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The spectral lines broadening in femtosecond laser plasma generated by the 45 fs Ti:Sa laser pulses on the surface of the water solutions of Ba is investigated. Under the experimental conditions, determined the temperature of femtosecond laser plasma is 3000K.The contribution of the Doppler broadening for spectral lines width is minimal and amounts 0,0022 nm for Ba. The main mechanism of Ba spectral line broadening in experimental conditions is resonance. The resulting values of resonance broadening constitute a0,0349 nm for Ba I (413,24 nm), 0,0563 nm for Ba I (553,54 nm), 0,0241 nm for Ba II(455,41 nm), 0,0437 nm for Ba II (614,17 nm).

The limit of detection for Mg, Mn, Sr, B was experimentally investigated depending on the laser pulse repetition rate in the time resolved femtosecond LIBS. Optical breakdown on the surface of aqueous solutions was generated by the femtosecond Ti:Sa laser with the following parameters: central wavelength - 800 nm, pulse width - 60 fs, pulse energy - 1 mJ, repetition rate 50 Hz, 166 Hz, 250 Hz, 500 Hz, 1000 Hz. The best limit of detection was obtained for the 166 Hz laser repetition rate and for the following elements Mg I (285.2 nm), Mn I (403 nm, 403.3 nm), B I (283.2 nm), Sr I (460.7 nm) are 0.058, 0.025, 1.13, 4.69-3 mg/kg respectively.

The spectral and temporal characteristics of plasma radiation generated by a Ti:Sa femtosecond laser pulses on the surface of Ca aqueous solutions are investigated. Optimum parameters of laser radiation and signal registration are determined to improve the metrological characteristics of time-resolved femtosecond laser induced breakdown spectroscopy.

Specific features of modification of a new photorecording material based on PMMA doped with 2,2-difluoro-4-(9-antracyl)-6-methyl-1,3,2-dioxaborine are studied. The recording of the filament distribution in the studied material occurs at the expense of two-photon photochemical processes. The three-dimensional modification of the material is achieved in the filamentation regime without supercontinuum generation. It is possible to order the volume structure by preliminary photo-modification of the near-surface layer of the material.

Time-resolved laser-induced breakdown spectroscopy (LIBS) has been used as an analytical chemistry technique suitable for water analysis. Optical breakdown on the surface of water solutions was generated by the femtosecond Ti:Sa laser with the following parameters: central wavelength - 800 nm, pulse width - 60 fs, pulse energy - 1 mJ, repetition rate 50 Hz, 166 Hz, 250 Hz, 500 Hz, 1000 Hz. The limit of detection (LOD) for Mg I (285.2 nm), Mn I (403 nm, 403.3 nm), Pb I (283.3 nm), Sr I (460.7 nm) was experimentally investigated depending on the laser pulse repetition rate by the time resolved femtosecond LIBS. The best LODs for Mg I - 0.058 mg/kg, Mn I - 0.025 mg/kg, Pb I - 0.711 mg/kg, Sr I - 4.69 x 10 -3 mg/kg water solutions were obtained for 166 Hz repetition rate.

Experimentally investigated limit of detection Mg, Al, Sr, Pb. depending on the pulse repetition rate femtosecond Ti: Sa laser optical breakdown in aqueous solutions on the surface of the investigated element in the laser pulse duration 60 fs, pulse energy of 1 mJ. The study was conducted for the laser pulse repetition rate of 50 Hz, 150 Hz, 250 Hz. To choose the optimal time delay of registration relative to the laser beam for the following chemicals Na, N, Fe, Ca, Mg, Al, Pb, Mn.

Recently, interest in the study of processes occurring in the optical breakdown on the surface of solid targets associated with the increasing number of practical applications of the laser spark, such as laser induced breakdown spectroscopy and micro-and nanomaterials processing. One of the most important tasks - to reduce the diameter of the focal spot, because the size of the modifications directly related to it. However, it is not the only problem faced by the transition to sub-micron range modifications.

The influence of pulse repetition rate of a femtosecond Ti:Sa laser (800 nm, 45 fs, 0.82 mJ) on intensity of spectral lines at optical breakdown on the surface of CaCl2 water solution is experimentally determined. It is demonstrated that, with increasing pulse repetition rate from 20 to 1000 Hz, the intensity of Ca II (393.3 nm) emission line reduces by 44%, while the plasma continuum remains unchanged within measurement error.

The spectral lines broadening in femtosecond laser plasma generated by the 45 fs Ti:Sa laser pulses on the surface of the water solutions of Ba is investigated. The contribution of the Doppler broadening for spectral lines width is minimal and amounts 0.0022 nm for Ba. The main mechanism of Ba spectral line broadening in experimental conditions is resonance. The resulting values of resonance broadening constitute a 0.0349 nm for Ba I (413.24 nm), 0.0563 nm for Ba I (553.54 nm), 0.0241 nm for Ba II (455.41 nm), 0.0437 nm for Ba II (614.17 nm).

Experimentally determined the influence of energy and pulse repetition rate of the femtosecond Ti: sapphire laser on the intensity of the spectral lines in the optical breakdown on the surface of an aqueous solution of CaCl 2 and aqueous solutions of iron. The time dependence of the intensity of the continuous and line spectra of the plasma was obtained from the laser pulse energy. It is shown that by increasing the laser pulse repetition frequency from 20 Hz to 1000 Hz is observed up to 45% reduction of the emission line intensity Ca II (393.3 nm).

Created three modifications lidar systems based on Ti: sapphire laser with chirped power amplification (elastic scattering lidar, Raman lidar, white light lidar) and derived atmospheric lidar sensing data in a transition zone continent-ocean. Comparisons of the data with the results of conventional lidar based on the use of nanosecond laser pulses are presented. Possibilities and prospects created by femtosecond lidar modifications in the conditions of the transition zone continentocean.

We have evaluated the feasibility of using femtosecond laser-induced breakdown spectroscopy with time-resolved detection of the spectra for determination of trace concentrations of chemical elements in water. The laser plasma was generated on the surface of aqueous solutions by a single pulse from a titanium:sapphire laser (pulse duration 40 fs, pulse repetition frequency up to 1 kHz). We obtained the 3σ limits of detection (LODs) for Al, Ba, Ca, Cu, Fe, K, Mg, Na, Zn in water as 0.19, 0.08, 0.01, 0.78, 3.4, 0.006, 1, 0.0009, 2.5 mg/L respectively.

Spectral and time characteristics of a hydrogen HI 656 nm emission line are experimentally investigated during optical breakdown generated by pulses of the first harmonics of a femtosecond Ti:Sapphire laser on the water surface. The electron density of the generated plasma is estimated.

The influence of the diameter of the beam of a femtosecond Ti:Sapphire laser (800 nm, 40 fs, 0.8 mJ) on the intensity of spectral lines upon optical breakdown on the surface of CaCl2 aqueous solution has been determined experimentally. It is shown that an increase in the laser-beam diameter from 7 to 14 mm on a focusing lens for identical pulse energy increases the intensities of the CaII (393.3 nm) and Hα (656 nm) lines by factors of 3 and 20, respectively. This effect can be used to increase the intensities of emission lines of chemical elements in femtosecond laser-induced breakdown spectroscopy of liquids and, accordingly, improve the sensitivity of this method.