The first laser in Siberia was created at the Institute of Radiophysics and Electronics of the Siberian Branch of the USSR Academy of Sciences in 1962. Henceforth, research in this field was carried out in two other scientific establishments of Novosibirsk, namely, the Institute of Thermal Physics and the Institute of Theoretical and Applied Mechanics. But in 1991, the Presidium of the Siberian Branch of the USSR Academy of Sciences resolved to establish an Institute of Laser Physics based on the core divisions of the above institutes, and this year the institute already marked its twentieth anniversary. The institute staff members told about their research work to Yelizaveta Sadykova, correspondent of the Nauka v Sibiri (Science in Siberia) newspaper.

Vladimir Denisov, Cand. Sc. (Phys. & Math.), Deputy Director for Scientific Work noted: "Our employees made a major contribution to the creation of a new domain, namely, nonlinear laser spectroscopy of superhigh resolution. It is a matter of great importance, though far from the only one. Our achievements in precision metrology and frequency standards are widely known both in this country and abroad. We were the first in the world to create an optical laser clock. We are also proud of our studies in biomedicine, innovative technologies for industry and the research data of the influence of outer space on space vehicles."

The successes of our institute advances are undoubtedly a result of combined efforts of all its divisions. The laboratory of high-power continuous lasers is the oldest among them. Plants with controlled radiation characteristics are created here. They include a multifunction three-kilowatt CO₂ laser, capable of generating both in the continuous mode and in the pulse-periodic mode, and that with the frequency from units of kilohertz to dozens and even hundreds of kilohertz. Gennady Grachov, laboratory head exclaims: "Just imagine, 120,000 laser pulses per second! One can change frequency of their movement, duration and shape, and, above all, obtain pulse power dozens and even hundreds of times more than in the continuous mode. Moreover, the plant can be tuned to the generation spectrum of CO₂ molecule, which is over 70 spectral lines in the bands from 9 to 11 microns."

Ample opportunities to control radiation characteristics open new trends and fields of application of high-power CO₂ lasers, and the laboratory staff members develop them in cooperation with other research teams of the Siberian Branch of the Russian Academy of Sciences. For example, they develop high-production laser-plasma nanotechnologies of a wear-resistant modification of metal and alloy surfaces jointly with the Nikolayev Institute of Inorganic Chemistry and the Institute of Chemical Kinetics and Combustion. The aerophysical effects of interaction of laser plasma and gas flow (including those for promising configurations of rocket engines) are studied in collaboration with the

Khristianovich Institute of Theoretical and Applied Mechanics. With the participation of the Rzhanov Institute of Physics of Semiconductors, experiments are under way on development of semiconductor heterosystems for a new element base of electronics and high-efficiency solar-energy converters. The laboratory is engaged in search of laser-chemical techniques based on two-wave resonance multi-photon excitation or dissociation and molecule ionization, including methods of laser isotope separation. Integrated laser stations with an effective range of dozens of kilometers are also created here. They are used for ecological monitoring and cloud drift control (including clouds saturated with contaminants) over megalopolises or major airports and also for radar location of aircraft flights and seismic vibration measurements of engineering structures.

And finally, one cannot deny prospects, seemingly fantastic but not ungrounded, for application of high-power CO₂ lasers for creation of deuterium-tritium plasma injectors of controlled thermonuclear fusion plants and also for destruction of space debris.

The laboratory of ultrashort laser pulse physics has another field of activity. Its members suggested principles of femtosecond (10^-15 s) pulse generation in the optical band and its amplification with consequent transformation into superpower analogs based on different circuits. It should be noted in this context that today the world leading research centers make efforts to create laser systems with a peak capacity of the petawatt (10¹⁵ W) level. With the latter being used, peak intensities of the 10²¹-10²² W/cm² order were already reached. The goal is to research 10²⁵-10³⁰ W/cm² level.

How does it concern scientific studies? If we separate the laser systems according to the said criterion, the value 10¹⁸ W/cm² is called relativistic intensity as, under such conditions, an electron in the light wave field assumes a near-light speed. The 10²⁵W/cm² level is called ultrarelativistic, where protons are also accelerated in a light wave field to relativistic speeds.

Achieving of the 10²⁵ W/cm² level will make it possible to check the fundamentals of quantum electrodynamics, which predicts a possibility of observation, under the said intensities, of effects connected with vacuum polarization and its nonlinear optical properties. Vacuum ceases to be isotropic, and its parameters set about to depend on the direction of radiation propagation. With

an intensity increase to 10³⁰ W/cm² (such level is called the Schwinger limit), creation of electron-positron pairs from vacuum is possible.

According to Vladimir Trunov, Cand. Sc. (Phys. & Math.), leading research fellow of the laboratory, realization of the generation condition of X-ray and gamma radiation of the femtosecond duration is of considerable interest. It will allow to diagnose on-line the structure of nanoobjects, the dynamics of their transformation, and the course of chemical reactions. In other words, not only spatial diagnostics (with three-coordinate nanome-terresolution), but also time diagnostics (with femtosecond and, in future, attosecond (10^-18 s) resolution) can be realized. For example, half-attosecond is a characteristic time of electron transition from one orbit to another in hydrogen atom. Creation of attosecond pulse sources will help come down to generation of zeptosecond pulses (10^-21 s). In that case, it will be possible to study the dynamics of intranuclear excitations, fusion reactions and nuclear fission.

As regards practical applications, one of the most promising ones (using laser systems of petawatt and multipetawatt bands) is generation of monoenergetic protons and ions with specified energy for the so-called hadronic therapy, one of the methods of cancerous growth treatment. Contrary to the accelerating systems being developed by nuclear research centers, the proton and ion acceleration schemes, using high-power laser radiation, make it possible to change energy and type of accelerated particles by changing just the material of the target.

The laboratory members develop new generation principles of super-power optical pulses as the conven-

tional linear gain circuit has already reached its practical limit. The approaches under development suggest coherent combining of fields, for which separate channels should be well phased. Hence, it is planned to use the optical clock developed at the Institute of Laser Physics. Proceeding to the generation sphere of superpower optical fields, it will be most probably possible to overcome the ultrarelativistic level of intensities and to reach the Schwinger limit.

Today the laboratory in cooperation with a number of institutes of the Siberian Branch of the Russian Academy of Sciences is engaged in the creation of a starting multipetawatt (>10¹⁵ W) system of the exawatt (10¹⁸ W) laser complex.

Igor Sherstov, senior researcher, spoke of another research trend of the laboratory of infrared laser systems: "The sphere of our interest includes remote and local analyses of the atmospheric gas composition, ecological monitoring and chemical ranging. We are developing CO₂ lasers of our own patented design. Our instruments are used also in medicine. Thus, specific bacteria in the organism of sick persons breathe in their own way. Therefore, we have suggested a laser gas-analyser, which can diagnose the health status of man by the air he breathes out and a gas trace of bacteria."

The laboratory developed a variety of compact lasers. One of them, a portable laser leak detector Karat, was created to register leakage of SF6 , which is widely used in high-voltage and pulsed equipment as a gas insulator. Karat operates in the continuous air sampling mode at a rate of 10 cm³ /s "scrutinizing" the SF₆ equipment and has a built-in rechargeable battery providing continuous operation during six hours. Its threshold sensitivity is very high, at the level of 1 ppb (parts per billion). "With such scrutiny, we have actually no competitors," remarked Sherstov. "The similar production instruments have SF₆ sensitivity at the level of 1 ppm (parts per million), i.e. 1,000 times worse. Based on a similar principle of detection, an explosive vapor leak detector is created. True, this detector is inferior to gas chromatographs in threshold sensitivity and selectivity. However, the primary virtue of our instruments is their on-line operation--as soon as they sense any change they react instantly."

Ye. Sadykova, "Plasma, Femtoseconds, Ultrashort Pulses, Nauka v Sibiri, No. 19, 2011

Photo by V. Novikovfrom the Website of the Nauka v Sibiri newspaper