Spin-orbit part of the Λ-nucleus optical potential

The model of one-boson exchange is used to calculate the spin-orbit component of the -nucleus and nucleon-nucleus optical potential. For the hyperon, the spin-orbit interaction is approximately an order of magnitude weaker than for the nucleon.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 102–105, February, 1981.     

Experimental detection of the optical Pendellösung effect

We report observations of periodic oscillatory behavior of the angular selectivity, near the Bragg angle, in volume holographic gratings recorded in a new photopolymerizable glass with high refractive index modulation. We have detected the presence of overmodulation in the intensity distribution of the first diffraction order. The results reported here were achieved by incorporating in the photopolymerizable sol-gel glass zirconium-based high refractive index species at the molecular level. This is the first time that this effect is observed for light diffraction in an amorphous material.     

Theoretical study of the trapping efficiency of an optical tweezers array system

Optical tweezers have been a valuable research tool since their invention in the 1980s. One of the most important developments in optical tweezers in recent years is the creation of two-dimensional arrays of optical traps. In this paper, a method based on interference is discussed to form gradient laser fields, which may cause the spatial modulation of particle concentration. The parameters related to the optical tweezers array are discussed in detail and simulated by the Matlab software to show the influence of important parameters on the distribution of particle concentration. The spatial redistribution of particles in a laser interference field can also be predicted according to the theoretical analysis.     

Combined optical solitary waves of the Fokas—Lenells equation

In this work, we investigate the Fokas–Lenells equation describing the propagation of ultrashort pulses in optical fibers when certain terms of the next asymptotic order beyond those necessary for the nonlinear Schrö dinger equation are retained. In addition to group velocity dispersion and Kerr nonlinearity, the model involves both spatio-temporal dispersion and self-steepening terms. A class of exact combined solitary wave solutions of this equation is constructed for the first time, by adopting the complex envelope function ansatz. The influences of spatio-temporal dispersion on the characteristics of combined solitary waves is also discussed.     

Comment on “On the analytical solution of the optical Bloch equations”

In a recent paper [P.J. Colmenares and J.L. Paz, Opt. Commun. 284 (2011) 5171], analytical solutions of the optical Bloch equations are presented. This paper follows the same procedures as presented in the paper by the authors [H.R. Noh and W. Jhe, Opt. Commun. 283 (2010) 2353] but concludes that their results are substantially different from the results of the authors. We find that the discrepancy results from the wrong initial conditions employed by those authors for one of the Bloch vector components (w), whose initial value must be 1 not 0. We also find that if proper initial conditions are used, there are no discrepancies between the two results.     

Effect of Fe impurity on the optical loss of Nd-doped phosphate laser glass

The optical loss coefficient at 1053-nm wavelength, influenced by Fe ions in N31-type Nd-doped phosphate laser glass, was determined precisely and analyzed in detail. It is found that the optical loss coefficient per unit of Fe concentration (cm-1/ppmw) increases with Fe concentration in the range of 0-300 ppmw, but it approaches a constant as the Fe concentration is larger than 300 ppmw. Such a concentration effect is due to a shift in the redox equilibrium between Fe3+ and Fe2+ ions in the glass. The effect of oxygen pressure, temperature, and variable valence states of other metal ions in glass samples on the optical loss is also discussed.     

Evolution of the optical properties of single-crystal La1−x SrxMnO3

An ellipsometric method is used to study the dispersion of the real ɛ ₁(ω) and imaginary ɛ ₂(ω) parts of the complex dielectric permittivity of single-crystal La_1−x Sr_xMnO₃ (x=0.1, 0.2, and 0.3) for energies from 100 meV to 5 eV at room temperature. It is found that, when lanthanum is replaced by strontium, the optical spectrum changes fundamentally. A shift in the main features of the spectrum of initial LaMnO₃ at 1.9 and 4.7 eV to lower energies takes place, as well as a partial redistribution of the optical-conductivity spectral weight in the band gap region E<1.7 eV. For compositions with x=0.2 and 0.3, a fine structure of the interband absorption is observed against a background of non-Drude optical conductivity at low energies. Fiz. Tverd. Tela (St. Petersburg) 41, 1445–1449 (August 1999)     

A study of the far-infrared optical properties of rexolite?

The far-infrared optical properties of Rexolite 1422 were characterized at the University of Lowell Research Foundation using Fourier transform spectroscopy. The spectroscopic transmission measurements were performed on a 0.0236 thick sample of material over the submillimeter wavelength region from 10 cm^–1 to 360 cm^–1. Using multiple reflection theory for transmission through an etalon, the frequency dependent complex refractive index of Rexolite is reported.     

Maslov’s asymptotic methods in problems of the theory of optical lattices

Application of Maslov’s asymptotic methods to equations that arise in the theory of optical lattices was considered. The occurrence of a small parameter in the Schrödinger equations with potentials of three-dimensional and controlled optical lattice was investigated and the conditions of application of Maslov’s asymptotic methods for solving these equations was determined. Consideration of different conditions imposed on the parameters in these potentials led to the use of two different methods for solving the arising equations: Maslov’s method of a complex germ and Maslov’s operator-valued method of a complex germ. Expressions that can be used to calculate the desired characteristics of the atomic systems under consideration in optical lattices were derived.     

Study on the optical properties of PPV／TiO2 nanocomposites

The optical properties of poly(Phenylenevinylene)(PPV)/TiO2 nanocomposites,prepared via the sol-gel process,were investigated by UV-VIS,FT-IR,FL spectroscopy and TEM.TEM images indicated that the surfaces of TiO2 nanoparticles became rough,and finally formed the connected network as the TiO2 content increased.FT-IR spectra showed the titanium butoxide hydrolyzed to from Ti organic compound,which can result in the connected network of TiO2 nanoarticles.The conjugation of PPV polymer chains can be interrupted by the TiO2 network structure,as evdenced in UV-VIS spectra.The investigation of the PL spectra revealed that the emitted light of the PPV/TiO2 nanocoposites blue shifted wihout fine structure,and the PL intensity enhanced,when the TiO2 net work fromed.These phenomena suggested that the optical properties of the PPV/TiO2 nanocomposites were dependent on the interfacial structure between PPV and TiO2 nanoparticles.2001 Elsevier Science B.V.All rights reserved.     

Contents of the following issues of Opticheskiĭ Zhurnal (Journal of optical technology)

Chronicle

Contents of the following issues of Opticheskiĭ Zhurnal (Journal of optical technology)     

The compensability between the longitudinal andtransverse mismachining tolerance of gratingin the optical pick-up head

In this paper numeric analysis is made to the influence of the longitudinal mismachining tolerance (LMT) and the transverse mismachining tolerance (TMT) of the grating in the optical pick-up head (GOPH) of VCD, DVD, and CD-ROM on the transmissivity and the intensity ratio of the auxiliary light beam to the main read-write light beam (IRAM) by using the general expression of diffraction efficiency obtained from the scalar diffraction theory. On solving GOPH problem, the scalar diffraction theory and the vector diffraction theory are coincident, and the scalar diffraction theory is reliable. The result shows that LMT and TMT can compensate for the inverse effect of IRAM, however, at the expense of reducing transmissivity. As far as GOPH is concerned, the goodness that LMT and TMT can be effectively compensated for is very advantageous in manufacturing of the grating.     

Analisis of inelastic scattering of π-mesons from nuclei within the microscopic optical potential

Cross sections of inelastic scattering of π-mesons from Si, Ni, and Pb nuclei at energy T _lab = 291 MeV are calculated using the distorted wave approximation. The microscopic direct and transition optical potentials are determined by specifying the pion-nucleon scattering amplitude and the nuclear density distribution, where we use the in-medium πN amplitude parameters obtained earlier by analyzing the elastic scattering data for the same nuclei. The cross sections are calculated on the basis of the relativistic wave equation. The deformation parameters of the nuclei are obtained by comparing inelastic scattering cross sections with the appropriate experimental data.     

Optimized loading of an optical dipole trap for the production of chromium BECs

We report on a strategy to maximize the number of chromium atoms transferred from a magneto-optical trap into an optical trap through accumulation in metastable states via strong optical pumping. We analyse how the number of atoms in a chromium Bose–Einstein condensate can be raised by a proper handling of the metastable state populations. Four laser diodes have been implemented to address the four levels that are populated during the MOT phase. The individual importance of each state is specified. To stabilize two of our laser diode, we have developed a simple ultrastable passive reference cavity whose long term stability is better than 1 MHz.     

Influence of spherical anisotropy on the optical properties of?plasmon resonant metallic nanoparticles

We demonstrate the features of the dipole and quadrupole resonant modes in extinction spectra of spherically anisotropic nanoparticles based on full-wave scattering theory. It is found that in a core–shell nanosphere, the introduction of spherical anisotropy in the core leads to a blue shift in resonant wavelengths for small nanoparticles, while, for large nanoparticles (core radius larger than 90 nm), the dipole resonant wavelength remains unchanged with the variation of spherical anisotropy. In addition, the peak strengths for the dipole and quadrupole modes are also studied. Numerical simulations show that the strong localization of electric fields can be further enhanced and tuned by adjusting the spherical anisotropy in the core. In contrast, the anisotropy introduced in the shell results in a blue shift for small nanoparticles but a red shift for nanoparticles with larger size. The tunability of plasmon resonant shifts in extinction spectra and tailored localization of enhanced fields are revealed.     

Anisotropic hyperfine interactions limit the efficiency of spin-exchange optical pumping of ³He nuclei

We use accurate ab initio and quantum scattering calculations to demonstrate that the maximum 3He spin polarization that can be achieved in spin-exchange collisions with potassium (3?K) and silver (1??Ag) atoms is limited by the anisotropic hyperfine interaction. We find that spin exchange in Ag-He collisions occurs much faster than in K-He collisions over a wide range of temperatures (10-600 K). Our analysis indicates that measurements of trap loss rates of 2S atoms in the presence of cold 3He gas may be used to probe anisotropic spin-dependent interactions in atom-He collisions.