This PDF file contains the front matter associated with SPIE Proceedings Volume 7586, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

In this work, we show that the resonant angle of surface plasmons (SPs) excited on a unique type of nanostructured metal can be significantly different from the calculated values. We also find that the excitation of SPs can significantly enhance photoelectron emission on the structured metal surfaces.

Biological materials can be highly heterogeneous at the nanometer scale. The investigation of nanostructures is often hampered by the low spatial resolution (e.g. spectroscopic techniques) or very little chemical information (e.g. atomic force microscopy (AFM), scanning tunneling microscopy (STM)) provided by analytical techniques. Our research focuses on combined instruments, which allow the analysis of the exactly same area of a sample by complementary techniques, such as AFM and Raman spectroscopy. Tip-enhanced Raman spectroscopy (TERS) combines the high spatial resolution of AFM or STM with the chemical information provided by Raman spectroscopy. The technique is based on enhancement effects known from surface-enhanced Raman scattering (SERS). In TERS the enhancing metallic nanostructure is brought to the sample by an AFM or STM tip. With a TERS-active tip, enhanced Raman signals can be generated from a sample area as small as 10-50 nm in diameter. AFM analysis of bacterial biofilms has demonstrated their heterogeneity at the nanometer scale, revealing a variety of nanostructures such as pili, flagella, and extracelullar polymers. TERS measurements of the biopolymers alginate and cytochrome c have yielded spectroscopic fingerprints even of such weak Raman scatterers, which in future can allow their localization in complex matrices. Furthermore, biofilms of the bacterium Halomonas meridiana were studied, which was found to be involved in the generation of the mineral dolomite. Only combined AFM-Raman analysis was able to identify the nanoglobules found in laboratory cultures of H. meridiana as dolomite nanoparticles. Our combined setups are and will be applied to the investigation of biofilms, fish spermatozoa as well as biological membranes.

We discuss in this paper the feasibility of dynamically modulating both resonance wavelength and spectral width of single nanostructures exhibiting plasmonic effects by cycling through a metal-insulator transition (MIT) in vanadium dioxide (VO₂). Using full-field 3D finite-difference time domain (FDTD) simulation method with nonuniform mesh techniques, we study the effects of this modulation by varying the lateral dimensions of these nanostructures from 40 nm to 120 nm radially and changing its configuration as well, that is VO₂ nanodisk on gold one and vice-versa. As an initial step towards fabricating those single composite nanostructures showing the greatest modulating effect, we start by making single NPs of VO₂ and single gold NPs embedded between two 60 nm layers of VO₂. The samples are fabricated on 130 μm thin glass substrates by electron-beam lithography, pulsed laser deposition of VO₂ and electron-beam evaporation of gold. Using confocal extinction spectroscopy, we hereafter provide for the first time experimental observations of spectral tuning in these lithographically prepared single nanostructures. However, we discussed the variability in spectra obtained. Indeed, as the gold NP size decreases, it becomes comparable to the domain sizes of the embedding VO₂ and this prevent the correct acquisition of the flat field. Hence the study of the tunability of gold particle plasmon resonance is imparted. However, we conclude that this study will be feasible for truly hybridized NP, that is gold nanodisk stacked on VO₂ nanodisk and vice-versa. As hinted by our simulation studies and preliminary experimental results, these hybridized composite NPs could potentially be used in the dynamic spectral tuning of plasmonic waveguides.

We investigate the functioning of an innovative monolithically integrated surface plasmon resonance (SPR) device comprising a metal coated SiO₂ layer deposited atop a photoluminescence emitting quantum well (QW) wafer. The device takes advantage of the uncollimated and incoherent emission of QW microstructure. This presents a non-trivial problem in our goal to describe quantitatively the functioning of such a device. We discuss the results of our calculations based on a rigorous coupled-wave analysis algorithm and tensorial approach aimed at the full description of surface plasmons (SPs) coupling in QW semiconductor-based SPR architectures designed for biosensing applications. The results indicate that the injected in-plane wavevectors increase the SPs coupling efficiency up to 10³ times in comparison to indirect SPs injection. We discuss the general idea of an experimental setup required for collecting the 3D measurement of SPR dispersion relations hω(k_x,k_y), potentially enabling a much richer picture of surficial biochemical events. Preliminary results indicate that the proposed methodology produces simultaneously the equivalent of 10⁵ to 10⁸ conventional SPR scans achievable with commercial systems.

ZnO nano-crystals have been paid a great attention as building blocks for the optoelectronic devices. We have been succeeded in growing ZnO nanostructures, such as vertically-aligned ZnO nanowires and nanowalls, by a newly developed nanoparticle-assisted pulsed-laser deposition (NAPLD) without using any catalyst. Depending on the growth condition a film-wire heterostructured ZnO were synthesized on the c-plane sapphire substrates. The room temperature photoluminescence spectrum of synthesized ZnO nanostructures exhibited a strong intrinsic UV emission and a week defect-related visible emission.

Nanophotonics, a novel optical technology, utilizes the local interaction between nanometric particles via optical near fields. The optical near fields are the elementary surface excitations on nanometric particles. Of the variety of qualitative innovations in optical technology realized by nanophotonics, this talk focuses on fabrication. A realization of an ultra-flat silica surface with angstrom-scale average roughness using noadiabatic optical near-field etching and repairing are demonstrated and its origin is discussed.­

We report on the application of a compact laser plasma EUV source for processing of polymer materials. The EUV radiation in the wavelength of about 5 to 50 nm was produced by irradiation of xenon or krypton gas puff target with Nd:YAG laser operating at 10 Hz and delivering 4 ns pulses of energy up to 0.8 J per pulse. The source was equipped with a grazing incidence axisymmetrical ellipsoidal mirror to focus EUV radiation in the relatively broad spectral range with the maximum near 10 nm. The size of the focal spot was about 0.5 mm with the maximum fluence of 70 mJ/cm² in a single pulse. Nanostructuring of polymer materials was achieved, primarily due to direct photo-etching with EUV photons. The results of the studies should be applicable in biomedical engineering.

Self-organized nanostructures (ripples) on the target surface after multi-pulse femtosecond laser ablation exhibit, obviously, a positive multi-pulse feedback in the self-organization process. Experiments on different targets (CaF₂, Si) investigate this feedback in more detail, in particular its dynamics. The influence of pulse number and time separation between successive pulses on both the size and the complexity of the nanostructures as well as the size of the modified surface area is studied. In addition to a dependence on the coupled dose, confirming incubation effects previously observed on ablation efficiency, both modified area as well as pattern feature size and complexity decrease with increasing pulse-to- pulse delay between 1 ms and 1 s, indicating an unexpectedly long lifetime of the feedback. Further, for silicon, a persisting modification of the crystalline structure is found well beyond the ablation spot, though no apparent change in surface morphology can be seen. Mapping the band-to-band photoluminescence displays a spatially modulated dramatic increase of non-radiative recombination compared to unaffected material.

We have studied the fluence dependence of the laser tailoring of colloidal gold particles with radii below R = 25 nm. For this purpose gold nanoparticles in solution have been irradiated with nanosecond-pulsed laser light applying fluences between F = (25 ± 2) mJ/cm² and F = (49 ± 2) mJ/cm². In general, laser tailoring is based on the size and shape dependent localized surface plasmon polariton resonance (LSPPR) of metal nanoparticles. Thus, irradiation with a given laser photon energy is absorbed only by nanoparticles whose LSPPR coincides with the photon energy of the laser light. The absorbed light is rapidly converted into heat, leading to diffusion and evaporation of surface atoms, which permits selective tailoring of nanoparticles. In this contribution, we demonstrate that irradiation of small gold nanoparticles with ns-pulsed laser light, at moderate fluences between F = (25 ± 2) mJ/cm² and F = (41 ± 2) mJ/cm², results in a shape change from non-spherical towards spherical particles. At the same time a defined size reduction of the nanoparticles from (R) = 17.2 nm to (R) = 14.8 nm takes place. Higher fluences initiate nanoparticle coalescence.

Novel metal-oxide multilayer mirrors for water-window wavelengths have been already studied and then fabricated by atomic layer deposition (ALD) or atomic layer epitaxy (ALE) methods which have the self-limiting nature of the surface reactions and can control thickness on an atomic scale over large areas. The reason why metal-oxide multilayer mirrors are effective in the water-window wavelength is that they can prevent the formation of various alloys at the interface resulting in scattering loss, and the absorption of oxygen in oxides is negligible at the wavelength. In this study, high and low refractive materials were chosen to be TiO₂ and Al₂O₃ respectively, because they can be fabricated by ALD or ALE methods and Ti L-absorption edge is located at 2.73nm. We investigated the atomic-scale growth of these films and then found that the growth rates could be constant. Moreover, Al₂O₃/TiO₂ multilayer mirrors were fabricated by the ALE method. As a result, the soft x-ray reflectivity of the 10-bilayer mirror was 1.54%, approximately.

The combination of sample translation and line focusing by cylindrical optics is shown to be a convenient and highly effective way of generating laser induced coherent periodic surface structures (LIPSS) in TiO₂ over significantly extended areas. Compared to known techniques based on a sample translation relative to a circular symmetric focus, the approach is much less time consuming and requires only a single translation stage. The capability of the method to form both high and low spatial frequency LIPSS (HSFL, LSFL) at the second harmonic wavelengths of a Ti:sapphire-laser (around 400 nm) at properly chosen scanning velocity and laser pulse energies is demonstrated. Structured multi-mm² areas with periods of 80 nm and 325 nm were obtained corresponding to distinct sets of optimized parameters. Furthermore, the appearance of nano-bumps on 30 nm scale on the surface of the LSFL is reported. Basic technical issues are discussed and potential applications of LIPSS in rutile-type TiO₂ like superwetting, friction control, catalysis and photovoltaic are proposed.

NMR based on laser-polarized ³He gases has been attracted as a powerful tool for characterizing physical parameters of porous media and then imaging human lungs. In this paper, the feasibility study of nuclear polarization of ³He atoms utilizing the 2³S-3³P transition at 389 nm is reported in comparison with the conventional 2³S-2³P transition at 1083 nm. The 389-nm light has been available readily with the development of various indium gallium nitride light-emitting diodes (InGaN LEDs). In this work, the frequency-doubled light of a 778-nm CW Ti:sapphire laser with the nonlinear crystal (BiB₃O₆) was used as the optical pumping light at 389 nm. The other light from a Littrow external cavity diode laser was also used for optical pumping at the 1083-nm wavelength and then measurement of the nuclear polarization. The nuclear polarization of 1.8% with optical pumping at the 23S-33P transition was demonstrated and then it was found that the (2³S₁, F=1/2)-(3³P₀, F=1/2) transition was the most efficient transition of 2³S-3³P lines for the magnetic field of 1.6 mT and the gas pressure of 0.5 Torr.

Photodeposition (PD) from solutions has been used for realizing various thin film patterns of sub-microscopic thicknesses i.e., 5-500 (nm) to produce various spatially distributed components for optical applications. During PD nanometer particles appear on the irradiated zones of any transparent substrates, such as glass used in this investigation. In this work, Continuous Wave (CW) Photodeposition from a-Se colloid solutions onto glass substrates a Xenon UV-Visible lamp has been employed. We evaluated the morphology of ultra-thin a-Se photodeposited nanostructures obtained by direct deposition of a-Se on glass substrates serving as waveguides by a new technique based on capturing the evanescent light leaking image, named Differential Evanescent Light Intensity (DELI). We obtained that deposition fluencies of about F ≈ 300 J/cm² were enough to produce layers up to about 340 nm thickness, similar to values needed for CW Ar⁺ ion laser PD deposition at λ = 498 nm reported in previous investigations.