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YVO4:Yb,Er upconversion nanoparticles (UCNPs) are synthesized to study the possibility of using them as nanoprobes to solve biological problems. Aqueous colloidal solutions of UCNPs are injected into the bodies of grape snails. When preparations from animal organs are irradiated with a continuous wave (CW) laser at a wavelength of 980 nm, luminescence is observed in the region of 520–560 nm, due to radiative transitions in Er3+ ions. A comparative analysis of the behavioral activity of animals with injected nanoparticles and control animals with no nanoparticles reveals no signs of toxicity. The nanoparticles are promising as luminescence nanoprobes in biological problems.

Nanoparticles of YVO4 doped with Yb3+ and Er3+ ions, which exhibit upconversion luminescence upon cw laser excitation at 980 nm, are synthesized according to the familiar hydrothermal procedure. Physical and structural features of intermediate products obtained at different technological stages of creating upconversion nanoparticles are established via electron microscopy, Raman spectroscopy, and luminescence microscopy.

Using amplified femtosecond pulses at a wavelength of 1028 nm, the second harmonic is generated at a wavelength of 514 nm by composite polymer films containing D-π-A (push–pull) chromophores with quadratic optical nonlinearity. It is shown that these films are photostable with respect to laser pulses having peak intensities of up to 11.6 GW/cm2. The effective generation of the second harmonic is observed in a wide range of pump beam incidence angles (20°–80°) with a maximum in the vicinity of 60°.

The signal of the ultrafast optical Kerr effect (OKE) in liquids, including toluene C7H8, nitrobenzene C6H5NO2, and acetonitrile C2H3N is analyzed. It is shown that considering the correlation between the orientational and librational responses allows us to determine the rise time of the orientational response associated with the inertial nature of molecular rotations over a time interval of 300–500 fs after the impact of a laser pulse, and to increase the accuracy of determining the form of the Raman spectral density function.

An analysis of the prospects for creating new luminescent molecular photonics materials based on mesogenic lanthanide(III) β-diketonate complexes is presented. We consider vitrified films that combine intense monochromatic luminescence, high optical quality, and complete resistance to UV radiation with the ability to change their photophysical properties (for example, the absorption band width and luminescence intensity) depending on the local structure and under external actions, such as UV radiation and temperature. The problems of control of the photophysical properties of these films and the possibility of their application as working media of high-tech luminescent materials and devices (for example, luminescent sensors of temperature, oxygen, and UV radiation, as well as light-conversion materials) are discussed.

Experiments on recording the ultrafast optical Kerr effect (OKE) in solution of europium(III) β‑diketonate complexes in toluene at a concentration of 10–2 mol/L showed that the total OKE signal is not a superposition of two contributions, one of which is related to the vibrational–rotational dynamics of toluene molecules, while the other is due to the vibrational–rotational dynamics of the europium(III) complexes. This immediately indicates that the europium(III) complexes essentially change the structure of liquid toluene, which is reflected in the character of an orientational response in picosecond range.

The decomposition of the recorded signal of the ultrafast optical Kerr effect (OKE) in benzonitrile into its components corresponding to different molecular contributions is considered. An optical scheme based on two-pulse nonresonant pumping with the registration of a test laser pulse is devised for this purpose.

The use of multiple-pulse laser excitation to control molecular responses that produce the ultrafast optical Kerr effect in order to perform selective spectroscopy of the Raman-active motions of molecules in liquids is discussed. Theoretical analysis and experimental data indicate that multiple-pulse laser excitation is a powerful spectroscopic tool that allows unique information to be obtained about low-frequency molecular dynamics in a liquid.

YVO4:Yb,Er luminescent nanoparticles (NPs) with sizes of 10–700 nm are produced. The use of laser excitation wavelengths of 980 and 257 nm results in the emission of Er3+ ions in the spectral region of 527 and 555 nm. No spectral line of Er3+ ions is recorded at 660 nm, which is indirect evidence of the low efficiency of nonradiative multiphonon intra-ion transitions and the insensitivity of NPs to luminescence quenchers in an aqueous solution.

Results from the nonresonance spectroscopy of CdS/CdSe quantum dots (composites of CdSe–CdS nanoparticles (core–shell)) are presented. The nonlinear optical properties of CdS/CdSe QDs in PMMA are studied with fs pulses at 1053 nm using the transient lens technique. QDs generate rapidly oscillating signals with amplitude rise times of around 200 fs and decay times of around 500 fs, while pure PMMA polymer only generates an oscillating signal whose envelope coincides with its autocorrelation function.

We have fabricated the upconversion nanoparticles (NPs), which are nanocrystallites of 10 nm, doped with Yb3+ and Er3+ ions, prepared through hydrothermal method. Monitoring of their photophysical properties had been realized at different fabrication stages by using electron microscopy and luminescence spectroscopy under photoexcitation of the NPs with the 100 mW laser at 980 nm wavelength. The performed monitoring allows us to observe dramatic changes in the upconversion properties of the NPs during the sequence of the fabrication stages and revealed very strong correlation between the NPs’ upconversion efficiency and their structural specificities.

Using the hydrothermal method, we synthesized water soluble YVO4: Yb, Er nanoparticles with a size less than 10 nm. Nanoparticles exhibit intense luminescence in the green region due to Er3+ ions when excited by laser radiation at a wavelength of 980 nm as a result of the up-conversion process. Bright and stable luminescence also persists in an aqueous solution of nanoparticles. Based on experimental data, it can be argued that the objects obtained are promising in biological applications, as well as up-conversion phosphors.

Bulk SrTiO3 doped by 40 keV Cr+ ions and substrate temperature Timp = 600°C is studied. This sample exhibits supercontinuum generation by amplified femtosecond laser pulses (λ = 800 nm; repetition rate, 3 kHz; pulse duration, 150 fs; pulse energy 4 µJ), recorded by a monochromator with a PMT. The blue edges of the supercontinuum spectra differ, depending on the location of the focused laser beam spot on the sample.

We report on the decomposition of the molecular contribution to the optically heterodyne-detected optical Kerr effect (OHD-OKE) in benzonitrile C6H5CN in the process of double-pulse laser excitation. The pump pulses with linear orthogonal polarizations, controllable intensities and timing enable us to manipulate the amplitudes of various molecular responses due to the fact that the OHD-OKE signal is formed by the superposition of independent third-order responses associated with each pump pulse. We apply this technique to detect the intermolecular response selectively by using an excitation scenario with suppression of orientational and intramolecular responses. A detailed comparative analysis of third-order optical responses indicates strongly that the double-pulse excitation of the OHD-OKE is the useful spectroscopic technique to obtain precise information on the intermolecular spectrum in liquids.

The study of the terbium(III) and gadolinium(III) β-diketonate complexes by photoluminescence spectroscopy reveals considerable changes of the photophysical properties of the complexes under the UV laser irradiation. The measurements show the enhancement of the luminescence intensities in the vitrified transparent film of the terbium(III) complex as well as the gadolinium(III) complex under the 337 nm laser irradiation at room temperature. The irradiated film of the terbium(III) complex restores the initial photophysical properties after heating close to the melting temperature (∼353 K) and cooling. We observe no change of the luminescent properties of the irradiated film for months. These features can be used for the design of new lanthanide-based photostable systems with laser control of the luminescence intensity.

Simultaneous control over the vibrational and rotational molecular responses in ultrafast optical Kerr-effect signals in acetonitrile, toluene, and chloroform at room temperature is achieved by means of non-resonance excitation with two 30-fs orthogonal linearly polarized laser pulses. It is shown that the orientational response of the molecules can be suppressed and their vibrational response isolated by enhanced the delay between the exciting pulses and their relative intensity.

We revealed the effect of the prolonged UV laser irradiation on luminescent behavior of photonic materials based on mesogenic lanthanide(III) β-diketonate complexes by using a novel 3 μm vitrified film of an europium(III) β-diketonate complex. We used the Eu3+ ions to monitor the UV laser-induced photophysical processes in the film. Despite the fact that usually prolonged UV irradiation leads to irreversible photofragmentation of ligands, we had observed no photodecomposition of the complexes after the irradiation of the film with the 337 nm laser for 5 h. The spectroscopic study revealed (i) a 16.5-fold luminescence intensity decrease due to laser-induced changes in inner coordination spheres of the Eu3+ ions and (ii) the main channel of non-radiative energy losses from the Eu3+ ions through the multiphonon relaxation. These features open up new possibilities for designing advanced photonics materials with excellent photostability and luminescent properties controlled during operation.

We have studied picosecond dynamics of photo-induced charge carriers in CdSe/CdS nanoparticles with sizes of 2.0 and 2.9 nm in toluene colloidal solutions using femtosecond up-conversion spectroscopy. The kinetics of nanoparticles luminescence excited by laser pulses of 50 fs duration at 350 nm were observed. The simulation of experimental data showed that electron thermalization occurs within 0.5 ps, while recombination processes have characteristic times of 5 and 20 ns, although these cannot be unequivocally identified using the simplest recombination model with direct transitions and single type of traps. However, a comparative analysis indicates a fundamental difference in the mechanisms responsible for the dynamics of charge carriers in the time interval up to 5 ps after laser excitation, which we associate with different structures of traps in 2.0 and 2.9 nm particles.

Two-pulse control of time-dependent anisotropy in liquid carbon tetrachloride at room temperature is implemented by using femtosecond polarisation spectroscopy. The liquid is excited by a train of two linearly polarised laser pulses, and the state of anisotropy is probed by a weak third pulse with registration of the optical Kerr effect. It is shown that by varying the delay between the exciting pulses and their relative intensity, selection of contributions of individual intramolecular modes into the recorded signal is achieved.

Optical control of coherent intramolecular oscillations in chloroform CHCl3 and dimethyl sulfoxide (CH3)2SO is attained experimentally under normal conditions by means of femtosecond polarization spectroscopy. Nonresonant excitation of the medium is accomplished by a sequence of two linearly polarized laser pulses. The state of the medium is probed by the third pulse via the optical Kerr effect. We show that control over the vibrational dynamics of molecules on a sub-picosecond scale can be achieved by varying the delay between the excitation pulses and their relative intensity.

A novel molecular polarization spectroscopy method of processing the strengthened femtosecond signals, based on the ultrafast optical Kerr effect, is proposed. The processing of the reference chloroform signal by the novel method at a room temperature is demonstrated. It is shown that due to the manipulation by individual molecular motions through the constructive or destructive interference of corresponding wave packets it is possible to determine directly from the experiment such constants of molecular dynamics as the relaxation times of the coherent vibrations (≈1.5 ps) and orientation anisotropy (≈1.2 ps).

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.

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.

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.

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.

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.