Alexey Z. Obidin

Light driven structuring of glasses

Abstract Theoretical and experimental evidence of light driven structuring of glasses is presented. We show that light overcomes Coulomb repulsion and effective electron–electron interaction in glasses under strong light pumping becomes attractive. As the result homogenious distribution of trapped electrons gets unstable and macroscopic electron bunches are grown. At different conditions ordered structures with period 2 μm ± 0.2 μm determined by internal properties of the material are formed. These structures were observed in ablation: surface profile after laser treatment reveals ordered patern corresponding to the light induced electron domains.

Femtosecond laser fabrication of linear graphitized microstructures in a bulk of polycarbonate samples

We have fabricated high aspect ratio straight and curved graphitized lines inside of polycarbonate samples by using a femtosecond laser. Use of a spherical lens with high NA to focusing femtosecond pulse in the bulk of material leads to self-diffraction of laser beam and formation a filamentary structure. We fabricated two kinds of graphitized lines. The first type is a straight line extended in the direction of the laser beam. This type of lines was created by femtosecond laser scanning without pulse overlapping. The second type of graphitized lines is curved lines, which was created by scanning with a significant overlapping of focal spot. We determined conditions of the formation of straight graphitized lines by one femtosecond pulse with diameter about 2 pm and length greater than 1 mm in polycarbonate samples. Mechanism of formation and potential applications of these structures are also discussed.

Light driven self-ordering in fused quartz

Theoretical and experimental investigation of self-ordering in a fused quartz under strong light pumping is presented. It is shown that uniform radiation drives a self-organization process in a random medium and macroscopic spatially ordered structure is formed.

Excimer laser micromachining

Wavelength, pulse energy, repetition rate of excimer lasers as well as beam profile and beam delivery system are highly important parameters for precision machining. In this paper we report features of our excimer lasers and excimer laser systems that have been designed for micromachining. The examples of treatment of different materials are presented. In particular, we provide some new results of microstructuring of the surface of fused silica and also formation of up to 10 mm long microchannels with extremely high aspect ratio. We discovered some liquid forming under certain circumstances due to drilling of microchannels in PMMA. This liquid remains unchanged in the microchannels after the treatment.

Efficient 2 W average power F2-laser

F2-laser (λ = 157 nm) with 2 W average power and 100 Hz pulse repetition rate that worked at the gas mixture F2:He:Ne pressures below 3300 mbar has been investigated. Conditions of obtaining maximum laser efficiency dependent on the excitation system parameters were determined.

Photosensitivity and induced losses in phosphosilicate fibers exposed to 157 and 193 nm irradiation

Photosensitivity and induced losses in phosphosilicate fibers depend on irradiation wavelength. The best induced index/loss relation has been obtained for H2-loaded samples at 157 nm irradiation. Pre-exposure procedure failed to decrease the induced losses.

High photosensitivity of Al2O3-doped fibers to 193 nm and 157 nm excimer laser irradiation

Significant photosensitivity of aluminosilicate fibers (with and without Er codoping) was observed. Effect of photosensitization was demonstrated for the first time for such fibers. Potential to write gratings directly in Er-doped aluminosilicate fibers was demonstrated.