- We have shown viability of writing information using femtosecond laser beam of birefringent nanolattices in glasses of various systems – from binary to multicomponent. We have determined correlation between parameters of the laser beam - its geometry – and specific characteristics of the glass, the degree of connectivity of the silicon skeleton in the first place. It has been determined that to form nanolattices in multicomponent glasses the number of writing pulses should be bigger by an order of magnitude compared to that in quartz glass (tens and hundreds of pulses). We have proposed to write data by a single impact on the glass with a «comb» of femtosecond pulses while the glass should have nanoporous structure.
- For the first time it has been determined through the example of alkali-silicate glasses that, unlike quartz glasses, formation of nanolattices in multicomponent glasses is caused by redistribution and differentiation of chemical elements inside the nanolattice with concentration of alkali cations its «nanoplains» and almost complete absence in wide zones between the «nanoplains». This discovery will allow manipulating chemical composition and characteristics of glass at nano scale. This finding of chemical differentiation in formation of nanolattices in multicomponent glasses indicates real feasibility of creating new nanochannel structures by selective etching of nanolattices «stretched» into a line, as well as long nanochannels with anisotropic cation conductivity based on modulation of single charge cations in nanolattices.
- New solutions have been proposed for technologies of controlled three dimension crystal structures formation inside glasses. A unique method has been proposed for creating crystal waveguides using focused beam waist with elliptic cross-section. Feasibility of creation of highly homogeneous crystal waveguides inside glasses has been shown. The produces waveguides were characterized by optical loss during transmission that was lower than average values for this type of structures – about 2.6 dB/cm. Moreover, we were the first to register high intensity signal of second harmonic generation at 515 nm wave length at the exit of a crystal waveguide through which femtosecond laser radiation of 1030 nm frequency was propagating.
- An original method has been developed for high precision «erasing» of crystal waveguides that allows to «heal» cracks in their structure. This broadens the toolkit for creating optical circuits based on crystal structures in glasses. It also allows to rewrite damaged fragments of waveguide structure. The method relies of amorphization of a selected region of crystal by local heating of glass during scanning by a laser beam at a speed many times higher than the speed of crystal phase formation. Two options of «erasing» previously written crystal structure have been demonstrated. The first method is for long-haul waveguides and it is implemented using pulses that have energy close to the energy at which crystal growth occurs. It has been determined that by regulating parameters of trajectory location it is possible to amorphize, for example, only a part of crystal track in its depth. The second method is for amorphization of micron-sized local regions. Resolution in this method is limited by density of focusing of the laser beam. An important advantage of proposed methods is possibility of forming another crystal in the region amorphized by the laser beam.
- Our team has proposed methods of writing channel waveguides in activated monocrystals. The methods allow forming luminescent waveguides with low optical loss as well as creating a waveguide laser with diode pumping based on the principle of mode synchronization and generating pulses with ultra high frequency (~11 GHz), We were the first to observe phase transition of Grant to Perovskite-like phase while forming tracks using femtosecond beams on YAG:Nd and YAG:Yb crystals.
- We have proposed a method of laser writing of channel amorphous waveguides in glasses through the example of wolfram tellurite glass doped with bismuth oxide. The method relies on moving the sample orthogonally to the axis of the beam and writing a series of at various pulse energies, frequencies and scan speeds. Single mode waveguide has been created that consists of 32 tracks and has coating with low refraction index. Complete inner loss at 1064 nm wave length is less than 5%. The proposed waveguide design is promising for nonlinear optical conversion, for example for creating supercontinuum in medium IR.
- We have detected the effect of simultaneous formation of polarization-dependent birefringence and luminescence that is caused by formation of nanosectors of silver in zinc phosphate glass. This can serve as a basis for creation of «six-dimensional» optical memory with three independent parameters that can be set during writing a single point. It can also be used for devices with complex profile device of birefringence and luminescence.
- We have found modes of local formation of nanoclusters and plasma nanoparticles of silver in glasses by laser beam as well as waveguide structures containing plasma nanoparticles.
- Our team has created methods of etching of microchannel structures in quartz glass as well as in multicomponent glasses with capability of alternating cross-section dimensions of the channel for demands of microfluidics. We have conducted comparative analysis of modes of laser processing and etching needed for formation of microchannels in these glasses.
Implemented results of research:
- Our laboratory has launched a project of the Prospective Research Foundation of the Ministry of Education and Science of Russia. The project is aimed at developing experimental models of 5D information read/write systems.
- We were the first to show formation of nanolattices in multicomponent glasses with birefringence strong enough for usage in practice. In particular, we have created the first converter of laser polarization of laser beam in multicomponent systems (mark AF32) in the world. A number of such converters manufactured at Mendeleyev University of Chemical Technology of Russia are used in Stepanov Institute of Physics of the National Academy of Sciences of Belarus and in the Center of Fiber Optics of the Russian Academy of Sciences.
- The developed methods of synthesis of glass ceramics with enhanced mechanical properties are used in creating a technology of producing protective screens for new generation displays
- We have developed a number of samples with microstructures with hollow structures in glass that are currently used for developing miniature accelerometers in the «Polyus» Research Center named after M.F. Stelmakh.
Education and career development:
- Our employees defended 2 doctoral and 10 candidate dissertations
- 3 of employees of the Laboratory have completed long-term internships in the University of Southampton (UK)
- We have developed and implemented 12 courses for undergraduate and postgraduate students and issued 3 textbooks: «Materials for electronics and photonics» (postgraduates), «Components based on silicate and high-melting nonmetallic materials» (postgraduates), «Modern methods of research of silicate and high-melting nonmetallic materials» (postgraduates), «Nanostructured materials based on glass-like and ceramic matrices» (postgraduates), «Modern problems of chemical technologies of glass» (masters), «Special technologies of glass» (masters), «Physical chemistry of glass-like matters» (masters), «Chemical technologies of glass ceramic materials» (masters), «» (masters), «New glass-like materials and methods of their synthesis» (masters), «Physical chemistry of glass-like matters» (masters), «» (masters), «Chemical technology of glass» (bachelors), «Special technologies for glass and materials based on it» (bachelors)
- We conduct annual career enhancement courses for undergraduates, postgraduates and young researchers: «New approaches to applications of glass in information technology» and «Controlled formation of nano- and microinhomogeneity in oxide glasses: new approaches and possible application»
Organizational and structural changes:
We have created «NPTsS» LLC for developing innovative technologies for pulling highly durable transparent films to protect screens of mobile devices.
Other results:
- We have received 32 grants from Russian Foundation for Basic Research, Russian Scientific Foundation, Prospective Research Foundation, Presidential grants
- Employees of the Laboratory including undergraduate and postgraduate students participated in 50 international conferences, delivering over 100 keynotes.
- A powerful complex of technological, experimental and analytical equipment has been created in the Laboratory. This complex allows to conduct research in a wide range of tasks related to synthesis and laser modification of glasses and monocrystals including three dimension samples, films, fibers and microspheres. In terms of level of equipment the Laboratory is one of the top level world class institutions for research of laser modification and micromachining of materials. At the same time, the Laboratory has a base for manufacturing high quality glass.
Collaborations:
- «Polyus» Research Center named after M.F. Stelmakh: joint research in research of generation characteristics of fiber lasers, we have shown viability of creation of compact coherent sources of close infrared range.
- Stepanov Institute of Physics of the National Academy of Sciences of Belarus: joint research of waveguiding and luminescent qualities of huntite-like glasses.
- «Elektrosteklo» LLC (Russia): joint research, we have developed R&D models of active elements of miniature solid-body lasers with selective pumping with wide range of luminescence in the close IR region of the spectrum.
- NPO Lavochkin (Russia): joint research of possibility of creating samples of crystallizable glasses in a form of a band
- «Aleks Lab ST» LLC (Russia): joint research, analysis of optic images including birefringent elements on micron scale
- Research Center for Fiber Optics of the Russian Academy of Sciences (Russia): joint research, creation of polarization converters from SHOTT AF32 glass in a form of parallel-plane discs in multilayer structures from nanolattices formed inside them by femtosecond lasers to form laser beams with radial and azimuthal polarization
