A. Yu. Mayor

The influence of laser pulse repetition rate on the intensity of spectral lines in femtosecond laser-induced breakdown spectroscopy of a liquid

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.

Nonlinear optical properties of biomineral and biomimetical nanocomposite structures

The transmission of laser femtosecond pulses by spicules of marine glass sponges and monolithic amorphous nanocomposite silica biomaterials synthesized on the basis of natural polysaccharides has been experimentally investigated. The strong non-linear optical properties of these biominerals have been revealed in spectral characteristics of transmitted ultra-short pulses (USP). Comparative analysis of the transmission spectra of USP reveals that spicules exhibit much stronger non-linear optical properties than quartz optical fibers. Recently new monolithic nanocomposite silica biomaterials were synthesized on the basis of various natural polysaccharides and completely water-soluble Si-precursor. The shape of transmitted spectrums through both spicules and new nanocomposite biomaterials demonstrates major changes indicating the broadening with formation markedly strong anti-Stokes component in the output spectrum with generation of supercontinuum spectra. The carried out studies have showed that the nature combination of spongin protein with silicon dioxide extracted from seawater by silicatein protein in glass sponge spicules and monolithic nanocomposite silica biomaterials are biological and biomimetical nanocomposite materials with unique optical properties.

Results of an integrated aerosol experiment in the continentocean transition zone (primorye and the Sea of Japan). Part 2. Analysis of spatiotemporal variations of aerosol characteristics according to satellite data and lidar measurements

In the paper, we discuss the results of the study of the spatiotemporal aerosol optical depth (AOD) variations in the “continent-ocean” transition zone, performed in spring 2009 in Primorye and in the Sea of Japan with the use of satellite and ground-based AOD measurements. Also, the results of a joint analysis of lidar atmospheric sensing data, back trajectory analysis of air mass transport, and satellite monitoring of the state of the atmosphere of the studied region are given.

Nonlinear optical properties and supercontinuum spectrum of titania-modified carbon quantum dots

We have studied the nonlinear optical properties and supercontinuum spectrum of solutions of carbon quantum dots prepared by a hydrothermal process from chitin and then coated with titania. The titania coating has been shown to have an activating effect on the carbon quantum dots, enhancing supercontinuum generation in the blue-violet spectral region and enabling their nonlinear optical characteristics to be varied.

Complex monitoring of the state of sea water basins by optical methods. Part 1. The concept of constructing the multilevel measurement systems for ecological monitoring of coastal water basins

We begin a series of works devoted to the creation of technical means and methods for a rapid and complex monitoring of the state of sea water basins by optical methods. The feasibility of multilevel measurement systems for the ecological monitoring of coastal water basins is demonstrated. We present preliminary results of monitoring of spills formed by organic films of different types of pollutants; the monitoring was performed by means of lidar diagnostics of the water surface with the help of stationary coastal video surveillance systems. The application of submerged fluorometric systems for real-time monitoring of sea waters is shown. The effectiveness of the combined use of these systems for monitoring coastal water basins is discussed.

Results of an integrated aerosol experiment in the continent-ocean transition zone (Primorye and the Sea of Japan); Part 1: Variations of atmospheric aerosol optical depth and vertical profiles

We discuss the results of an integrated aerosol experiment, performed in spring 2009 simultaneously in two regions: near Ussuriysk and in the Sea of Japan onboard the Nadezhda training boat. For the measurements of aerosol optical depth (AOD) and moisture content of the atmosphere, we used multiwavelength sun photometers operating in the wavelength range 0.34–2.14 μm. The measurements of the vertical profiles of aerosol characteristics were made using two types of lidars: a lidar based on a three-frequency (1.064, 0.532, and 0.355 μm) Big Sky Laser CFR 200 in Primorye and a one-frequency laser based on the second harmonic of the Nd:YAG (0.532 μm) laser onboard the sailing vessel. It was shown that the springtime atmosphere in the Far East region has two times larger aerosol turbidity in comparison with other (maritime and continental) midlatitude regions. Average values of the atmospheric AOD in the region of 0.5 μm were 0.46 in Primorye and 0.35 in the Sea of Japan. The elevated atmospheric turbidity is caused by continental aerosol of different types (smoke, anthropogenic, and dust) blown off the neighboring regions. We present the characteristic vertical profiles of aerosol-molecular scattering for the cases of advection of air masses from arid regions of Southeastern Asia and the boreal zone of Siberia. A relation is demonstrated between the dust activity in the Taklamakan Desert and light scattering characteristics of aerosol layers in tropopause region.

Dynamics of the structure of multiple filamentation domain of laser pulses in glass

The results of experiments on the study of spatial characteristics of the multiple filamentation domain of GW Ti:Sapphire laser pulses in glass are presented. The dependences of the coordinates of the beginning, end, and diameter of the multiple filamentation domain (MFD) vs the laser pulse energy are derived. It is found that when the average intensity in the beam attains certain values, MFD is formed near the illuminated side of the glass sample. When the beam intensity attains a threshold, the secondary MFD is formed; its spatial characteristics depend on the pulse-periodic irradiation exposure time. The diameter of the secondary MFD and coordinates of its beginning depend on the exposure time. The spatial characteristics of the primary MFD were independent of the exposure time during the experiments.

Laser spectroscopy methods in the development of laser sensor elements for underwater robotics

Laser technologies that are used for the development of sensor elements for Remotely Operated Vehicles (ROVs) are presented, as well as the latest developments in underwater robotics where laser spectroscopy methods are applied to environmental monitoring. A submersible laser spectrometer unit intended for studying Raman scattering and laser-induced fluorescence (LIF) spectra is presented. The spectrometer was developed as an element of an ROV sensor system for remote detection and measurements of organic matter concentrations in sea water and underwater objects. The results of environmental tests of the submersible LIF spectrometer in various marine areas, including the Arctic, are described.

Multiple filamentation of collimated Ti:Sapphire laser beams in water

The results of experimental studies of femtosecond laser pulse filamentation in water are described. The dependencies of the number of filaments, spectrum width, distance of nonlinear focusing, and diameter of filamentation zone on the laser pulse power are measured. Existence of a segment on the scale of relative power is marked out, where the number of filaments increases dramatically.

Complex monitoring of the state of sea water basins by optical methods: part 4. Fiber optic system for measurements of the phytoplankton concentration

Engineering tools for the real time monitoring of phytoplankton by the fluorescence method in coastal waters are considered. Preliminary results of the monitoring using a submersible fluorimetric system for the real time measurements are given. A possibility of using fiber optic submersible and pumped systems for integrated monitoring of coastal waters is discussed.