In this paper, we experimentally demonstrate femtosecond laser direct writing of conductive structures on the surface of native polydimethylsiloxane (PDMS). Irradiation of femtosecond laser pulses modified the PDMS to black structures, which exhibit electrical conductivity. Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) results show that the black structures were composed of β-silicon carbide (β-SiC), which can be attributed to the pyrolysis of the PDMS. The electrical conductivity was exhibited in limited laser power and scanning speed conditions. The technique we present enables the spatially selective formation of β-SiC on the surface of native PDMS only by irradiation of femtosecond laser pulses. Furthermore, this technique has the potential to open a novel route to simply fabricate flexible/stretchable MEMS devices with SiC microstructures.

The effect of the addition of Nb₂O₅ (up to 5 mol%) on the structure and luminescent properties of ZnO-B₂O₃ glass doped with 0.5 mol% (1.32 × 10²²) Eu₂O₃ was investigated by applying infrared (IR), Raman and photoluminescence (PL) spectroscopy. Through differential thermal analysis and density measurements, various physical properties such as molar volume, oxygen packing density and glass transition temperature were determined. IR and Raman spectra revealed that niobium ions enter into the base zinc borate glass structure as NbO₄ tetrahedra and NbO₆ octahedra. A strong red emission from the ⁵D₀ level of Eu³⁺ ions was registered under near UV (392 nm) excitation using the ⁷F₀ → ⁵L₆ transition of Eu³⁺. The integrated fluorescence intensity ratio R (⁵D₀ → ⁷F₂/⁵D₀ → ⁷F₁) was calculated to estimate the degree of asymmetry around the active ion, suggesting a location of Eu³⁺ in non-centrosymmetric sites. The higher Eu³⁺ luminescence emission observed in zinc borate glasses containing 1–5 mol% Nb₂O₅ compared to the Nb₂O₅-free zinc borate glass evidences that Nb₂O₅ is an appropriate component for modifying the host glass structure and improving the emission intensity.

Glasses with the compositions in mol % of 50ZnO:(50 − x)B₂O₃:0.5Eu₂O₃:xWO₃, x = 0, 1, 3, 5 and 10 were obtained by applying the melt-quenching method and investigated by Raman spectroscopy, DSC analysis and photoluminescence (PL) spectroscopy. Raman spectra revealed that tungstate ions incorporate into the base zinc borate glass as tetrahedral [WO₄]²⁻ groups, and octahedral [WØ₄O₂]²⁻ species with four bridging and two non-bridging oxygen atoms. There are also metaborate, [BØ₂O]⁻ and pyroborate units, [B₂O₅]⁴⁻, in the glass networks. The glasses are characterized by good transmission in the visible region, at about 80%. Photoluminescence (PL) spectra evidenced that WO₃ is an appropriate constituent for the modification of zinc borate glass structure and for enhancing the Eu³⁺ luminescent intensity. The most intense luminescence peak observed, at 612 nm, suggests that the glasses are potential materials for red emission.

Advanced gold (Au) and silver (Ag) nanostructures were produced by laser techniques on printer paper substrate. Surface-enhanced Raman spectroscopy (SERS) analyses of the fungicide mancozeb (Dithane DG) and insecticide thiamethoxam (Aktara 25 BG) in quantities smaller than usually applied in agricultural medicine were performed for the first time assisted by the structures fabricated. The investigations and results show an easy alternative and cheap way to detect small amounts or residue of harmful environmental pollutants, which has a direct bearing on food quality and thus on human health.

We report on a new approach toward a laser-assisted modification of biocompatible polydimethylsiloxane (PDMS) elastomers relevant to the fabrication of stretchable multielectrode arrays (MEAs) devices for neural interfacing technologies. These applications require high-density electrode packaging to provide a high-resolution integrating system for neural stimulation and/or recording. Medical grade PDMS elastomers are highly flexible with low Young’s modulus < 1 MPa, which are similar to soft tissue (nerve, brain, muscles) among the other known biopolymers, and can easily adjust to the soft tissue curvatures. This property ensures tight contact between the electrodes and tissue and promotes intensive development of PDMS-based MEAs interfacing devices in the basic neuroscience, neural prosthetics, and hybrid bionic systems, connecting the human nervous system with electronic or robotic prostheses for restoring and treating neurological diseases. By using the UV harmonics 266 and 355 nm of Nd:YAG laser medical grade PDMS elastomer is modified by ns-laser ablation in water. A new approach of processing is proposed to (i) activate the surface and to obtain tracks with (ii) symmetric U-shaped profiles and (iii) homogeneous microstructure This technology provides miniaturization of the device and successful functionalization by electroless metallization of the tracks with platinum (Pt) without preliminary sensitization by tin (Sn) and chemical activation by palladium (Pd). As a result, platinum black layers with a cauliflower-like structure with low values of sheet resistance between 1 and 8 Ω/sq are obtained.