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Vilnius, Lithuania

Juodkazis K.,Lithuanian Academy of Sciences | Juodkazyte J.,Lithuanian Academy of Sciences | Kalinauskas P.,Lithuanian Academy of Sciences | Gertus T.,Altechna Co. | And 4 more authors.
Journal of Solid State Electrochemistry | Year: 2010

Influence of direct laser writing with femtosecond pulses on electrochemical etching of n-type low conductivity (>1,000 Ωcm) silicon is demonstrated. It has been shown that thermal 1-μ-thick SiO 2 layer on silicon surface can be used as a protective layer in the electrochemical etching process. It has been found that laser ablation changes not only the surface morphology and structure of silicon samples but also the character of their anodic etching in aqueous solution of hydrofluoric acid. Formation of microvoids and caverns of irregular shape has been observed at the laser-ablated sites. It is proposed that the change of silicon conductivity from n-to p-type takes place at the laser fabricated regions. Processes of Si anodic oxidation and electrochemical etching are discussed. © Springer-Verlag 2009.

Buividas R.,Swinburne University of Technology | Mikutis M.,Vilnius University | Mikutis M.,Altechna Co. | Gervinskas G.,Swinburne University of Technology | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

We report on a technique for precise hole drilling in optical fibers using tightly focused femtosecond laser pulses. This direct laser writing approach makes it possible to minimize the amount of waveguide material for uncompromised mechanical performance of the fiber. The proof-of-the-principle of the fiber integration into a microfluidic chip is demonstrated. We show that fabricated holes in the waveguides can be used for measurement of absorption coefficient and refractive index changes at 1×10-3 refractive index units and 2 cm-1 for refractive index and absorption changes, respectively. Simple design and integration possibility of laser-fabricated waveguide sensors is prospective for optofluidic applications. © 2012 SPIE.

Gertus T.,Vilnius University | Gertus T.,Altechna Co. | Kazdailis P.,Vilnius University | Rimeika R.,Vilnius University | And 2 more authors.
Electronics Letters | Year: 2010

The fabrication of surface acoustic wave (SAW) devices by femtosecond laser micromachining has been demonstrated. The interdigital SAW transducers of 50m wavelength were formed on YZ lithium niobate substrate by femtosecond pulse ablation of an aluminium layer. The two-port SAW device has insertion loss of 11dB at 68MHz. The S-parameter measurements revealed no degradation in substrate elastic, piezoelectric, and dielectric properties of the substrate due to laser processing. © 2010 The Institution of Engineering and Technology.

Beresna M.,University of Southampton | Gecevicius M.,University of Southampton | Kazansky P.G.,University of Southampton | Gertus T.,Altechna Co.
Applied Physics Letters | Year: 2011

We demonstrate the generation of optical vortices with radial or azimuthal polarization using a space variant polarization converter, fabricated by femtosecond laser writing of self-assembled nanostructures in silica glass. Manipulation of the induced form birefringence is achieved by controlling writing parameters, in particular, the polarization azimuth of the writing beam. The fabricated converter allows switching from radial to azimuthal polarization by controlling the handedness of incident circular polarization. © 2011 American Institute of Physics.

Maigyte L.,Polytechnic University of Catalonia | Gertus T.,Vilnius University | Gertus T.,Altechna Co. | Peckus M.,Vilnius University | And 5 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

We report experimental evidence of spatial filtering of light beams by three-dimensional, low-refraction-index-contrast photonic crystals. The photonic crystals were fabricated in a glass bulk, where the refraction index has been periodically modulated using tightly focused femtosecond laser pulses. We observe filtered areas in the angular distributions of the transmitted radiation, and we interpret the observations by theoretical and numerical study of light propagation in index-modulated material in paraxial model. © 2010 The American Physical Society.

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