Table of contents

One-dimensional Bose gases are considered, interacting either through the hard-core potentials or through the contact delta potentials. Interest in these gases gained momentum because of the recent experimental realization of quasi-one-dimensional Bose gases in traps with tightly confined radial motion, achieving the Tonks-Girardeau (TG) regime of strongly interacting atoms. For such gases the Fermi-Bose mapping of wavefunctions is applicable. The aim of the present communication is to give a brief survey of the problem and to demonstrate the generality of this mapping by emphasizing that: (i) It is valid for nonequilibrium wavefunctions, described by the time-dependent Schrödinger equation, not merely for stationary wavefunctions. (ii) It gives the whole spectrum of all excited states, not merely the ground state. (iii) It applies to the Lieb-Liniger gas with the contact interaction, not merely to the TG gas of impenetrable bosons.

The third near infrared stimulated-emission spectral range of Nd:YAG ceramics at room temperature has been demonstrated. For the ⁴F_3/2 → ⁴I_9/2 transition emitting at 946 nm 1.35 W laser output have been achieved under 808 nm laser diode pumping at more than 20% efficiency similar as for crystalline material.

Near-diffraction-limited longitudinal multimode self-Q-switched microchip Cr,Yb:YAG laser is obtained by using of a laser diode as a pump source at room temperature without cooling Cr,Yb:YAG sample. The output Q-switched traces are very stable, and the slope efficiency is as high as 18.5%. Laser pulses with 23.5-μJ pulse energy and 440-ps pulse duration were achieved which results in over 53 kW peak power at repetition rate of 6.6 kHz. The effect of the absorbed pump power on the laser characteristics and laser spectrum are addressed in details. The number of the longitudinal laser modes increases with the absorbed pump power.

A laser incident on an overdense plasma, generates a space charge wave at second harmonic (2ω). The amplitude of the generated wave is resonantly enhanced at 2ω=ω_p, leading to substantial reduction in the reflectivity of the plasma. The generated plasma wave can accelerate the electrons to few keV of energies.

The Raman gain coefficient of a barium tungstate crystal was measured in the 532 nm to 1064 nm spectral region. The experimentally obtained data were fitted with the empirical equation, which takes into account the resonance electronic transitions.

Theoretical investigation is carried out of the heating of a small solid (metal) ellipsoidal particle in a liquid or gaseous medium by laser radiation pulses. The solutions are obtained for quasi-stationary distributions of temperature inside and around of a particle and conductive heat transfer between the particle and the surrounding medium with allowance for the temperature dependence of the transfer coefficients. The heating of ellipsoidal nanoparticle in medium on exposure to laser radiation pulse and following cooling is considered on the base of analytical solutions. The time dependencies of particle temperature are obtained. The estimation of absorbed and scattered laser radiation energies by gold ellipsoidal nanoparticles, their maximal temperatures and comparison with experimental data is made.

The Coulomb-repulsion compensation of classical nonrelativistic hydrogen ions in the beam in crossover in the presence of a strong pulsed laser field with an intensity of about 10¹⁵ W/cm² is theoretically studied. It is demonstrated that the average effective interaction force can fundamentally differ from the Coulomb law.

The effect of doped-fiber's spooling on performance of short wavelength band erbium-doped fiber amplifier (S-band EDFA) is demonstrated. Changing the spooling diameter resulted in a variation of gain and noise figure characteristics of this amplifier. The optimum spooling diameter is obtained in the range from 5 to 7 cm. Beyond this range, an inevitable degradation of gain and noise figure characteristics is observed due to the changes of phase matching wavelength. Therefore, maintaining the optimum spooling diameter is the important issue for the S-band EDFA.

The crystalline lens is a transparent biological material, and a complex inhomogeneous optical element in the vision system of mammals. It is a fiber cell structures [1]. Approximately 90% of the fiber cells composition are proteins responsible for the high refractive index of the lenses. This paper presents Raman spectroscopy as a tool for identification of the proteins and further diagnostic of disease in the lenses. Would all mammal lenses be made of the same proteins? This is the question motivating this work. Raman spectroscopy is a rapid and non-destructive optical method for providing chemical information on molecular structures [2], and has been successfully applied to a variety of biological systems [2,3]. Our aim here is to investigate the protein average distribution in the lenses of distinct mammals by following main differences in the Raman spectral signature. The Raman signatures of healthy crystalline lenses from canine, mouse, pig, rabbit and horse were characterized in vitro. The results indicate that there are no substantial differences at all animals studied.