In this work, the performance of gold nanoislands was investigated for Localized Surface Plasmon Resonance (LSPR) and Surface Enhanced Raman Spectroscopy (SERS) applications. Nanoislands were generated by thermally annealing thin layers of gold (having thickness in the 6-12 nm range), which was previously deposited by vacuum thermal evaporation onto glass substrates. Gold nanoparticles (AuNP) were evaluated based on their plasmonic and SERS performance and morphological properties. Scanning Electron Microscopy (SEM) was used to measure the average particle size and average interparticle distance in order to correlate them with the obtained plasmonic/Raman capabilities. The technological parameters of nanoisland fabrication for optimal performances were also determined.

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It is shown that the well-known blue-shift of the fundamental absorption edge in as-deposited compositionally modulated amorphous Si/Ge and As 6 Se 94 /Se 80 Te 20 multilayers (with periods of 4-8 nm) is further enhanced due to the thermal or laser-induced intermixing of adjacent layers.The laser-induced intermixing process, as supported by experiments and model calculations, can be attributed to both the local heating and photo-effects in As 6 Se 94 /Se 80 Te 20 multilayers, while only the thermal effects were observed for Si/Ge multilayers. Structural transformations, based on this enhanced interdiffusion, provides good capability for spatially patterning optoelectronic devices and digital information recording. a) Corresponding author.

Gold nanoparticles (AuNPs) display surface plasmon resonance (SPR) as a result of their irradiation at a targeted light frequency. SPR also results in heat production that increases the temperature of the surrounding environment, affecting polymerization. The aim was to investigate the SPR effect of AuNPs on a dimethacrylate-based photopolymer system. The tested composites were designed to overlap the illumination required for the polymerization and the plasmon effect. The 5 nm-sized dodecanethiol capped AuNPs were applied in different concentrations in the matrix that were irradiated with green light (λ = 532 nm), where the Irgacure 784 photoinitiator also absorbs the light. The plasmonic effect was investigated for the refractive index change by surface plasmon resonance imaging (SPRi) supplemented by ellipsometry. Moreover, optical transmission and transmission electron micrographs (TEM), diametral tensile stress (DTS), and confocal Raman spectroscopy was performed to determine the degree of conversion (DC) at 1.0, 1.4, and 2.0 mW/cm2 light intensities. It was found that the optimal conditions were at 0.0208 wt% AuNPs concentration and 1.4 mW/cm2 light intensity at which the refractive index change, DTS, and DC data were all maximal. The study confirmed that AuNPs are applicable to improve the polymerization efficiency of dental composite resin.

Surface relief gratings formation in amorphous selenium thin films in two recording configurations with light intensity modulation were studied in situ by real-time atomic force microscopy and diffraction efficiency measurements. We report observation of mass transport effect in films induced by band-gap irradiation when the light polarization of the recording beams has a component along the light intensity gradient ("p-p" scheme of recording) that allows obtaining giant stable gratings in this versatile chalcogenide material. On the contrary, only a pure scalar weak grating caused by photoinduced volume shrinkage is obtained in the "s-s" recording configuration, even for long-term irradiation. Chalcogenide glasses (ChG) are known to exhibit a rich variety of photoinduced changes when illuminated with near bandgap light including changes in mechanical properties, termed as photoplastic effects.1 Among them, the effect of light induced surface deformation and direct fabrication of surface relief gratings (SRGs) in ChG is intensively studied over the last decade both experimentally 2-10 and theoretically.11 Two main types of SRG induced by holographic recording, due to the excitation intensity modulation, with near band-gap light in ChG can be distinguished according to their formation mechanism and their properties:10 (1) small scalar SRG induced by either volume expansion or shrinkage due to different response of the material in the bright and dark zones of the interference pattern formed and (2) giant vectorial SRG induced by lateral mass transport in the case where the light polarization of the recording beams has a component along the light intensity gradient.Experiments have shown that only few compositions of ChG demonstrate both types of SRG. For example, vectorial SRG have been observed only for Se-rich films in the binary As-Se system (As 20 Se 80 ) 10 and for the compositions close to As 40 S 60 in As-S glasses 3 while scalar SRGs are common to all glass compositions of As-S and As-Se glasses. While for As-S glass the above observation (lack of vectorial SRG) could be accounted for by considering the photo-induced polymerization effect in S-rich compositions, 12 in the case of As-Se glasses the effect is not yet well understood. Although elemental amorphous Se (a-Se) is a model glass-former in chalcogenide science, no systematic studies of SRG formation have been carried out up to now, while investigations of other photoinduced effects abound. 13 A fact that perplexes studies of SRG formation relates to the photoinduced crystallization of a-Se (Ref. 14) under band-gap illumination, thus preventing the formation of advanced surface relief stable in time.Few papers report the formation of surface relief induced by holographic recording for a-Se films. 2,5,15 In an early study, Haro-Poniatowski et al.,15 employing phase conjugation, haveshown that small (20 nm in height) photoinduced surface relief gratings appears in 4 lm-thick films with the same spatial period. Slightly higher reliefs ($ 40 nm) formed a...