This PDF file contains the front matter associated with SPIE Proceedings Volume 7032, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

Carbon nanotubes have been shown to exhibit light antenna behavior, such as polarization and length dependence, and enhancement of incident electromagnetic radiation at resonance. We study and model resonance effects from planar metallic nanoantennas, as a function of nanoantenna dimensions and material properties. We discuss the challenges of designing a two-dimensional nanoantenna array with resonance in the short wavelength (blue-green) region of the visible spectrum, constructed from different materials and in different environments.

We use the discrete dipole approximation (DDA) method to investigate the optical extinction spectra and the E-field enhancement distribution of Ag nanorods with different topologic shapes, such as cylindrical-, needle-, period-, L-, parallel-, U-shaped, and helical nanorod structures. Compared to Ag nanorods with a simple shape such as cylinder and needle, irregular nanorod structures show many distinct plasmon resonance modes over a large spectral range. More hot spots are observed for nanorods with more kinks and bendings, such as period-shaped and L-shaped nanorods, and the E-field distribution depends on the polarization and propagation direction of the excitation light. For the parallel-nanorod structure, when the incident E-field is perpendicular to the nanorod axis, only transverse plasmon modes are excited. However, for a U-shaped nanorod, longitudinal plasmon modes can also be stimulated along the vertical nanorod direction. Helical nanorod interacts differently with left- and right-handed circular polarized lights, which provides another way to tune the plasmon peak and arrange the E-field distribution.

Metallic nanostructures have attracted large interest recently due to new optical properties caused by plasmonic effects. The exceptionally high transmission of light through periodically structured metals is originated by interactions between light and plasmonic resonances. These resonances are controllable by varying periodicity and geometrical dimensions of the metal gratings. Our aim is the utilization of these effects to improve the efficiency of conventional light-emitting diodes (LED). The application of one-dimensional periodic metallic gratings as top electrodes of LEDs offers advantages such as efficient and homogeneous current injection, enhanced light output, modified angular light emission characteristics and linear polarization of the emission. Based on finite-difference time-domain simulations, we optimized the parameters for gold and silver gratings on top of InGaAs/GaAs/AlAs heterostructures. Fabrication of these structures was carried out using laser interference lithography (LIL) and a lift-off process. We measured the optical transmission of these structures and were able to demonstrate a polarization- and wavelength-dependence in good consistency with our calculations.

We have demonstrated the directional control of surface plasmon polariton(SPP) waves through propagating in an asymmetric plasmonic Bragg resonator using femtosecond temporal-phase control via the resonant coupling of SPPs and the interference of SPPs. The near-field images display significant temporal-phase dependence, switching between left and right propagation after the Bragg resonator.

In this paper we propose a general and powerful theory of the plasmonic enhancement of the many-body phenomena resulting in a closed expression for the surface plasmon-dressed Coulomb interaction. We illustrate this theory by computing dressed interaction explicitly for an important example of metal-dielectric nanoshells which exhibits a rich resonant behavior in magnitude and phase. This interaction is used to describe the nanoplasmonic-enhanced F¨orster resonant energy transfer (FRET) between nanocrystal quantum dots near a nanoshell.

The large field intensities and tight field confinements that are readily achievable using nanoscale plasmonic devices offer intriguing new tools for use in quantum optics, single-photon nonlinear optics, and atomic physics. We discuss several methods in which plasmonics can be used to enable the coherent manipulation of single photons and strong nonlinear interactions between them.

We numerically study surface-plasmon (SP) mediated semiconductor light-emitting diodes (LEDs) and show that mediation of SPs can be useful for high power LEDs in their modulation speeds and directionalities. It has been reported that SPs can drastically enhance internal quantum efficiencies and speeds of InGaN quantum-well (QW) LEDs by letting them dominate spontaneous emission (SE) processes. Many experimental and theoretical studies have been conducted in this context but most of the works have dealt SE into SPs and light extraction from excited SPs separately. In particular, there is no theoretical analysis, to our knowledge, which simultaneously considers SE into SPs on a textured metal surface along with its extraction to outside radiation. In this presentation, we numerically study InGaN QW LEDs which consist of 1-D metallic gratings on a p-contact electrode and an adjacent single QW emitting green light by using finite-difference time-domain (FDTD) method. We focus on the case where the first order diffraction of SPs produces lightwaves propagating along the surface-normal direction. SP band-edge effect on SE rate, extraction of SPs into internal-radiation, and angular directionality of final outside-radiation are analyzed. Practical enhancement of LED performances are discussed on the basis of the simulation results.

This paper reports the fabrication of two reproducible surface enhanced Raman scattering devices using; a) nanoPillar coupled with PC cavity by means of FIB milling and electron beam induced deposition techniques (Device 1), and b) plasmonic gold nanoaggregate structures using electro-plating and e-beam lithography techniques (Device 2). Device 1 consists of photonic crystal cavity as an optical source to couple the incident laser with a metallic tapered nanolens. Exploiting such approach it is possible to overcome the difficulties related to scattering and diffraction phenomena when visible laser (514 nm) illuminates nanostructures. The nanostructure is covered with HMDS and is selectively removed leaving HMDS polymer on nanoPillar only. A clear Raman scattering enhancement has been demonstrated for label-free detection of molecule in sub-wavelength regime. On the other hand, myoglobin protein is deposited on Device 2 using drop coating deposition method and is estimated that the substrate is able to detect the myoglobin concentration down to attomole.

Photoluminescence (PL) of poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) in the presence of Silver nanoparticles (NP) is studied. The purpose of this research is to understand the PL distance dependence of plasmon-polymer separation and a correlation between the surface enhanced fluorescence (SEF) and polymer molecular weight. Distinct peaks in PL are found for plasmon-polymer separations ranging from near the far field to the near field, under 100 nm. Extinction of the devices shows that changes in absorption cannot explain all enhancement in PL and suggests that a modification of the radiative lifetime is modified. The dependence of the photoluminescence of MEH-PPV on molecular weight shows variation but overall suggests chain length does not affect film quenching. This is largely attributed to the large polydispersity of the polymer materials used.

Giant electromagnetic field enhancements in the vicinity and within layered nanoparticles supporting surface plasmon resonances provide an excellent opportunity for ultra-sensitive Raman spectroscopy. Using metal nanoparticles, enhancement levels of very high sensitivity are achievable but quantitative control over them has traditionally been poor. We propose here multilayered nanospheres with alternating metal-dielectric layers as optimal and easily tailored probes for enhanced Raman scattering, terming these constructs nano-LAMPs (nano-Layered Metal Particles). A theoretical framework based on electromagnetic scattering calculations is used to describe the influence of parameters of the probes, viz. size, composition and spacing of metal and properties of dielectric layers. A recursive formulation of analytical Mie solution is used to evaluate scattering, and the theoretical tunability of electric field enhancement within the spheres is demonstrated as a function of design parameters. An optimization procedure is devised to obtain optimal configurations under fabrication constraints. While demonstrating significant surface enhancement effects, the optical tunability of nano-LAMPs is shown to provide an ability to design probes for multiple excitation frequencies.

There is a growing need for fast reliable biosensor arrays for disease screening. We have used nanostructured plasmonic gold surfaces for the detection of biological species by surface enhanced resonance Raman scattering (SERRS). Careful, directed placement by Dip-pen Nanolithography (DPN) of the biological species or capture chemistry, within the array facilitates efficient read out via ultra fast Raman line mapping. Further, we can transition the serial placement of biological species / capture chemistry to a massively parallel deposition method, and this flexibility is key to enhancing the throughput of these combined techniques by many orders of magnitude. SERRS is an extremely sensitive spectroscopic technique that offers several advantages over conventional fluorescence detection. For example, the high sensitivity of the method allows detection of DNA capture from single plasmonic array "pixels" ~1 μm² in area. Additionally, the information rich nature of the SERRS spectrum allows multiple levels of detection to be embedded into each pixel, further increasing the information depth of the array. By moving from micro- to nano-scale features, sensor chips can contain up to 105 times more information, dramatically increasing the capacity for disease screening.

We have investigated the aggregation and dissociation dynamics of 6-nm size Fe₃O₄ nanoparticles coated by tetra methyl ammonium hydroxide (TMAH) and the same size γ-Fe₂O₃ nanoparticles precipitated inside an alginate hydrogel matrix, both in aqueous suspensions, using dc magnetic-field-induced time-dependent light scattering patterns. For the Fe₃O₄ ferrofluid, a strong anisotropy in light scattering was observed for light propagating perpendicular to the magnetic field. This behavior is attributed to the aggregation of the nanoparticles into chain-like and column-like structures oriented parallel to the magnetic field. A significantly different behavior is observed for the aqueous suspension of γ-Fe₂O₃ nanoparticles precipitated in alginate hydrogel, for which the application of the dc magnetic field produced little to no change in the light scattering patterns. We attribute this difference to the constrained random distribution of γ-Fe₂O₃ nanoparticles precipitated in the alginate matrix. Correlating the results from this investigation with our previous study of magneto-thermal measurements in ac fields [Vaishnava et al., J. Appl. Phys. 102, 063914 (2007)], we conclude that for a ferrofluid to exhibit significant thermal effects under an ac magnetic field, it should exhibit optical anisotropy by developing a chain like structure under the influence of a dc magnetic field.

Slow light characteristics of plasmonics as well as additional characteristics in the nano scale enable very small cavities of the order of 10^-3λ³. Basic mechanisms and several designs exhibiting also enhanced quality and Purcell factors are described - including whispering gallery mode resonators, photonic band gaps, and nano particles, making such cavities ideal for ultrasensitive probing and strong matter-light interactions.

To decrease the sizes of photonic devices beyond the diffraction limit of light, we propose nanophotonic devices based on optical near-field interactions between semiconductor quantum dots (QDs). To drive such devices, an optical signal guide whose width is less than several tens of nanometers is required. Furthermore, unidirectional signal transfer is essential to prevent nanophotonic devices operating incorrectly due to signals reflected from the destination. For unidirectional signal transfer at the nanometer scale, we propose a nanophotonic signal transmitter based on optical nearfield interactions between small QDs of the same size and energy dissipation in larger QDs that have a resonant exciton energy level with the small QDs. To confirm such unidirectional energy transfer, we used time-resolved photoluminescence spectroscopy to observe exciton energy transfer between the small QDs via the optical near-field, and subsequent energy dissipation in the larger QDs. We estimated that the energy transfer time between resonant CdSe/ZnS QDs was 135 ps, which is shorter than the exciton lifetime of 2.10 ns. Furthermore, we confirmed that exciton energy did not transfer between nonresonant QD pairs. These results indicated that the proposed nanophotonic signal transmitters based on optical near-field interactions and energy dissipation could be used to make multiple transmitters and selfdirectional interconnections.

We investigate the properties of the modes supported by three-dimensional subwavelength plasmonic slot waveguides. We show that the fundamental mode supported by a symmetric plasmonic slot waveguide, composed of a subwavelength slot in a thin metallic film embedded in an infinite homogeneous dielectric, is always a bound mode. Its modal fields are highly confined over a wavelength range extending from zero frequency to the ultraviolet. We then show that for an asymmetric plasmonic slot waveguide, in which the surrounding dielectric media above and below the metal film are different, there always exists a cutoff wavelength above which the mode becomes leaky.

Closed form, approximate expressions are found for the electromagnetic eigenstates of an isolated, finite-length, circular cylinder, of radius a and length L, for the case where ka << 1 but kL is greater than 1 (k is the wavenumber in the surrounding medium). These eigenstates are standing waves of surface plasmons which propagate along the cylinder axis and are reflected, back and forth, between the cylinder ends. When considering a cluster of such cylinders, the combined set of these non-quasistatic eigenstates, arising from each of the cylinders in isolation, form a set of vector fields that is complete in the quasistatic limit. This basis can be used as a starting point for evaluating the electromagnetic eigenstates of the entire cluster or even of a periodic array of such cylinders when one is close to the static regime. These states are used to develop a systematic calculation of the macroscopic electromagnetic response of a collection of such cylinders. Some mistakes made in a previous version of this theory¹ are corrected.

In this paper we present an experimental apparatus capable of measuring the differential scattering cross sections of individual nanoparticles and arrangement of nanoparticles. We show that the mapping a partial differential scattering cross section, qualitative information about the electromagnetic local density of states dominated by evanescent modes scattered by the structure can be obtained.

We show that local fields associated both with overall structural features and with unintended defects can be important in the second-order nonlinear response of metal nanostructures. We first consider noncentrosymmetric T-shaped gold nanodimers with nanogaps of varying size. The reflection symmetry of the T-shape is broken by a small slant in the mutual orientations of the horizontal and vertical bars, which makes the sample chiral and gives rise to a different nonlinear response for left- and right-hand circularly-polarized fundamental light. Measurements of achiral and chiral second-harmonic signals as well as the circular-difference response exhibit a nontrivial dependence on the gap size. All results are explained by considering the distribution of the resonant fundamental field in the structure and its interaction with the surface nonlinearity of the metal. We also prepared arrays of ideally centrosymmetric circular nanodots. Second- and third-harmonic generation microscopies at normal incidence were used to address polarization-dependent responses of individual dots. Both signals exhibit large differences between individual dots. This is expected for second-harmonic generation, which must arise from symmetry-breaking defects. However, similar results for third-harmonic generation suggest that both nonlinear responses are dominated by strongly localized fields at defects.

We study the dielectric constant dependent diffraction phenomena of single slit apertures, both theoretically and experimentally. We experimentally simulate perfect metal and real metal cases by investigating subwavelength diffraction by a single slit, both in nano-optical and in terahertz regimes, keeping the slit-width/wavelength ratio approximately the same for both of frequency regimes. The wave-front in optical regime separates itself into forward propagating beam and surface-bound 90-degree diffracted wave, i.e., surface plasmon polaritons; while the separation of modes is not observed in terahertz regime.

As a bio-molecular-sensor with high sensitivity using surface-enhanced Raman scattering (SERS), we developed two dimensional gold nano-mushroom arrays (G-NAMS). Because the heads of the gold mushrooms are closely placed over all aspects on a surface of substrate, a lot of SERS enable spot, so called "hot spots", are formed. . By using G-NAMS, we observed Raman signals of some bio samples. In the experiment to observe the adenine, which is one of four basis of the gene, dissolved in PBS solution, adenine concentrations of 5 pM could be detected. FDTD simulation indicated, that strong Raman enhancement of G-NAMS occurs due to synergistic action of the hot spots produced between metal nanoparticles, and the optical resonant effect in the alumina layer.

Distributions of electric fields in two-dimensional arrays of gold nanodisks on Si₃N₄ membranes are modeled by use of the discrete-dipole approximation as a function of nanodisk diameter (20 nm to 50 nm), height (10 nm to 100 nm), ratio of the array spacing to diameter (1.3 to 4.7), and angle of incident light. The primary focus is on fields in a plane near the circular gold/vacuum interface with light of 532 nm wavelength incident through the membrane, a configuration that is particularly relevant to potential applications in plasmon-mediated Brillouin light scattering, nanolithography, and photovoltaics. The height/diameter ratio for maximum intensities over this plane is between 0.7 and 1.5 and not strongly dependent on the spacing for a given angle. The average intensity increases with decreasing array spacing and incident angle relative to the substrate normal. This dependence is attributed primarily to a combination of fractional coverage area of the gold and increased excitation of a dipolar contribution to the fields. The incident light at 532 nm simultaneously excites dipolar and quadrupolar surface-plasmon modes. Because the quadrupolar mode has a peak close to 532 nm, its excited fields are approximately out of phase with the incident light.

The physical mechanism underlying multiphoton luminescence in gold is still the subject of debate. To obtain a better understanding of the mechanism, experiments that study the luminescence spectra of single particles are necessary. In this study, the multiphoton luminescence spectrum was measured for surrounding media of different refractive indices. The resulting spectra of single gold nanospheres with diameters in the range of a few tens of nanometers were found to be strongly dominated by the absorption peak of the plasmon resonance. This is in agreement with the theory proposed by Boyd et al. (1986)1. According to Lorenz-Mie Theory, an increase in the refractive index of the surrounding medium results in a redshift of the plasmon resonance spectrum; a corresponding shift in the multiphoton luminescence spectrum has now been found experimentally.

We present a technique for the tunable synthesis of a variety of monodisperse silver nanoparticles. Utilizing different optical wavelengths to irradiate initially grown seed crystals, the size and shape of the products can be controlled. Monitoring the absorption spectrum during growth, we observe that initially the absorption maximum shifts to longer wavelengths and broadens, indicating increasing particle size and dispersion. Remarkably, this effect gradually comes to a halt and reverses, displaying a shift to shorter wavelengths and simultaneously narrower bandwidths, until on completion, a final size and relatively narrow distribution is reached. The final morphology is found to depend on control of the laser wavelength and power. Discs, triangular prisms as well as pyramidal and pentagonal prisms may be produced. A process based on a wavelength dependent self-limiting mechanism governed by the surface plasmon resonance controlling the photochemical reduction of particles is suggested. By a similar mechanism, we show that by using a sodium lamp instead of a laser as an excitation source, a monodisperse sample of nanotetrahedra can be produced.

We present a comprehensive multipolar tensor analysis to investigate the roles of dipolar and higher-order multipoles to second-harmonic radiation from a regular array of noncentrosymmetric L-shaped gold nanoparticles. We find the nonlinear response to be dominated by a tensor component which is associated with chiral symmetry breaking and has strong multipolar character. These findings substantiate our interpretation that one of the major contributors to the optical response of the present sample are structural defects, which break the symmetry and make multipolar contributions to the SH response important.

We examine the enhancement of optical trapping forces due to plasmon resonances of nanoshells. Nanoshells are nanoscale particles with a dielectric core and metallic coating that exhibit tunable plasmon resonances. Theory predicts that the optical trapping force may be three to fifty times larger for trapping-laser wavelengths near resonance than for wavelengths far from resonance [1]. The resonance absorption of nanoshells can be tuned by adjusting the ratio of the radius of the dielectric core, r₁, to the total radius, r₂ [2]. Using back focal plane detection, we measure the trap stiffness of optical tweezers, from lasers at 973 nm and 1064 nm, for single trapped nanoshells with several different r₁/r₂ ratios. Enhanced trapping strengths are not found through these measurements done with single wavelength optical traps. A tunable-wavelength laser trap will enable more conclusive results.

Nanoholes and nanoslits are efficient sources of plasmons on metal surfaces. We use arc-shaped nanoslits in thin silver films for generating sub-wavelength plasmon spots with enhanced optical near-fields. Introduction of a continuous phase delay along the nanoslits shifts the position of the plasmon focus spot. We show experimentally that such a phase control allows to scan the plasmon focus by micrometers with a nanometer precision and to launch it on separate silver nanowires placed in the focal plane. These experiments, demonstrating scanning and multiplexing functionality, show the feasibility of the nanoscale manipulation with optical fields.

Excitation and localization of surface plasmon polariton modes in metal-dielectric structures can be utilized to construct unique nanophotonic materials and devices with tuneable optical transmission. We present selective polariton generator (SPG) designs that demonstrate selective light transmission based on surface plasmon antennae principles. These polarisation-sensitive structures can selectively generate and transport polaritons of a desired wavelength through subwavelength apertures. By specifying geometry and orientation we can control the operational characteristics of these elements. By varying SPG designs around a central nanohole we are able to achieve operation of nanophotonic devices where optical transmission peak wavelengths are controlled via the polarisation state of the incident photons. The design considerations of grating periods, corrugation fan angles, transmission due to inner ring variations, and spectral separation of paired SPGs were investigated along with the potential of flanking the structures with Bragg reflector corrugations. The simulations were compared with the experimental results for agreement of the models, which could lead to experimental investigations of more complex structure.

We have studied magneto-optical responses of gold-bismuth-substituted yttrium iron garnet (Au-Bi:YIG) composite films in which Au particles are embedded into Bi:YIG in two different ways. First type were samples in which planar arrays of Au particles were introduced into the middle of Bi:YIG films using a step-by-step sputtering technique. Second type were granular films fabricated using simultaneous co-sputtering of Au and Bi:YIG; in these films Au particles occupy positions inside composite films in a random way. Absorption bands associated with localized surface plasmon resonances (LSPRs) were observed in transmission spectra of films of both types. In the spectral range of LSPRs, samples of Au-array type exhibited larger Faraday rotation angles as compared with that for reference Bi:YIG films of the same thickness. However, given that the volume fraction of Au particles was nearly the same for both types, the enhancement of Faraday rotation for samples of Au-granular type was insignificantly altered. Experiments showed that of the primary importance is the role of the interfaces between Au particles and Bi:YIG. Theoretical estimations showed that, in samples of Au-granular type, air shells appeared between Au particles and Bi:YIG during fabrication. In fact, annealing needed for crystallization of Bi:YIG films is always accompanied with an expansion of their thicknesses.

We study the photoluminescence of Alq₃ on nanotextured silver surfaces to investigate the feasibility of using plasmon enhancement of radiative rates to improve the performance of organic light-emitting diodes. We observe more than 20-fold increases in photoluminescence and separate the contributions of absorption and emissive efficiency increases. With optimized silver coverage, the fraction of excited states created that fluorescence can be made nearly 100 %, an increase of more than 3 times relative to thin films without silver.

Irradiation of spherical silver nanoparticles in glass by linearly-polarized intense femtosecond laser pulses close to the surface plasmon resonance results in irreversible shape transformations. In this context, the spectral positions of plasmon resonances as a function of particle size and basic shapes are well-understood theoretically and experimentally; however, the dynamical information regarding the laser-induced shape transformation mechanisms is still a matter of interest. To investigate these dynamics we introduce a single-color double-pulse experiment, where the sample is irradiated by two time-delayed pulses of equal intensity. Different nanoparticle shape elongations can be produced depending on the delay between two irradiating pulses. Analyzing the resultant shifts of absorption bands for each delay gives valuable information on the evolution of nanoparticle shape changes. Possible shape modifying mechanisms including nanoparticle ionization, extreme lattice heating and excess energy transfer from the hot nanoparticle to the glass matrix are observed and discussed.

Multilayer titanium photonic crystals are fabricated with the mature integrated circuit (IC) technology, which is similar to the Damascene interconnect process. The photonic crystals that we created have the face-centered-tetragonal lattice symmetry. In each layer, the feature size, height and the spacing of the titanium rods is 100 nm, 200 nm and 300 nm, respectively. To our knowledge, this is at the first time that the three-dimensional titanium photonic crystals are realized successfully with 100-nm line width. The reflectance spectra of three- and four-layer titanium photonic crystals are measured with the Fourier-transform infrared spectroscopy and simulated with the three-dimensional finite different time domain method. Through both the experimental observation and the calculation verification, the characterization of the photonic band gap is demonstrated at near-infrared wavelengths and the optical behavior of titanium photonic crystals is discussed for incident light waves of s- and p-polarization. Moreover, the absorption spectra are derived from the reflectance and transmittance spectra due to the law of conservation of energy. It is found that absorption near the photonic band edge is modified and enhanced in a narrow bandwidth because of the well-known recycling-energy mechanism. The large band gap can suppress black body radiation in the mid-infrared range and recycle energy into the near infrared. According to Kirchoff's law, the absorptance of a body equals its emissivity. Thus, the multilayer titanium photonic crystals would be applied as an efficient near-infrared light source with a narrow bandwidth, and produced on a mass scale with the standard IC technology.

The scattering of electromagnetic (e.m.) waves by small ellipsoidal particles having non-zero dielectric or magnetic susceptibility have been studied extensively. The studies in case the particles have non-zero dielectric as well as magnetic susceptibility have been limited to small uncoated particles of spherical shapes. We present here a study of the scattering of e.m. waves by small ellipsoidal particles having non-zero dielectric as well as magnetic susceptibility. We refer to such particles as magnetic particles. The ellipsoidal particles in our case can have multiple ellipsoidal coatings having common focii and axes. By deriving analytical expressions for the magnetic and electric scattering coefficients for such particles, we show that there is drastic difference between the backscattering as well as forward scattering patterns of the non-magnetic and magnetic particles. We also compare the scattering patterns of magnetic ellipsoidal and spherical particles. Furthermore, we derive Maxwell-Garnett formula for multiply coated magnetic ellipsoidal particles. To our knowledge, our results are new and should be useful for plasmonics and meta-materials designs.

Recent theoretical and experimental studies indicated that at certain conditions surface plasmon oscillations (SPOs) may show non-classical properties. In this study we present the results of our measurements on spatial distribution and photon statistics of the light emitted by surface plasmon oscillations. Both visible and near infrared lasers have been used for generation of surface plasmons. The experiments were performed in the Kretschmann geometry using both gold and silver layers at several laser pumping powers. We used different type of photo detectors in the photon counting regime to measure the statistical properties of the light generated by surface plasmons. The photon statistics have been measured by different methods. Time interval statistics, photon-number distribution and correlation function of the generated light were determined and compared to those of the exciting laser. Correlations between statistical properties of the light emitted by decaying surface plasmons and the exciting laser source have been studied.

Within this work we present a new class of shaped silver nanoparticle ensembles which have demonstrated high sensitivities to variations in the refractive index of their surrounding environment. The ensembles' collective response has proven to exceed that of other sensitivities quoted in literature by various other nanoparticle structures, with sensitivity values of up to 376.6 nm/RIU recorded. A quick, simple sucrose sensitivity test has been developed in which any corresponding shift in the nanoparticles' spectrum can be associated solely to a change in the surrounding refractive index. AFM, TEM and dynamic light scattering characterisation of the mean diameter and height distributions of the nanoparticle ensembles provides information on the relationship between the structural properties of the nanoparticles and their sensitivity.