Aleksandr P. Zhevlakov

The possibility of controlling the optical limiting effect by a weak light signal

When investigating the nonlinear transmission of fullerene-doped π-conjugate organic structures, it has been found for the first time that the broad-band light of a flashlamp has considerable impact on the optical limiting of infrared laser emission (λ=1315 nm).

Photodynamics of nonlinear fullerene-containing media

The results of theoretical and experimental studies on photodynamics and mechanism of nonlinear optical processes, responsible for optical limiting of power radiation in the wavelength range from 0.3 to 1.3 microns, are presented. Peculiarities in the mechanisms of optical limiting for different fullerene-containing matrices, including solutions, solid-state and polymer systems, are shown.

CARS technique for geological exploration of hydrocarbons deposits

We developed a Raman lidar with ultraspectral resolution for automatic airborne monitoring of pipeline leaks and for oil and gas exploration. Experiments were carried out under the CARS circuit. Minimal concentrations of 200 ppb of heavy hydrocarbon gas have been remotely measured in laboratory tests. Test flights indicate that a sensitivity of 6 ppm for methane and 2 ppm for hydrogen sulfide has been reached for leakage detection. As estimations have shown the reliability of heavy hydrocarbon gas detection by the integration method of seismic prospecting and remote laser sensing in CARS circuit can exceed 80%.

Frequency discrimination in overtone supersonic chemical HF laser

A cw supersonic chemical HF laser with dichroic mirrors and external cavity has been investigated on the first overtone regime. The most intensive line P2-0(4) output power was greater than for any fundamental component.

Iodine photodissociative pulse-repetitive laser: problems of efficiency

We present results of R & D of an iodine photodissociative pulse-repetitive flash-lamp pumped laser with average power approximately 500 W and discuss some problems of its efficiency and scaling. The main problems are follow efficiency of lamp pumping, energetic efficiency of iodine laser, energetic possibilities of active medium and its optical quality, and the closed loop of active medium. In conclusion, the energetic possibilities of developed pulse repetitive laser are discussed, as are some prospects for the near future.

Infrared optics of fullerene-doped organic materials based on polyimide

An optical limiting effect and holographic recording have been studied in conjugated organic materials based on fullerene-doped polyimide at wavelength of 1315 nm.

Action of pulse-periodic and continuous IR radiation on light-controlled vanadium dioxide mirrors

The results of an experimental research of action of the intensive mid IR-range pulse-periodic laser radiation on VO2-mirrors are represented. The damage thresholds of VO2-mirrors are defined for pulse-periodic and continuous radiation and the analysis of the mechanism of their destruction is carried out. The results of numerical simulation of dynamics of switching of VO2-mirrors under the action of pulse-periodic radiation are presented.

Amplification of image brightness by means of the photodissociative iodine laser

A possibility of the amplification of image brightness by the active medium of the photodissociative iodine laser have been demonstrated. The brightness of the test-object image with spatial frequency of 10 mm-1 was amplified 1600 times for Q-switch lasing action and 250 times for free- running one. The contrast of amplified image was equaled 0.8 in both occasions. The smallest input signal achieved the level of 10-13 J per pixel.

IR laser action on fullerene-doped organic systems

An optical limiting of the laser radiation over IR range in organic compounds based on polyimide has been studied. The non-linear transmission at a wavelength of 1315 nm as well as spectral properties of the compounds have been investigated. The result obtained have been explained by the donor-acceptor interaction mechanism that affects nonlinear- optical properties of organic molecules. The fullerene-doped polyimide structures have been determined to be effective optical limiting materials for attenuating a power density of more than 2 J cm2 in the IR range.

Fullerene-doped polyimide systems as effective optical power limiting materials in visible and IR ranges

The optical limiting of the laser radiation over visible and IR ranges in organic material based on polyimide has been studied. The role of the donor-acceptor interaction mechanism in manifestation of organic molecules nonlinear-optical properties has been established. The fullerene-doped photosensitive polyimide structures have been determined to be effective optical limiting materials for attenuating a power density of more than 2 - 4 J(DOT)cm-2.