A5031856521- Glass properties and applications
- Luminescence Properties of Advanced Materials
- Laser Material Processing Techniques
- Thin-Film Transistor Technologies
- Silicon Nanostructures and Photoluminescence
- Phase-change materials and chalcogenides
- Semiconductor materials and devices
- Building materials and conservation
- Photonic and Optical Devices
- Nuclear materials and radiation effects
- Surface Roughness and Optical Measurements
- Photorefractive and Nonlinear Optics
- Transition Metal Oxide Nanomaterials
- Photochemistry and Electron Transfer Studies
- Analytical Chemistry and Sensors
- Photodynamic Therapy Research Studies
- Nonlinear Optical Materials Studies
- Laser-induced spectroscopy and plasma
- Electronic and Structural Properties of Oxides
- Ion-surface interactions and analysis
- Diamond and Carbon-based Materials Research
- Cultural Heritage Materials Analysis
- Advanced Surface Polishing Techniques
- Advanced Fiber Optic Sensors
- Spectroscopy and Laser Applications
University of Latvia
2012-2024
Tokyo Institute of Technology
2000-2011
Japan Science and Technology Agency
2003-2011
Physikalisch-Technische Bundesanstalt
1996-1998
University of Münster
1992
Georgi Nadjakov Institute of Solid State Physics
1978-1989
An insight into the present understanding of point defects in simplest and most radiation-resistant oxide glass, glassy silicon dioxide (silica) is presented. The their generation processes α-quartz forms are significantly different. only defect, confirmed to be similar both materials, oxygen vacancy. In silica, additional dangling bond type generated from precursor sites formed by strained Si-O bonds, modifier ions. optical absorption spectra silica dominated paramagnetic defects:...
Abstract Photosensitivity in nature is commonly associated with stronger light absorption. It also believed that artificial optical anisotropy to be the strongest when created by linear polarization. Contrary intuition, ultrafast laser direct writing elliptical polarization silica glass, while nonlinear absorption about 2.5 times weaker, results form birefringence twice of linearly polarized light. Moreover, a larger concentration anisotropic nanopores elliptically pulses observed. The...
The presence of interstitial oxygen molecules in glassy ${\mathrm{SiO}}_{2}$ has been demonstrated directly by 1064.1 nm $({\ensuremath{\nu}}^{\ensuremath{'}\ensuremath{'}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0)\ensuremath{\rightarrow}({\ensuremath{\nu}}^{\ensuremath{'}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1)$ excitation the forbidden ${O}_{2}$ molecule...
Synthetic silica glass with an optical absorption spectrum dominated by oxygen dangling bonds (nonbridging hole centers, or NBOHCs) and having negligible (1%) contribution from the usually copresent Si (E\ensuremath{'}-centers), was prepared room temperature ultraviolet photobleaching of high SiOH content (``wet'') silica, irradiated F${}_{2}$ laser (7.9 eV) at $T$ = 80 K. This allowed us to obtain up-to-now controversial NBOHC in vacuum-ultraviolet (UV-VUV) region show that it is...
Abstract It is demonstrated that ultrafast laser writing in silica glass depends on the grade of associated with method its manufacture. Moreover, laser‐written modifications, particular birefringent reveal a dependence geometry writing, is, modification strength voxels smaller than single line structures and multi‐line scanned areas, which can be explained by free carrier diffusion reduced electric field scanning writing. The retardance region produced regime anisotropic nanopores formation...
A sensitive technique for detecting interstitial ${\mathrm{O}}_{2}$ molecules in ${\mathrm{SiO}}_{2}$ is demonstrated by measuring their infrared $\stackrel{\ensuremath{\rightarrow}}{a}X$ luminescence at 1272.2 nm under a Ti-sapphire laser excitation into the ${\mathrm{O}}_{2}\stackrel{\ensuremath{\rightarrow}}{X}b$ absorption band 765 nm. Contrary to case of trapped inert gas matrices, visible emission corresponding direct $\stackrel{\ensuremath{\rightarrow}}{b}X$ transition not found....
The controversial relationship between the intrinsic 1.9 eV photoluminescence (the R band), 2.0 and 4.8 excitation/optical absorption bands is examined for 11 specimens with different OH, Cl, O2 concentrations irradiation histories. direct relation found intensities of R-band luminescence measured 4.0 (IUV) or resonance (1.94 eV) excitation (Ires), although it slightly superlinear, Ires∝(IUV). deviation from exactly constant ratio band in glass samples attributed mainly to inhomogeneous...
The three dominant cathodoluminescence bands in amorphous SiO2 with maxima at 1.9, 2.7, and 4.3 cV are identical to seen photoluminescence (PL) spectra of irradiated or oxygen-deficient SiO2. On the basis previous PL work these (CL) can be attributed non-bridging oxygen (O01) twofold coordinated silicon (Si01) centers. CL excitation mechanism involves also ionic processes. origin ubiquitous blue radioluminescence undamaged α-quartz is different from that 2.7 eV band amor-phous...
This study presents a novel approach to produce phosphorescent coatings on metal surfaces. Strontium aluminates are the most popular modern materials exhibiting long afterglow at room temperature and broad spectral distribution of luminescence in visible range. However, despite large amount research done, methods for synthesis such remain relatively energy inefficient environmentally unfriendly. A long-afterglow luminescent coating containing SrAl2O4:Eu2+, Dy3+ is prepared by plasma...
The electronic structure and the nature of optical transitions in oxygen dangling bond silica glass, nonbridging hole center (NBOHC), were calculated. calculation reproduced well peak positions oscillator strengths well-known absorption bands at 2.0 4.8 eV, recently discovered band 6.8 eV. eV was attributed to transition from sigma between Si nonbonding pi orbital on oxygen. uniquely small electron-phonon coupling associated with is explained by stabilization Si-O excited state...
Color centers contributing to the optical absorption spectrum of synthetic silica glass in near infrared vacuum UV range are reviewed. Intrinsic defects related oxygen deficiency characterized: E'-centers, vacancies, divalent silicon and excess: dangling bonds, peroxy radicals, interstitial ozone molecules. The properties common impurities/dopants silicas used laser optics discussed.
Formation and decay of nonbridging oxygen hole centers (NBOHC, an dangling bond) in SiO2 glasses by F2 excimer laser (7.9 eV) irradiation were situ analyzed monitoring 1.9 eV photoluminescence NBOHC using a pump probe technique. In wet SiO2, the SiO–H bond was efficiently photolyzed photons to form with quantum yield ∼0.2. However, recombination dissociated hydrogenous species suppressed buildup NBOHC. dry contrast, formation dissociation strained Si–O–Si bonds inefficient but accumulated...