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The possibility to mechanize at room temperature a logical function of bit-to-bit parallel multiplication for optical echo-processor based on the third-order nonlinear optical response of a resonant medium is experimentally studied. The polyvinilbutural film doped with phthalocyanine dye was used as an operating medium in our experiments. The time needed to realize the logical operation, the result of which is presented in the spectrum of the nonlinear optical response of the medium after action of the two spectrally coded pumping pulses, is less than 1 ps. The values of a homogeneous broadening of S0 – S1 line Γhom = 89 cm-1 and Γhom = 44 cm-1 are established at T = 300 K and T = 77 K respectively. The laser excitation parameters needed for effective operating of optical processor are defined. The maximum word length achievable under current experimental conditions is estimated.

An analysis of the absorption and luminescence spectra and luminescence kinetics showed that in the Eu(DK)3bpy17-17 mesogenic adduct, 5,5′-diheptadecyl-2,2′-bipyridine (bpy17-17) took an active part in the energy transfer to the Eu3+ ion. The interligand energy transfer from β-diketonate (DK) ligands was the major mechanism of excitation of bpy17-17. Importantly, the interligand excitation complex considerably decreased radiation losses during the energy transfer from the absorbing DK ligands to the emitting level of Eu3+.

This paper presents the results of our study of molecular librations in liquid ortho-dichlorobenzene (C6H4Cl2) and benzonitrile (C6H5CN) at room temperature. We used femtosecond polarization with recording of the optical Kerr effect (OKE). To analyze the libration response, we divided the total OKE signal into the constituent vibrational and rotational responses. Modeling the libration response, we determined the form of the distribution function of libration frequencies and performed qualitative analysis of the peculiarities of the local potentials of molecules.

The absorption and emission spectra of a liquid-crystalline melt prepared on the basis of a synthesized mesogenic europium (III) adduct are studied in the temperature range from 77 to 348 K. The main channels and rate constants of intramolecular energy transfer from ligands to Eu (III) ions are determined from the absorption and luminescence spectra and luminescence kinetics of the sample under study. It is shown that the liquid-crystalline melt of the europium (III) adduct has a high photostability and an intense luminescence in the temperature range from 77 to 300 K, which allows one to consider it as a promising material for optoelectronic devices. Above room temperature, the relaxation time of the 5 D 0 level of Eu (III) ions sharply shortens. An analysis of the kinetics of the luminescence corresponding to the 5 D 0 → 7 F 2 transition shows that the relaxation of the 5 D 0 level in the temperature range from 300 to 348 K occurs through a charge-transfer state.

The ultrafast optical Kerr effect observed in liquids upon two-pulse laser excitation is studied theoretically. It is shown that a Raman echo on librational frequencies (librational echo) can be excited in liquid. The librational echo has the following features: its shape and amplitude strongly depend on the local inhomogeneity of a medium and the form of local potentials; and the echo signal can be separated into the contributions of the phase and irreversible relaxation of coherent molecular librations. These properties of the librational echo can be used for studying the specific features of the local structure of liquids by the method of selective subpicosecond spectroscopy of molecular librations.

The control of the anisotropy of the orientation of molecules in pure 1,2-dichlorobenzene, C6H4Cl2 at room temperature is demonstrated experimentally. To accomplish the optical control, the medium is exposed to non-resonant excitation with two successive linearly polarized laser pulses with a duration of 60 fs. The state of transient anisotropy is probed with the third pulse by detecting the ultrafast optical Kerr effect via optical heterodyne detection and synchronous demodulation. It is shown that variations in the two parameters, the delay time between two pump pulses, and the angle between the polarization directions of the pump pulses ensure the control of the anisotropy of the orientation of molecules in the subpicosecond region.

The parameters of the femtosecond vibration—rotation molecular dynamics of liquid acetonitrile CH3CN, trimethylacetonitrile (CH3)3CCN, propionitrile CH3CH2CN, fluoroform CHF3, and chloroform CHCl3 are found by analysing the ultrafast optical Kerr effect. The influence of the molecular structure on the features of rotational (diffusion and libration) motions is studied. It is shown that the distribution of libration frequencies is described by the Maxwell distribution.

© 2015 Astro Ltd. We propose and analyze theoretically the implementation of two pump pulses with orthogonal linear polarization for the separate measurement of an interaction induced response in liquids through the optically-heterodyne-detected optical-Kerr-effect. The key parameters controlling the specificity of the double-pulse excitation scenarios are the pulse duration, the delay between pulses and the relation between the pump pulses amplitudes. We use acetonitrile as an example to model the fifth-order optical response and consider some principles of the scenarios construction. We show that it is possible to adjust the excitation scenario in such a way that the intramolecular and orientational responses are removed from the detected signal. The theoretical analysis reveals that the double-pulse excitation technique can be useful for the selective spectroscopy of the interaction induced responses of the molecules in liquid.

We report transient refractive index change in semiconductor nanoparticles dispersed in polymethylmethacrylate matrix via pump-probe experiment. At lower pump intensities the detected signal consists of the pulse autocorrelation-shaped part and another part delayed by 300 fs. The latter’s relative intensity depends on the pump level. However in CdS monocrystal the detected signal was found to lack this second feature completely.

We report the non-resonant excitation and probing of the nonlinear refractive index change in bulk semiconductors and semiconductor quantum dots through degenerate transient lens spectroscopy. The signal oscillates at the center laser field frequency, and the envelope of the former in quantum dots is distinctly different from the one in bulk sample. We discuss the applicability of this technique for polarization state probing in semiconductor media with femtosecond temporal resolution.

Nanoparticles of CdS were isolated by the treatment of thereaction mixture followed by the precipitation of CdS ina centrifuge, and the precipitate was washed with ether.Nanoparticles of CdS in pyridine were mixed in an ultrasonic stirrer with poly(methyl methacrylate) (PMMA) inan amount of 7% of the polymer weight. Then the suspension obtained was poured on a quartz support and dried at60 °C. The resultant sample was a film 0.3 mm thick. Theabsorption spectrum of the nanocomposite СdS—PMMAexhibits a shift to the blue region compared to that ofa single crystal of CdS. This shift is due to the quantumdimensional effect characteristic of nanoparticles of semiconductor crystals.

Conditions for implementing room temperature femtosecond echo-processing in a phtalocyanine-doped polyvinylbutyral film were studied. A logical operation of bit-by-bit multiplication on the basis of the nonlinear third-order optical response (primary photon echo) of the medium was performed in a time of less than 1 ps.

The results of the femtosecond four-wave mixing measurements performed on the CdS crystal at room temperature are reported. The dephasing time Td = 180 fs was obtained. The anti-Stokes shift of the primary photon echo spectrum with respect to the excitation spectrum was observed. The some peculiarities of the coherent responses decay curves indicate that this optical dephasing is due to the exciton-exciton interaction. The stimulated photon echo decay curves appear to have a fast decay component (the time constant of approximately 4.5 ps) in case the energy of exciting pulses exceeds the threshold value of 0.4 μJ.

We report the first experiment results on selective spectroscopy of librational response in ortho-dichlorobenzene at room temperature. By optimization of the controlling parameters we have achieved the suppression of the Raman-active vibrational and orientational responses. We have used the two-pulse excitation scheme. The controlling parameters were pulse duration, intensity and delay between two pump pulses.

We demonstrate experimentally the laser control of the nonstationary anisotropy of polarizability in a pure liquid of demethilformamide (CH3)2NCOH at room temperature. The experiment is based on the nonresonant medium excitation by a sequence of two linear polarized laser pulses with the duration of 60 fs. The state of medium is probed by the third weak laser pulse with the registration of the ultrafast optical Kerr effect. We obtained that by using two parameters (the delay between the pump pulses and the angle between the directions of the linear polarization of two pump pulses) the molecular orientational anisotropy in liquid is controlled in the subpicosecond time scale.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The laser non-resonant excitation based on the (2?????2) sequence of the two pairs of the pump pulses with orthogonal linear polarizations is proposed and theoretically considered for the control of the vibrational responses without or with the low amplitude of the rotational responses in a liquid. As an example, we model the optical molecular responses resulting in the optical Kerr effect transients in ortho-dichlorobenzene. Theoretical analysis shows the high efficiency of the (2?????2) excitation scenarios for the various manipulations of the molecular responses.

Optical Kerr effect in the spectrum of chloroform is investigated by the method of two- pulse pumping. Here it's shown that during one-pulse pumping hyperpolarizability response, libration, the orientation response and the response of the intramolecular vibrations take place. Also we have achieved the suppression of intramolecular vibrations by two-pulse pumping with corresponding intensity and time delay.

A variant of the flashlamp for NIF was developed on the base of the experience of manufacture and application of high- power flashlamps in Russia. Features of flashlamp design as well as first test results of the experimental samples are presented.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

With the aim of improving output parameters and operating characteristics of ArF excimer laser intended forsubmicrolithography intracavity Fabry-Perot etalons able to effectively narrow and tune laser radiation were developedand tested. Used in an YYE 1702 compact excimer laser two innovative etalons permitted to achieve maximum outputenergy of 5 mJat 193,3 nrn. bandwidth of 20 pm at 0.5 level for S ns pulse duration. 20 x 5 mm output beam aperture,100 Hz pulse repetition rate. The dispersive resonator shovs high energy efficiency.2. INTRODUCTIONUv excimer lasers are finding increasing use in different fields of science and technology. In particular, at the present time extensive investigations are being conductive to determine potentials of their use in subniicron photolitography for VLSI production. Laser unique features -short avelenght and high spectral brightness of radiation permit to increase resolution and productivity of photolithograph setups. From this point of view excimer ArF laser as ahigh-energy short-wave LJV laser generating at 193 nm is considered to be the most attractive Photolithography imposesstringent requirements for lasers in terms of their energy. spectral and cogerent characteristics as veIl operational ones.

The optical control of the molecular motions in chloroform CHCl3 at room temperature through the non-resonant excitation was enhanced by means of the double-pulse pump-probe technique. When the separation time of the pump pulses and their relative intensity were varied, the amplification or the cancellation of the coherent vibrations of the molecules was achieved. The molecular responses were detected by the time-resolved optically heterodyne-detected optical-Kerr-effect technique.

First time the possibility to use unstable telescopic resonator with Fabry-Perot etalon as a selective spectral element in excimer KrF laser to reduce the beam divergence and narrow linewidth of laser radiation is demonstrated. The efficiency of the new resonator was demonstrated on serial laser 9J114-'94, and radiation with the following parameters was received — output energy 20 mJ, spectrum width 15 pm, energy divergence less or equal O.18x0.30 mrad. The spectral brightness of the laser radiation was increased more than for order of value in comparison with the use of a conventional selective flat resonator, and achieved 2.5 * io J/cm2 * sr * nm. Further improvement of laser characteristics due to optimization of proposed optical resonator scheme parameters is possible.

Efficient spectral narrowing, tuning, and stabilization devices characterized by improved energy efficiency and operating parameters have been constructed. The devices are used with KrF lasers intended for submicron lithography. Up to 5 pm spectral line narrowing is provided by two Fabry Perot etalons with thoroughly optimized parameters. They permit us to achieve unprecedented spectral narrowing energy efficiency of 50%. A special device based on a passively stabilized reference Fabry-Perot etalon is used for laser wavelength stabilization within 1 pm. A unique optical scheme of interference pattern formation is realized in the device; the laser wavelength is controlled by spatial location of fringes. The device also features precision wavelength tuning (approximately 0.1 pm), better resistance to electromagnetic noise, and higher operating characteristics.