Quantum Confined Intense Light Laboratory

• Novel methods for increasing the peak and average power of laser systems based on multicore optical fibers, spatial light modulators, and coherent beam combining were developed. An efficient method of coherent combining of many optical emitters easily scalable for an unlimited number of channels has been proposed and experimentally verified. Studies of laser beam propagation and amplification regimes in multicore fibers, which are stable at high power and allow dramatic scaling of the peak power of laser systems, were carried out. The possibilities of creating highly localized field structures with controlled parameters in the systems utilizing spatial light modulators and multicore fibers were investigated. A theoretical study of quantum properties of coherent laser beam combining was carried out. The standard quantum noise limit for radiation resulting from coherent combination with a feedback system was found.

• Using supercomputer simulation, the interaction of high-power radiation with the quantum vacuum in the presence of a seed plasma target, namely the development of an electron-positron cascade in the field of laser beams focused in the form of electro- or magnetic-dipole waves, has been investigated. The stability of the investigated regimes against imperfections of the dipole wave synthesis was proven, which gives grounds for the possibility of observing the electron-positron cascade in multi-petawatt laser systems currently being designed. New regimes of interaction of high-power laser radiation with electron-positron plasma leading to the formation of highly localized laser-plasma structures have been discovered.

• The features of the interaction of quantized radiation with matter are investigated under conditions of strong localization of the field and/or interacting particles in various systems. In particular, a theory of photon emission by a nonequilibrium open quantum system in the regime of Purcell amplification in a sub-wavelength quasi-two-dimensional cavity was developed; a systematic theoretical study of bulk and surface polaritons in Weyl semimetals with broken time-reversal symmetry was carried out; and a theoretical model of electron-hole pairs generation by a powerful terahertz pulse in graphene was developed. The theory made it possible to quantitatively explain the results of experiments on nonlinear nano-scale diagnostics of graphene using a nanoprobe illuminated by ultrashort laser pulses. The features of the interaction of X-ray and UV photons with an oscillating absorber, leading to acoustically-induced transparency and the formation of a sequence of attosecond pulses, were investigated. The possibility of the formation of quantum-squeezed light in highly nonlinear chalcogenide optical fibers was shown theoretically for the first time.

• An advanced setup was created for manufacturing and experimental study of the properties of microresonators based on silica and special soft glasses. Various scenarios of the generation of optical frequency combs in silica microspheres, as well as novel methods of exciting Raman generation in chalcogenide microspheres, were demonstrated experimentally. Numerical models of nonlinear and thermo-optical effects in microresonators were developed, the results of which were verified experimentally.

Education and career development:

• The following lecture courses were developed: "Oscillations and Waves, Optics" and "Nonlinear Waves in Optics" for BSc students of the University of Nizhni Novgorod (UNN), "Introduction to Quantum Optics" for MSc students of UNN and PhD students of IAP RAS, "Nonlinear and quantum effects in optical fibers and microresonators " for graduate students and postdocs of the Institute of Telecommunications of the Riga Technical University.

• Two packages of educational and scientific experimental works "Nonlinear propagation of femtosecond pulses in an optical fiber" and "Measurement of ultrashort optical pulses" for UNN students were developed.

• Two tutorials for students have been developed and published.

• Scientific traineeships were organized for laboratory staff on the topics "Squeezing the quantum noise of short pulses of light" at Max Planck Institute for the Science of Light and "Optical frequency combs for classical and quantum communication systems" at the Institute of Telecommunications of the Riga Technical University.

• A traineeship for postdocs from the Institute of Telecommunications of the Riga Technical University was organized at IAP RAS.

• Two laboratory staff members defended PhD theses.

Collaborations:

• Max Planck Institute for the Science of Light (Erlangen, Germany) - scientific collaboration, organization of traineeships - 9 coauthored papers were published, 3 laboratory staff members completed a traineeships.

• Institute of Telecommunications of the Riga Technical University (Riga, Latvia) - scientific collaboration, organization of traineeships - a memorandum of cooperation was signed, 4 coauthored papers were published, 5 laboratory staff members completed a traineeships, a joint postdoc project was launched.

• Texas A&M University (USA) - scientific collaboration, scientific visits - 5 coauthored papers were published.

• University of Queensland (Australia) - scientific collaboration - one coauthored paper was published.

• Sant Longowal Institute of Engineering and Technology, (Punjab, India) - scientific collaboration, joint scientific projects - a memorandum of understanding was signed, two coauthored papers were published, an international RFBR project has been successfully completed.