Vitaly N. Krylov

Hologram recording in DuPont photopolymer films by use of pulse exposure

Reflection hologram recording in DuPont HRF-800X071-20 photopolymer films has been demonstrated by use of pulsed laser exposure with pulse lengths of 25 ns. An expected weak reflectance of the recorded mirror holograms could be significantly increased by preillumination. Although pulsed preillumination enhanced only the reflectance, continuous incoherent preillumination significantly increased both the diffraction efficiency (which reached ~80%) and the sensitivity (which reached an increase of ~100 times, thus approaching the sensitivity of cw recording). The results are compared with those for hologram recordings obtained with cw exposure under the same processing conditions. Spectral absorbance curves of recorded holograms are presented, and possible mechanisms of hologram formation are discussed.

Noncollinear parametric generation in LiIO 3 and β-barium borate by frequency-doubled femtosecond Ti:sapphire laser pulses

In LiIO(3) and BBO crystals the wave-matching conditions for femtosecond noncollinear parametric light generation at lambda = 390 nm pumping wavelength are investigated. In the LiIO(3) crystal simultaneous phase- and group-velocity-matching angles are determined. Parametric generation occurred at 0.45-2.9-mu;m wavelengths by pumping with the second harmonic of 150-fs Ti:sapphire laser pulses and is in qualitative agreement with calculated directions in both crystals.

Noncollinear parametric generation and amplification in LiIO3 and Beta-barium borate by frequency-doubled femtosecond Ti:sapphire laser pulses

In LilO3 and BBO crystals noncollinear parametric generation with tuning range 0.45 - 2.9 micrometers is investigated by pumping with the second harmonic of 150 fs Ti:sapphire laser pulses. In LilO3 propagation angles simultaneous phase- and group-velocity-matching are determined. Noncollinear parametric amplification with the wavelength tunability from 0.6 to 1.2 micrometers is demonstrated.

Second, third, and fourth harmonic generation of amplified femtosecond Ti:sapphire laser pulses

We studied both experimentally and theoretically, the conversion efficiency of 150-fs-duration Ti:sapphire laser pulses to the second, third and fourth harmonic. The laser pulses at the wavelength of 780 nm have a spectral width of 10 nm and were amplified to 0.8 mJ energy in a regenerative amplifier. With a repetition rate of 1 kHz intensity of up to 150 GW/cm2 could be reached by focusing the beam with a lens. KDP, BBO and LilO3 crystals of different length were used for the conversion process. The experimentally observed conversion efficiency to the second, third and fourth harmonic does not exceed 50%, 15% and 8%, correspondingly. It is shown theoretically that one possible process limiting the conversion efficiency of the femtosecond pulses at low as well as high intensity is the modulation of the phase of the fundamental wave.

Femtosecond IR supercontinuum generation in condensed media

We report experimental and theoretical investigation of supercontinuum generation in broad spectral range from 500 nm to 2500 nm induced in water and bulk fused silica by 1mJ 150-fs pulses at 780 nm excitation wavelength. We find that experiments may be modeled theoretically by considering Raman- and Kerr-type nonlinearities such as transient stimulated Raman scattering, parametric four-photon mixing, self-phase modulation and cross-phase modulation.

Raman-scattering-based Na guide star generating and receiving laser system

The concept for a new approach to generating and receiving optical system for sodium guide star excitation based on solid-state laser technology and the stimulated Raman scattering/amplification in compressed gases is presented. Requirements to laser system for laser guide star generation are analyzed. The most promising SRS media are chosen.

Stimulated Raman scattering by frequency-doubled 1 kHz amplified femtosecond Ti:Sapphire laser in H2, D2, HD and CH4 gases

We present results on stimulated Raman scattering in H2, D2, HD and CH4 excited by 200 fs-duration 1 kHz repetition rate and 0.6 mW average power Ti:sapphire laser (780 nm) and 0.2 W average power second harmonic (390 nm) pulses with linear and circular polarization. Spectral and temporal measurements of the vibrational and rotational components at Stokes- and anti-Stokes frequencies in the wavelength range 289 - 1154 nm are reported. We observed 2.5 times shortening of the vibrational Stokes component pulses in H2 and D2 exited by 350 fs-duration second harmonic pulses.

Vibrational and rotational stimulated Raman scattering in hydrogen by 1-kHz amplified femtosecond Ti:sapphire laser

We present the results on stimulated Raman scattering in hydrogen excited by 200 fs-duration 1 kHz repetition rate and 0.6 mW average power Ti:sapphire laser (780 nm) and 0.2 W average power second harmonic (390 nm) pulses with linear and circuit polarization. We report on the spectral and temporal measurements of the various generated vibrational and rotational components at Stokes- and anti-Stokes frequencies in the wavelength range 289 - 1154 nm. At optimal conditions at 390 nm pump wavelength the SRS signal of 30 mW average power was obtained at the first (465 nm) and the second (577 nm) vibrational Stokes. The shortest measured duration of the vibrational Stokes components was by 3 times less than the duration of the pump pulses.

Sensitivity of silver-halide emulsions at exposure durations 10 2 -10 -13 seconds

The sensitivity of a fine-grained silver halide VRP photoplates exposed by laser radiation over a wide range of durations (102 - 10-3 sec) is studied. The drastic deviation of sensitivity in the time range from 10-9 sec to 10-13 sec is found and discussed.

Modern holographic studio

The results of work of the holographic studio of the State Optical Institute which is equipped with multicolor pulsed lasers and continuous wave lasers as well as appropriate photomaterials are presented. In this studio any technique of recording can be realized in pratice for various objects including alive. Maximum size of monochrome holograms is 1. 2 x 0. 8 m and color holograms is 60x40 cm 1. INTRODtXT ION At present the display ho lography is the most mass appl icat ion of ho lographic methods popul ar among the populat ion. Due to the permanent interest of holographers to production of display holograms the methods of their recording are now brought to perfection and quality of holograms is of such a level that an observer in a number of cases prefers the holographic image to the original. Such progress in display holography allows transition from technical problems of image quality improvement to problems of artistic representation of objects and forms of the world around. Organization of holographic studios is one of the ways for realization of such a transition. These holographic studios provide the possibility of systematic recording of a wide range of objects and compositions including peopl. nd animals. The first steps in this direction were made in the USSR and USA in 19671970 now the holographic studios exist also in other countries. Broad prospects in realization of artistic