O. I. Kuchinskaya

Interaction of femtosecond pulses of a two-harmonic Ti:Sapphire laser with liquid media

The interaction of ultrashort laser pulses having wavelengths of 400 and 800 nm with liquid media, including organic solutions, has been experimentally studied. It is shown that transparent drops evaporate and boil (with partial mass ejection in the form of vapor and liquid fragments) in the field of ultrashort light pulse. A large-scale change in the spectrum of laser pulse during its interaction with a water particle is revealed. This change is caused by self-modulation of the light phase due to the Kerr optical nonlinearity of liquid and the formation of plasma. Filamentation in continuous liquid media is analyzed; specifically, the dependences of the number of filaments, the lasing spectrum width, the nonlinear-focusing distance, and the filamentation region diameter on the laser pulse power are measured. It is noted that there is a range of relative powers where the number of filaments very rapidly increases. It is shown that the spectral broadening at filamentation, observed for fixed pulse energy with a change in pulse width, overlaps the entire visible spectral range. This circumstance makes it possible to obtain width-tunable pulses and use them, e.g., in optoacoustic diagnostics of media.

Multiple Filamentation Various Diameters Laser Beams at a Atmospheric Path

Results of experiments on controlling the position and length of the filamentation zone of femtosecond laser pulses in atmospheric path length 150 m using different initial spatial focusing and defocusing. The obtained distribution of filaments along the filamentation domain, measured dependence the length of the filamentation zone of the numerical aperture of the beam, its initial radius and pulse power. Registered emission spectra of the illumination targets of various materials, placed in the filamentation zone remote from the radiation source.

Postfilamentation channels of terawatt pulses Ti: sapphire-laser by propagation on 150 - meter path

The results of experimental studies of postfilamentation channels controlled by the track length of 150 meters for collimated beams of different diameters. It is shown that the divergence of the laser beam after the filamentation area is much greater than the divergence postfilamentation channels. It is shown that at distances from the end of the field filamentation, significantly exceeding the length of the field filamentation, postfilamentation channels contain sufficient intensity to generate multiple filamentation in the optical elements and enables us to provide a functional effect on the optical elements of the matrix.

Macroscopic model of formation of the domain of multiple filamentation in glass and water

The results of natural experiments of the propagation of powerful femtosecond laser radiation in glass and water, accompanied by multiple filamentation, and the results of numerical simulation of the process are presented. Based on the diffusive equations for density of the number of filament estimates of the positions of maxima in the number of filaments were obtained. Sufficient criterion of macroscopic refocusing for density of the number of filaments was established.

Filamentation of collimated Ti:sapphire-laser pulses in the glass

The results of experiments to study the spatial characteristics of multiple filamentation gigawatt laser pulses in the glass are presented. It is shown that with increasing pulse power multiple filamentation region increases in length and diameter, the distribution of filaments within the region has a maximum value when the power > 105 Pcr area filamentation takes the form of a hollow cone, the apex directed to the source of the laser radiation.

Multiple filamentation of laser beams with different diameters in the air at a 150-meter path

Results of experiments on controlling the position and length of the filamentation zone of femtosecond laser pulses in atmospheric path length 150 m using different initial spatial focusing and defocusing. The obtained distribution of filaments along the filamentation zone, measured dependence the length of the filamentation zone of the numerical aperture of the beam, its initial radius and pulse power.

Multiple filamentation of laser pulses in the glass

The results of experiments to study the spatial characteristics of multiple filamentation gigawatt laser pulses in the glass are presented. It is shown that with increasing pulse power multiple filamentation region increases in length and diameter, the distribution of filaments within the region has a maximum value when the power > 105 Pcr area filamentation takes the form of a hollow cone, the apex directed to the source of the laser radiation.

Multiple filamentation of laser beams with different diameters in the air at a 100-meter path

Results of experiments on controlling the position and length of the filamentation zone of femtosecond laser pulses in atmospheric path length 110 m using different initial spatial focusing and defocusing. The obtained distribution of filaments along the filamentation zone, measured dependence the length of the filamentation zone of the numerical aperture of the beam, its initial radius and pulse power.

Filamentation of focused and collimated laser beams in liquids

Experimental results of investigations into the transformation of the spectral and spatial characteristics of femtosecond collimated and focused Ti:Sapphire-laser beams with wavelengths of 800 and 400 nm upon filamentation in continuous liquid media are presented. It is shown that broadening of the laser pulse spectrum due to phase self-modulation in the medium with a cubic nonlinearity depends on the pulse power and beam diameter. Dependences of the number of filaments, width of laser radiation spectrum, nonlinear focusing distance, and diameter of the filamentation region on the laser pulse power are measured. The existence of a relative power interval in which the explosive growth of the number of filaments occurs, is established.

Multiple filamentation of collimated beams Ti:Sapphire-laser in water

The results of experimental studies of filamentation of femtosecond laser pulses in water is presented. Measured the number of filaments, the spectral width of the laser radiation, nonlinear focusing distance, the diameter of the field of filamentation power laser pulses. Noted the existence of plot on the scale of the relative power in passing which the explosive growth in the number of filaments.