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We present a low-temperature versatile protocol for the fabrication of plasma nanocomposite thin films to act as tunable emitters and optical gain media. The films are obtained by the remote plasma-assisted deposition of a 4-(dicyano-methylene)-2-methyl-6-(4-dimethylamino-styryl)-4H-pyran (DCM) laser dye alongside adamantane. The experimental parameters that determine the concentration of the dye in the films and their optical properties, including light absorption, the refractive index, and luminescence, are evaluated. Amplified spontaneous emission experiments in the DCM/adamantane nanocomposite waveguides show the improvement of the copolymerized nanocomposites’ properties compared to films that were deposited with DCM as the sole precursor. Moreover, one-dimensional distributed feed-back laser emission is demonstrated and characterized in some of the nanocomposite films that are studied. These results open new paths for the optimization of the optical and lasing properties of plasma nanocomposite polymers, which can be straightforwardly integrated as active components in optoelectronic devices.

In this work, we present our magnetron sputtering based methodology to produce amorphous silicon coatings with closed porosity, as a strategy to fabricate solid helium targets, in the form of supported or self-supported thin films, for nuclear reactions. We show how by changing the He working pressure it is possible to obtain highly porous homogeneous structures incorporating different He amounts. These porous coatings (a-Si:He) are very reproducible from run to run, and the high He amount incorporated makes them excellent candidates for solid He targets. The possibility of producing self-supported films is illustrated here, and its potential use in inverse kinematics experiments with radioactive beams is shown through the dispersion in forward geometry of a stable 6Li beam. Also the elastic scattering cross-sections for proton from helium were determined using an a-Si:He coating. The results agree well with the ones reported in the literature. These two examples validate our coatings as good candidates to be used as solid He targets in nuclear reactions. The stability of He inside the coatings, fundamental for its use as solid He targets, was investigated, both over time and after irradiation. The coatings proved to be very stable, and the amount of He inside the pores remains unaltered at least 2 years after deposition and after high irradiation fluence (5 × 1017 particles/cm2; with a dose rate of 5 × 1012 particles/(cm2 s)).

We compare the morphology and optical response of plasmonic nanostructures produced by pulsed laser deposition, consisting of a 2D distribution of Ag nanoparticles exposed to air or buried under an amorphous Al2O3 layer whose thickness is tuned in the 0.5 to 14 nm range. We observe that the covering process leads to drastic changes in Ag content, which are interpreted in terms of sputtering of Ag atoms promoted by the incoming Al ions. This Ag sputtering process is avoided as soon as the nanoparticles are embedded under a subnanometer-thick layer of amorphous Al2O3. Meanwhile, the spectral position of the nanoparticles¿ characteristic surface plasmon resonance, measured immediately after the film growth, is not significantly affected by the deposition of the covering layer. Nevertheless, the resonance band associated with uncovered Ag nanoparticles has vanished after 12 months, as a result of their oxidation. Embedding the nanoparticles under a subnanometer-thick layer of amorphous Al2O3 is enough to avoid the observed atmospheric aging processes as well as to preserve the features of their surface plasmon resonance. The results presented here are therefore promising in view of the pulsed laser deposition-based elaboration, at the wafer scale, of robust and stable tailor-made plasmonic substrates that may potentially present high electromagnetic coupling with their environment due to the very small distance to the nanostructure surface. © 2013 American Chemical Society

This work reports the synthesis at room temperature of transparent and colored WxSiyOz thin films by magnetron sputtering (MS) from a single cathode. The films were characterized by a large set of techniques including X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry (RBS), Fourier transform infrared (FT-IR), and Raman spectroscopies. Their optical properties were determined by the analysis of the transmission and reflection spectra. It was found that both the relative amount of tungsten in the W–Si MS target and the ratio O2/Ar in the plasma gas were critical parameters to control the blue coloration of the films. The long-term stability of the color, attributed to the formation of a high concentration of W5+ and W4+ species, has been related with the formation of W–O–Si bond linkages in an amorphous network. At normal geometry (i.e., substrate surface parallel to the target) the films were rather compact, whereas they were very porous and had less tungsten content when deposited in a glancing angle configuration. In this case, they presented outstanding electrochromic properties characterized by a fast response, a high coloration, a complete reversibility after more than one thousand cycles and a relatively very low refractive index in the bleached state.