ((C4H4OS4)2C2)I5, Zeit.Krist. 211, 1996, pp.260-1 (Int.Crystal struct.Database: CSD-No.402107)
  8. I.V.Rozhdestvenskaya, I.I.Bannova, G.G.Abashev, V.S.Russkikh, O.A.Usov, Crystal structure of bis (beta-(N-pyridyl)ethylthiouronium) bis ( 7,7',8,8' tetra-cyanoquinodimethane) triiodide, (C8H13N3S)2I3, Zeit.Krist. 211, 1996, 258-9 (CSD-No.402106)

Contact Information

Dr. Oleg A. Usov
Phone: +7 812 247 9152
E-mail: oleg.usov@pop.ioffe.rssi.ru

Nanoscale structures and devices group
Laboratory of nonequilibrium processes in semiconductors
Ioffe Institute, Russian Academy of Sciences
Politekhnicheskaya 26,
St.Petersburg, 194021 Russia