"The Project aims comprehensive experimental and theoretical studies of interaction of ultrashort laser pulses with optical glasses in order to reveal mechanisms of formation of extraordinary structures induced by laser radiation inside the bulk glass and to establish principles of controlled generation of desired glass modifications for applications in photonic devices. Optical glasses have become the key materials of optoelectronics and photonics applications due to their relatively low costs, processability, and possibility to govern refractive indexes. Recent research has shown that, applying femtosecond laser pulses to glass materials, one can create three-dimensional patterns with nano-scale features whose origin has not yet been understood. These findings can open new opportunities for a broad variety of microsystems with nanofeatures. However, further development of laser-writing techniques for controllable generation of desired modifications in transparent materials is impossible without deep understanding of the governing mechanisms of laser-driven material transformations. The Project will overcome the gap between the striking experimental findings of laser-induced glass modifications and theory which is still unable to explain a number of laser-created extraordinary structures. The objectives of this multidisciplinary project are (1) to disclose the nature of formation of volume nanogratings in fused silica; (2) to find mechanisms responsible for anisotropy of direct writing of optical elements dependent on the direction of laser beam scanning; (3) to describe bubble chains formation in glasses, and (4) to develop a concept of laser-induced modification diagrams for transparent materials. Its real outcome will be in making an important step from a primitive concept of simple energy deposition on laser processing of materials toward understanding and more sophisticated description of overall phenomenon of laser-matter interaction."