We provide an overview of our recent advances in the manipulation of wetting in inverse-opal photonic crystals. Exploiting photonic crystals with spatially patterned surface chemistry to confine the infiltration of fluids to liquidspecific spatial patterns, we developed a highly selective scheme for colorimetry, where organic liquids are distinguished based on wetting. The high selectivity of wetting, upon-which the sensitivity of the response relies, and the bright iridescent color, which disappears when the pores are filled with liquid, are both a result of the highly symmetric pore structure of our inverse-opal films. The application of horizontally or vertically orientated gradients in the surface chemistry allows a unique response to be tailored to specific liquids. While the generic nature of wetting makes our approach to colorimetry suitable for applications in liquid authentication or identification across a broad range of industries, it also ensures chemical non-specificity. However, we show that chemical specificity can be achieved combinatorially using an array of indicators that each exploits different chemical gradients to cover the same dynamic range of response. Finally, incorporating a photo-responsive polyelectrolyte surface layer into the pores, we are able to dynamically and continuously photo-tune the wetting response, even while the film is immersed in liquid. This in situ optical control of liquid percolation in our photonic-crystal films may also provide an error-free means to tailor indicator response, naturally compensating for batch-to-batch variability in the pore geometry.

The generation, manipulation and detection of single photons enable quantum communication, simulation and potentially computing protocols. However scaling to several qubits requires the integration of these functionalities in a single chip. A promising approach to the integration of single-photon sources in a chip is the use of single quantum dots embedded in photonic crystal waveguides or cavities. To this aim, efficient coupling of the emission from single quantum dots in photonic crystal cavities to low-loss ridge-waveguide (RWG) circuits is needed. This is usually hampered by the large mode mismatch between the two systems. In this work the emission of a photonic crystal (PhC) cavity realized on a GaAs/AlGaAs membrane and pumped by quantum dots has been effectively coupled and transferred through a long RWG (~1mm). By continuous tapering in both horizontal and vertical direction, transmission values (fiber-in, fiber-out) around 0.16 and 0.08% for RWG and coupled PhC waveguide-RWG have been achieved, respectively. This corresponds to about 2.8% coupling efficiency between the center of the PhC waveguide and the single-mode output fiber, a value much higher than what is achieved by top collection. It further shows that around 70% of the light in the PhC waveguide is coupled to the RWG. The emission from quantum dots in the cavity has been clearly identified by exciting from the top and collecting the photoluminescence from the cleaved facet of the device 1mm away from the cavity which enables the efficient coupling of single photons to RWG and detector circuits.

We describe approaches to enhance localized surface plasmons by placing metallic nanoparticles into two different structures: (i) Fabry-Perot (F-P) resonant cavities, and (ii) Photonic crystal slot waveguides. Through synchronization of the plasmonic and resonant modes, electric field at the surface of the nanoparticles is enhanced by a factor of 4~20 compared with the nanoparticles in free space, depending on the device structure and coupling mechanism. We report key differences between the F-P enhancement and the slow-light enhancement to the plasmonic effect in details. This theoretical investigation reveals a new method to strengthen plasmonic resonances and suggests that the sensitivity of existing plasmonic sensors can be further improved if they are integrated with dielectric resonant photonic devices.

We present a quantum nanophotonic scheme to achieve efficient single-photon frequency conversion. This mechanism is essential for integrated nanophotonics, as it can provide access to frequency regimes in which no single-photon sources are currently available. Moreover, such a device could be used as the basis of a photonic frequency-shift-keyed quantum information scheme. The proposed scheme uses a Sagnac interferometer to exploit quantum interference between two transition pathways in a three-level quantum dot. In the proposed scheme, an input photon induces a complete population state transfer on the Lambda-type quantum dot, causing a frequency shift in the outgoing photon. The Sagnac interferometer is used to put the input photon into a superposition of counterpropagating states which interfere at the quantum dot, providing the necessary quantum interference to make the process efficient. We have developed a real-space theoretical approach and a computationally efficient pseudospectral numerical method to invegtigate the full spatiotemporal dynamics of the scattering process. It is shown that the efficiency of the frequency-conversion process approaches unity in the ideal case, and is greater than 80% even in the presence of realistic dissipation.

In this work films of horizontally aligned single-walled carbon nanotubes were thermally and electrically characterized in order to determine their bolometric performance. Studies were conducted on semiconducting carbon nanotubes, metallic carbon nanotubes, and a mixture. Results show that composite morphology along with carbon nanotube chirality play significant roles in bolometer performance, with cracked composite films having higher responsivity and TCR values but increased variability.

We report highly selective emitters based on high-aspect ratio 2D photonic crystals (PhCs) fabricated on large area (2 inch diameter) polycrystalline tantalum substrates, suitable for high-temperature operation. As an example we present an optimized design for a selective emitter with a cut-off wavelength of 2μm, matched to the bandgap of an InGaAs PV cell, achieving a predicted spectral selectivity of 56.6% at 1200K. We present a fabrication route for these tantalum PhCs, based on standard microfabrication processes including deep reactive ion etch of tantalum by an SF6 based Bosch process, achieving high-aspect ratio cavities (< 8:1). Interference lithography was used to facilitate large area fabrication, maintaining both fabrication precision and uniformity, with a cavity diameter variation of less than 2% across the substrate. The fabricated tantalum PhCs exhibit strong enhancement of the emittance at wavelengths below cut-off wavelength, approaching that of blackbody, and a steep cut-off between high and low emittance spectral regions. Moreover, detailed simulations and numerical modeling show excellent agreement with experimental results. In addition, we propose a surface protective coating, which acts as a thermal barrier coating and diffusion inhibitor, and its conformal fabrication by atomic layer deposition.

The multispectral imaging technique consists of imaging a given scene at various wavelengths of interest, each one containing a different spectral information. By analyzing this spectral content, the chemical species that are present can be localized on the image and identified by reconstructing their spectral signature. In this way, following Ebbesen's seminal work in plasmonics [1], purely metallic or hybrid metallodielectric structures [2, 3] seem to be ideal candidates to perform spectral filtering due to their extraordinary transmission efficiency [4] and polarization selectivity. Moreover, their compact feature makes it possible for them to gather in wide arrays of filters that, once integrated into a cooled infrared camera, can achieve real-time multispectral imaging [5]. As seen in Figure 1.d. the spectral signature reconstruction of a chemical species strongly depends on the number of filters and their transmission spectra for the designed matrix. In order to improve the multispectral camera, a complementary approach consists of changing the filter design to realize a tunable filter whose spectral shape can be adjusted in real time according to the imaged scene. We focused our attention on the superposition of subwavelength gratings which seems to be a structure of great potential for multispectral imaging applications [6, 7].

A one-dimensional photonic crystal with termination by a noble metal film–a plasmonic photonic-crystal slab–has been theoretically analyzed for its optical response at a variation of the dielectric permittivity of an analyte and at a condition simulating the molecular binding event. We investigate sensing performance by the slab and show that it is tolerant to the variation of probing conditions and the slab's structural parameters. As a consequence, the considered sensor exhibited an enhanced sensitivity and a good robustness in comparison with conventional surface-plasmon and Bloch surface wave sensors.

In this paper, we present one planar graded photonic quasicrystals based on phyllotaxy structure (PSPQ) to mimic the Luneburg lens. The PSPQ is composed by discrete cylinders, which radius are determined by the index profile of Luneburg lens and Maxwell-Garnett effective medium theory, to mimic the graded index (GRIN) materials. Numerical simulations are performed to investigate the focusing features of the PSPQs by means of finite difference time domain (FDTD) methods. Numerical results show that the PSPQs-based Luneburg lens can focus the light more tightly and efficiently in comparison with conventional graded photonic crystals. Meanwhile, we also explored the focusing properties of PSPQs with different generating angle, which determined the spiral type of phyllotaxy structures, to optimize the focusing behavior of the proposed devices.

We demonstrate that a 2D eight-fold photonic quasi-crystal (PQC) can be produced by a specially designed prism via single-exposure holographic lithography. Compared with traditional eight beams in half space for eight-fold quasi-crystal, we only use 5 beams in ¼ space. From group theory and computer simulation, we have verified the feasibility of the particular configuration and observed the simulated patterns. Experimental results observed under SEM agree well with the expectation, confirming that the specially designed prism can be used to fabricate eight-fold photonic quasi-crystal. This prism-assisted holographic lithography using less exposure beams may benefit mass production of complex quasi-structures.

In this work, we demonstrate a monolithic approach to fabricate free-standing LiNbO₃ photonic crystal (PhC) slabs. Ion implantation is first applied to form a buried lattice-damage layer at a specified depth in bulk LiNbO₃. Photonic crystal slabs are then made with FIB milling followed by wet etching. A high etching rate of 100 nm/min for the implanted layer has been obtained. A vertical PhC profile has been achieved because the bottoms of the milled cones were truncated by an air gap, with a measured slope angle of the hole sidewalls at 89°. Numerical simulation and free-space illumination measurements of the reflectance spectrum over a broadband wavelength were performed to analyse the properties of various PhC slabs. The free-standing LiNbO₃ structures make them easily incorporated into MEMS and show potential applications for tunable optical filters, sensors, and quantum optics applications where high quality, single crystal LiNbO₃ is needed.

Spectroscopic ellipsometry has been used to find the optical constants, including refractive index, extinction coefficient, thickness and volume fraction of nanostructured transparent conducting oxides including indium tin oxide (ITO) and indium zinc oxide (IZO). We observed sharp features in the ellipsometry data, with the spectral peaks and positions depending on the nanostructure dimensions and material. A superposition of Lorentzian oscillators and the effective medium approximation has been applied to determine the volume ratio of voids and nanopillars, thereby providing the effective optical constants.

Recent results on optomechanical and optoacoustic nonlinearities in optical fibres are reported. In a new type of a microstructured silica fibre, comprising two ultra-thin closely spaced glass waveguides, an extremely high and optically broadband optomechanical nonlinearity is shown to occur. This nonlinearity originates from the optical gradient forces between coupled waveguides, can exceed the Kerr effect by many orders of magnitude and allows the formation of stable self-trapped optical modes that represent a novel kind of optical soliton. Furthermore, optoacoustic interaction via electrostriction in the micron-sized core of a photonic crystal fibre is studied. It is demonstrated, that coherent optically-driven acoustic waves, tightly guided in the core, can facilitate in-fibre dynamic optical isolation and all-optical switching.

We use coupled-mode theory with strong perturbation to model the loss and backscattering coefficients of a commercial hollow-core fiber (NKT Photonics’ HC-1550-02 fiber) induced by the frozen-in longitudinal perturbations of the fiber cross section. Strong perturbation is used, for the first time to the best of our knowledge, because the large difference between the refractive indices of the two fiber materials (silica and air) makes conventional weak-perturbation less accurate. We first study the loss and backscattering using the mathematical description of conventional surface-capillary waves (SCWs). This model implicitly assumes that the mechanical waves on the core wall of a PBF have the same power spectral density (PSD) as the waves that develop on an infinitely thick cylindrical tube with the same diameter as the PBF core. The loss and backscattering coefficients predicted with this thick-wall SCW roughness are 0.5 dB/km and 1.1×10^-10 mm^-1, respectively. These values are more than one order of magnitude smaller than the measured values (20−30 dB/km and ~1.5×10^-9 mm^-1, respectively). This result suggests that the thick-wall SCW PSD is not representative of the roughness of our fiber. We found that this discrepancy occurs at least in part because the effect of the finite thickness of the silica membranes (only ~120 nm) is neglected. We present a new expression for the PSD that takes into account this finite thickness and demonstrates that the finite thickness substantially increases the roughness. The predicted loss and backscattering coefficients predicted with this thin-film SCW PSD are 30 dB/km and 1.3×10^-9 mm^-1, which are both close to the measured values. We also show that the thin-film SCW PSD accurately predicts the roughness PSD measured by others in a solid-core photonic-crystal fiber.

Microstructured optical fibers provide a unique environment for new compact sensing of gases as they offer advantages including long optical pathlengths, strong confinement of high power light and extremely small sample volumes compared to free-space gas sensing architectures. Here we investigate the interaction of a modulated magnetic field with guided light to detect a paramagnetic active gaseous medium within a hollow-core photonic bandgap fiber (HC-PCF). This novel fiber-optic approach to Faraday Rotation Spectroscopy (FRS) demonstrates the detection of molecular oxygen at 762.309 nm with nano-liter detection volume. By using a differential detection scheme for improved sensitivity, guided-mode FRS spectra were recorded for different coupling conditions of the light (i.e., different light polarization angles) and various gas sample pressures. The observed FRS signal amplitudes and shapes are influenced by the structural properties of the fiber, and magneto-optical properties of the gas sample including the magnetic circular birefringence (MCB) and the magnetic circular dichroism (MCD). A theoretical model has been developed to simulate such FRS signals, which are in good agreement with the observed experimental results and provide a first understanding of guided-mode FRS signals and dynamics of the magneto-optical effects inside the optical fiber. The results show that microstructured optical fibers can offer a unique platform for studies concerning the propagation of light in linearly and circularly birefringent media.

We report the electromechanical control of spontaneous emission of single InAs quantum dots (QDs) embedded in wavelength-tunable double-membrane photonic crystal cavities (PCC). The tuning is achieved by modulating the distance between two parallel GaAs membranes by applying electrostatic forces across a p-i-n diode under reverse bias. The spontaneous emission rate of single dots has been modified by over a factor of ten, tuning the cavity reversibly between on- and off-resonant conditions without altering the emission energy of the dots. We also discuss a possible approach to integrate the double membrane structure with ridge waveguides, for the transmission of light within a photonic chip.

Phoxonic crystals are periodic structures affecting simultaneously the propagation of light (photons) and sound (phonons) of similar wavelengths. For instance, by introducing periodicity of the order of the micron on semiconductor membranes, a phoxonic band gap for near infrared light and sound at GHz frequencies appears. The insertion of defects can give rise to the simultaneous localization of photons and phonons in cavities and waveguides. Moreover, new structures can be tailored to enhance the light-sound interaction in such small volumes. In this work, the last advances in phoxonic crystal structures (including the so-called optomechanical cavities) will be reviewed. Techniques to inject light and sound in phoxonic structures will be described. Future possible applications of phoxonic crystals, ranging from ultrasensitive sensing to all-optical information storage, will finally be introduced.

In this paper we present an algorithm that maps a reference diffracting structure along an arbitrarily curved boundary. The proposed algorithm produces deformed photonic crystal lattice patches with minimal angular distortion of its unit cells, thus realizing a discrete quasi-conformal transformation of the dielectric map. We then investigate the field confinement characteristics of some curved waveguide devices realized by such structures.

We present a method to map the absolute electromagnetic field strength inside photonic crystals. We demonstrate our method by applying it to map the electric field component E_z of a two-dimensional photonic crystal slab at microwave frequencies. The slab is placed between two mirrors to create a resonator and a subwavelength spherical scatterer is scanned inside the resonator. The resonant Bloch frequencies shift depending on the electric field at the scatterer position. By measuring the frequency shift in the reflection and transmission spectrum versus the scatterer position we determine the field strength. Excellent agreement is found between measurements and calculations without any adjustable parameters and a possible realization is suggested for measurements at optical frequencies.

Photonic crystals that are aperiodic or quasi-crystalline in nature have been the focus of research due to their complex spatial distributions, resulting in high order rotational symmetries. Recently we proposed aperiodic patterns that were rotationally symmetric while being random in the radial direction. The structures are designed by segmenting the circular design space, randomly populating one segment, and repeating that segment about a center of rotation. Studying the symmetries and geometrical attributes of aperiodic structures is typically performed in reciprocal Fourier space by examining the distribution of the Fourier coefficients. This allows the translational symmetry to be directly extracted and the rotational nature to be interpreted. Instead we propose comparing the typical Fourier analysis with the use of a Fourier-Bessel space. The Fourier-Bessel approach expands the dielectric layout in cylindrical coordinates using exponential and Bessel functions as the angular and radial basis functions. The coefficients obtained in this fashion directly provide the rotational symmetries that are present. This work will examine both the Fourier and Fourier-Bessel distributions of the proposed structures as well as other quasi-crystals in order to explore the strengths and weaknesses of both techniques.

We demonstrate a nanostructured broadband absorber in visible range. Two kinds of structures with different absorption ranges are designed and fabricated using nanoimprint lithography. Experiments show a flat absorption spectra with an average absorption of 85% from 400 nm to 700 nm. The proposed structures could be used in the applications of thin-film thermal emitters and photovoltaic devices.

Extraordinary optical transmission through a subwavelength aperture was discovered more than a decade ago. A single subwavelength aperture surrounded by a finite array of grooves on a thin metallic film is a design used by many authors to show subwavelength focusing. In this paper, a modified version of this design is introduced that, to the best of our knowledge, gives best results of this design in terms of the peak power and the full width at half maximum FWHM in the near field as well as the far field of the lens. Numerical simulations using Finite-Difference Time-Domain (FDTD) method coupled with perfectly matched layer (PML) boundary conditions verify that the proposed metallic lens can give a near (far) field focal point 125 nm (1.39 μm) away from lens with FWHM of 245 (299) nm at incident wavelength of 760 (610) nm with power enhancement of at least 2 times over the unmodified design. The dependence of this resonant focusing ability with a certain geometrical parameter defining the modified structure is extensively analyzed in the visible range of spectrum. Such a focusing plasmonic device has potential practical applications like NSOM and FSOM due to the simplicity in its design and fabrication and due to superior results in near and far fields of the lens.

Due to their negative permittivity, plasmonic materials have found increasing number of applications in advanced photonic devices and metamaterials, ranging from visible wavelength through microwave spectrum. In terms of intrinsic loss and permittivity dispersion, however, limitations on available plasmonic materials remain a serious bottleneck preventing practical applications of a few novel nano-photonic device and metamaterial concepts in visible and nearinfrared spectra. To overcome this obstacle, efforts have been made and reported in literature to engineer new plasmonic materials exploring metal alloys, superconductors, graphene, and heavily doped oxide semiconductors. Though promising progress in heavily doped oxide semiconductors was shown in the near-infrared spectrum, there is still no clear path to engineer new plasmonic materials in the visible spectrum that can outperform existing choices noble metals, e.g. gold and silver, due to extremely high free electron density required for high frequency plasma response. This study demonstrates a path to engineer new plasmonic materials in the visible spectrum by significantly altering the electronic properties in existing noble metals through high density charging/discharging and its associated strong local bias effects. A density functional theory model revealed that the optical properties of thin gold films (up to 7 nm thick) can be altered significantly in the visible, in terms of both plasma frequency (up to 12%) and optical permittivity (more than 50%). These corresponding effects were observed in our experiments on surface plasmon resonance of a gold film electrically charged via a high density double layer capacitor induced by a chemically non-reacting electrolyte.

The use of metallic nanostructures for enhanced transmission and near field phenomena have been a topic of extensive research. Here we present integration of active media, consisting of InAs quantum dots (QD) embedded in quantum wells, with 2 dimensional metallic hole arrays (2DHA) leading to a strong interaction between resonant surface plasmons, excited at the metal-semiconductor interface, and intersubband transitions of quantum dots. The presence of a low-loss absorber within the enhanced near field region of 2DHA leads to an enhancement of photoresponse. The parameters of 2DHA were designed to overlap with absorption peaks of QDs. We present techniques of fabrication, accurate characterization of enhancement and efforts to optimize the 2DHA-QD coupling. Over an order of magnitude enhancement in photoresponse is observed due to spectral matching of intersubband absorption of quantum dots to that of 2DHA resonance, optimal placement of QD within the structure, and improved interaction lengths due to lateral propagation. This enhancement is also accompanied by significant narrowing of linewidth and the ability to tune the resonance by varying the 2DHA parameters. A hexagonal lattice with periodic circular holes on a thin gold film is used as the 2DHA. With further optimizations, these structures have significant applications in the mid-wave infrared (3-5 μm) and long-wave infrared (8-12 μm) regions for multispectral and polarization sensitive sensing

Plasmonics mainly deals with light-matter interactions in metallic nanostructures. It has gathered interest since its discovery due to the benefits it provides when compared with photonics and electronics. It owes its popularity to the tremendous number of applications it serves for. In this paper, we review how plasmonic nanoparticles can be utilized in applications such as localized surface plasmon resonance based biosensing and enhancing performance of photodetectors.

Among electromagnetic spectrum, terahertz region has been utilized less due to the lack of appropriate devices that works well in these frequencies But recently growing interest has been focused to design devices with functionality in terahertz region because of potential terahertz applications. We present a novel structure that broadens bandwidth of terahertz metamaterial absorber. Our structure takes a benefit of multiband absorber by making the bands close enough to each other but in a multilayer pattern. The absorber has composed of two concentric copper rings in two different layers followed by polyimide and a metal back layer. Simulation shows 100 GHz bandwidth which is double of that of a single layer single ring absorber.

In this paper, we present two different types of THz spatial light modulators (SLMs) that use dynamic metamaterials (MMs) to enable multiplex imaging. One imaging setup consists of a doped semiconducting MM as the SLM, with multi-color super-pixels composed of arrays of electronically controlled metamaterial absorbers (MMAs). Our device is capable of modulation of THz radiation at frequencies up to 12 MHz with maximum modulation depths over 50%. We have also implemented a different system enabling high resolution, high-fidelity, multiplex single pixel THz imaging. We use optical photoexcitation of semiconductors to dynamically tune the electromagnetic properties of MMs. By copropagating a THz and collimated optical laser beam through a high-resistivity silicon (Si) wafer with a MM patterned on the surface, we may modify the THz transmission in real-time by modifying the optical power. By further encoding a spatial pattern on the optical beam, with a digital micro-mirror device (DMD), we may write masks for THz radiation.

Research on chiral metamaterials has drawn much attention in recent years. By virtue of chirality, for example, it has been shown that chiral metamaterials can achieve negative refractive index without great energy dissipation. In this report, we applied effective parameter retrieval technique to study the material properties of helical metamaterial. The retrieval procedure yields electromagnetic parameters through employing finite-difference time-domain (FDTD) method under periodic boundary condition. We numerically obtain several electromagnetic parameters of the structure and show that the resonance properties and the index of refraction of the helical metamaterial have strong relationship with its circular dichroism. The optical properties of the structure are also discussed, which provides general design guidelines for engineering functional chiral metamaterials.

Visible light communication with LED is an important ICT for the ubiquitous network society. However visible light communication has the speed limit in the conventional blinking LED method. Therefore an active spectral filter would be useful in order to input information signals onto the LED spectrum. Plasmonic spectral filter based on a metalinsulator- metal (MIM) structure is one of the candidates of such active filter. We will explain our progress of fabrication of the MIM structures with the vacuum deposition technique and compare their absorption properties with the theoretical prediction.

Currently, the focused ion beam milling (FIB) technique is a commonly used approach to fabricate nanostructures because of its unique advantages of one-step fabrication, nanoscale resolution, and no material selectivity, etc. However, the FIB technique also has its own disadvantages. Regarding the process of fabrication of the corrugations and subwavelength apertures, nowadays, there is a major problem: the V-shaped structuring. In this work, we discuss the influence of V-shape on the optical transmission of subwavelength slits designed in silver (Ag) and gold (Au) thin films possessing different thicknesses. The effect of different cone angles (ratio between the widths at the incidence plane and at the exit plane) originated from the V-shaped slits was also considered. We had performed computational simulations carried out with COMSOL Multiphysics^® to investigate the slits optical transmission. In most cases, the subwavelength slits were illuminated with 488 nm (for Ag) and 632.8 nm (for Au) wavelength light sources in TM polarization (magnetic H-field component parallel to the axis of the slits). The origin of the slits transmission is attributed to plasmonic surface excitations. Our simulation results demonstrated that different cone angles originated from the Vshaped subwavelength slits generate different influences on the beam propagation. The width variation affects the optical transmission intensity significantly. Hopefully, exploring the influence on the light propagation behaviour through subwavelength apertures via theoretical simulations can provide a better understanding of the beam propagation phenomena for future studies.

Periodic nanostructure arrays consisting of square holes were fabricated with a Focused Gallium Ion Beam on a gold thin film deposited onto the surface of an Er³⁺-doped tellurite glass. The nominal dimensions of the square elements are approximately 300×300 nm², separated by 1.0 μm, such that we have arrays of approximately 15×15, 10×10 and 5×5 μm² dimensions. The metallic nanostructures were vertically illuminated with a diode laser at 405 nm. The Er³⁺ luminescence spectrum in the near-infrared was measured in the far-field via the micro-luminescence technique. The excitation and emission of the Er³⁺ ions were obtained through of the so-called extraordinary optical transmission of excitation and emission light, respectively, via those squares array. In this way, metallic nanostructures sustaining surface plasmons can excite and change the emission properties of the Er³⁺ ions. Additional contributions on the emission spectra were achieved due to the influence of the gold metal film, i.e., the resonant properties from the plasmonic nanostructures can strongly influence the spectroscopic features of the Er³⁺ ions. Therefore, we present a systematic quantum mechanical experiment that shows the quantum plasmonic properties of these nanostructure arrays on the erbium ions, with direct applications for understanding and exploiting of nanophotonic devices.

^{Anderson localization has been a subject of fascination and intense research for more than fifty years. It is highly desirable to harness its curious and interesting properties in practical applications. We have taken a step in this direction by using this phenomenon as the wave guiding mechanism in optical fibers. We have shown, both experimentally and numerically, that for a moderate amount of disorder in optical fibers, transverse localization results in an effective propagating beam diameter that is comparable to that of a typical index-guiding optical fiber.1, 2 In this work, we investigate the effect of macro-bending on the localization properties in a disordered polymer optical fiber both experimentally and numerically. We show that macro-bending in ranges of practical interest does not significantly affect the beam propagation in Anderson localized fibers as long as the strong localization dominates the effect of bending.}

Surface plasmons are coupling waves of electron and electromagnetic field at interfaces of metal and dielectrics or metallic nanostructures and localize at the boundary with nanoscale distribution. So, by using surface plasmons, one can construct integrated optical systems to overcome the diffraction limit of light. Recently, a special electromagnetic mode, called “superfocusing modes”, is important in this research area, owing to high field concentration effect due to increasing of wavenumber of surface plasmons. Metal-coat tapered optical fibers are commonly used for the probes of near-field microscopy and are suitable for fabrication of these superfocusing devices. Furthermore, when these probes are arranged face to face with nano-scale gap, the electric fields in nano-gap also can be enhanced. In this presentation, we show the fabrication processes and numerical analysis of these metal cone structures consist of tapered optical fiber pairs on chip.

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