Rafał Miedziński

1,4-dialkoxy-2,5-bis[2-(thien-2-yl)ethenyl]benzenes as promising materials for laser optical limiters

A new promising organic chromophore for two-photon laser absorption at 1064 nm with 1,4-diethoxy-2,5-bis[2-(5-methylthien-2-yl)ethenyl]benzene (A-C) was synthesized. We have performed evaluations of the two-photon absorption for these chromophores incorporated into the polymer matrices. Following the obtained quantum chemical data, we have performed quantum chemical simulations of the third-order susceptibilities for the investigated chrompophore incorporated into the PMMA matrices. The calculations were done within the three-level model. We have established that the experimentally calculated data are a bit less than theoretically calculated; however, the general tendency of their changes shows a good coincidence. The maximally achieved value of the TPA is equal to about 59.2 cm/GW at wavelength 1064 nm, which, together with their high photothermal stabilities, make them good candidates for optical-limiting processes.

OPTICALLY-OPERATED ELASTOOPTICAL EFFECTS IN POLYMER MATRICES WITH NANOCRYSTALLITES

We have found that the optical treatment by bicolor two laser beams at 1064 and 532 nm, at energy densities 80–120 mJ/cm2 originating from the same 10 ns Nd3+ garnett lasers causes the occurrence of the piezooptical effect in 50–80 nm γ-glicyne polymer nanocomposites at nanoparticle content about 6.5% in weighting unit. We propose to use this effect for optical triggers.

Optical and vibrational properties of phosphorylcholine-based contact lenses—Experimental and theoretical investigations

The Raman, MIR and UV-vis spectroscopy have been used to characterize Omafilcon A material constructing the one of the Proclear family contact lenses. The Omafilcon A is hydrogel material composed of 2-hydroxyethyl methacrylate (HEMA) and 2-methacryloyloxyethyl phosphorylcholine (PC) polymers crosslinked with ethyleneglycol dimethacrylate (EGDMA). Vibrational and electronic properties of the Omafilcon A material were also investigated by quantum chemical calculations. Experimentally obtained Raman, MIR and optical spectra were compared to the theoretical ones calculated applying RHF and DFT methodology. The quantum chemical calculations were performed for isolated monomers of lenses compounds as well as for their dimers and trimers to elucidate the effect of Omafilcon A polymerization and the role of an individual components.

Laser Induced Microrelief Superstructure of Ag/ITO Seed-Mediated Nanocomposites

The topography of indium tin oxide (ITO) films with incorporated silver nanoparticles and irradiated by single pulses of 18 ns Nd:YAG laser has been investigated. The study was carried out with two Ag/ITO films having resistances of 50 Ω and 4 Ω/square sheet resistances. The periodic structures in both samples were created after the laser treatment. The photo-induced periodic structures have a different character while the sheet resistance plays a major role in the growth process of these structures. The results of optical and non-linear optical investigations lead us to the conclusion that the temporary polarization of samples and high temperature of illuminated spot during laser treatment is responsible for the shape of periodic structures. This conclusion has been also confirmed by local permittivity measurements using evanescent microwave microscope and theoretical calculations concerning the temperature distributions during laser illumination.

Transparent ITO substrate of seeded silver nanoparticles and formation of photo-induced gratings

Absorption spectra and surface topography of optically modified silver nanoparticles grown on ITO thin layers are here investigated. The study is carried out with two ITO layers respectively having 50 Omega/square and 4 Omega/square sheet resistivity. The surface of the Ni samples are treated by one, three and five single pulses of 20 ns Nd:YAG laser. After the irradiation processes, the grating-like structures of various periods are observed. The result obtained is mainly assigned to the concentration of free electrons that is responsible for the surface plasmon resonance and the heat transfer phenomenon.