Marina S. Yavtushenko

Amplification of frequency-modulated soliton-like pulses in inhomogeneous optical waveguides with normal dispersion

The possibility of effective amplification of self-similar frequency-modulated pulses (FMPs) in longitudinally inhomogeneous active optical waveguides is studied. Peculiarities of the dynamics of parabolic pulses with a constant frequency modulation rate are considered. An optimal profile of variation of the group velocity dispersion was obtained in correspondence with optimal amplification of a similariton-like pulse. The use of FMPs in amplifying and longitudinally inhomogeneous optical waveguides with a correspondingly matched profile of normal dispersion of group velocities is shown to be capable of providing for an amplification of subpicosecond pulses up to energies above 1 nJ.

Optical amplifier with tailored dispersion for energy scaling of similaritons

We propose an optical amplifier composed of fibers with varying normal group velocity dispersion (GVD) for picosecond pulse amplification. The analytical analysis defines the optimal axial distribution of dispersion that results in shaping of the parabolic pulses with controllable chirp. The proposed cascaded all-fiber pulse amplifier employs fiber gain segments with exponential increase of normal dispersion separated by the passive fiber sections with decreasing normal GVD. The cascaded amplifier allows us to prevent an excessive broadening of the pulse spectrum and, therefore, offers an attractive potential for energy scaling of similariton pulses.

Dynamics of a Wave Packet of Whispering-Gallery-Mode Type in an Optical Waveguide in the Presence of a Traveling Refractive-Index Wave

It is demonstrated that strong ultrafast modulation of a tunneling wave packet of the whispering-gallery-mode type can be implemented in a cylindrical optical waveguide exhibiting spatiotemporal inhomogeneity induced by a travelling refractive-index wave. The corresponding optical waveguides can be used for efficient generation of picosecond and subpicosecond laser pulses.

Cascade scheme of FM pulse amplification in length-inhomogeneous active waveguides with normal dispersion

We propose a new all-fiber cascade picosecond pulse amplification scheme based on optical fibers with varying normal group velocity dispersion (GVD). Amplification is performed in the fiber sections with exponential growth of the normal dispersion. Amplification sections are altered by the sections of passive fibers with the decreasing normal GVD. The pulse chirp in dispersion decreasing fibers can be adjusted by the increment of dispersion variation which would allow to control the spectral bandwidth of the pulse to keep it within an amplification band.

Quarter-wave splitter based on heterogeneous composite with prolate silver nanoparticles

The optical properties of an ultra-thin composite slab with uniformly oriented silver nanoparticles are investigated. It is shown that anisotropic plasmonic resonances in nanoparticles lead to strong polarization-dependent reflectance and transmittance in the visible region of light.

Effects of femtosecond laser radiation on blood cell suspensions

In the present work the effects of high-power femtosecond laser irradiation on a functional condition of red blood cells and neutrophils in vitro have been investigated. The data on parameters of the lipid peroxidation - antioxidants system, hemoglobin level and rigidity of red blood cell membranes testify destabilization of the membranes under the influence of the given laser. The study of phagocytic activity, anaerobic and aerobic metabolism of neutrophils, and rigidity of their membranes allows to suppose the dose-dependent effect to be stimulating.

Parabolic pulse generation in the nonlinear nonuniform fibre cascade

A method to carry out the compression of parabolic pulse in the nonuniform fibre cascade was proposed. The periodic modulation of the dispersion along the fibre length can be used to control subpicosecond pulses in time and frequency domains. Good agreement between simulations and experimental data takes place.

Chirped pulse shaping via fiber dispersion modulation

A single-mode fiber with a linear or sinusoidal variation in the group-velocity dispersion is designed and fabricated. The nonreciprocal effects and pulse compression due to the longitudinal oscillations of the fiber dispersion are experimentally demonstrated. The periodic modulation of the dispersion can be used to control precisely the pulse dynamics.