Table of contents

We show the spectrochronography as an efficient tool to extend the THz time domain technique. Assuming that all the information is contained in the time-dependent electric field we apply a windowed transfer technique to measure the instantaneous spectra evolution. As an example, surface electromagnetic waves on the metal grating are considered. Dynamics of surface wave spectral component is measured.

Rhodamine 6G has been used as a fluorescence probe in AOT reversed micelles systems with the different amounts of solubilized water (hydratation power ω). The saturation of fluorescence and the lifetime of dye molecules were measured. The absorption cross section values were calculated from the saturation curves. We showed the differences in values of the absorption cross section, lifetime and velocity of fluorescence saturation in micellar phase with different ω and in comparison to bulk phase. Additionally, the structure of hydrated reversed micelles has been studied by the method of correlation spectroscopy. The influence of ω on size and shape of micelles was detected.

Two-photon excited near field images of hexaphenyl nanofibers are obtained using a scanning near field optical microscope in transmission configuration. From polarized measurements the orientations of the molecular basis units of the fibers are determined with a resolution of better than 400 nm. The molecular orientation angles obtained are comparable to results from two-photon scanning far-field microscopy, but the present measurements provide a better spatial resolution. From this near-field data it is concluded that the molecules can be oriented either very homogeneously or with some scatter in otherwise similar organic nanoaggregates.

A novel method is reported for calculating the nonlinear resonant change in refractive index of a doped saturable medium at the short-pulse excitation. The derived system of equations for energy density and phase of a short pulse propagating in the doped medium allows one to address a rather general case of the resonant index non-linearity caused by the dope's population perturbation (bleaching) effect. As an example, the energy-dependent changes in the refractive index and transmission coefficient of a Cr⁴⁺:YAG crystal under the ns-range (wavelength 1.06 μm) excitation are modeled.

Hugh-order Stokes and anti-Stokes picosecond generation in the visible and near-IR in cubic Tb₃Ga₅O₁₂ garnet crystal was observed for the first time. All scattering laser components were identified and attributed to the SRS-active vibration mode of this crystal.

A novel grating is proposed to produce multi-wavelength output with inscribing phase-shifted fiber Bragg grating (FBG) in polarization-maintaining fiber (PMF). The reflective spectrum of grating is analyzed by a transfer matrix method. The effects of grating parameters on property of the phase-shifted FBG in PMF are discussed. We find that optimistic phase-shifted FBG in PMF with high reflective peaks, narrow bandwidths and multi-wavelength is possible if the grating parameters are properly selected.

Single frequency 1083 nm ytterbium fiber laser was demonstrated by introducing loop mirror filter and polarization controller in linear laser cavity. The loop mirror with unpumped ytterbium fiber as a narrow bandwidth filter discriminated and selected laser longitudinal modes efficiently. Spatial hole burning effect was restrained by adjusting polarization controller appropriately. The laser linewidth was about 2 KHz. Output power up to 14 mW were obtained under the launched pump power of 100 mW at 976 nm, the corresponding optical-optical conversion efficiency was 14%, the slope efficiency was 18%. The measurement of RIN and power stability indicated the stable operation of the laser.

Diverse imaging of point source by a two-dimensional photonic crystal slab with square lattice is studied by the finite-difference time-domain method. Given proper frequencies, there seems to be some special directions like channels guiding the light propagation inside the photonic crystal, along which some images will be created. Although a frequency employed is within the range of resulting negative refraction according the view of [1], the behavior of negative refraction can not been found. It is suggest that except negative refraction there should be multiple mechanisms making point image by two dimension photonic crystal slab.

The comparative behaviour of normal and anomalous averages as functions of momentum or energy, at different temperatures, is analysed for systems with Bose-Einstein condensate. Three qualitatively distinct temperature regions are revealed: The critical region, where the absolute value of the anomalous average, for the main energy range, is much smaller than the normal average. The region of intermediate temperatures, where the absolute values of the anomalous and normal averages are of the same order. And the region of low temperatures, where the absolute value of the anomalous average, for practically all energies, becomes much larger than the normal average. This shows the importance of the anomalous averages for the intermediate and, especially, for low temperatures, where these anomalous averages cannot be neglected.

The solution of the Maxwell-Schrodinger equations describing amplification of backwards matter waves in the process of light scattering from a Bose-Einstein condensate of dilute gas is presented. The results obtained (without the mean field approximation) explain the main features of the effects observed in [1].