Poster session II
A statistical based optimisation routine for the design of,metamaterial structures
Dublin City University (Ireland) Due to the increased complexity of Metamaterials geometric structures, exacerbated by the increased interest in generating inhomogeneous and anisotropic metamaterials, direct optimisation of these designs using conventional approaches often becomes impractical and
limited. In order to alleviate this issue, we propose an alternative optimisation approach which exploits the Kriging methodology in conjunction with an adaptive sampling plan to simultaneously
optimise multiple conflicting objectives.
Metamaterials built by self-folding split ring resonators
Che-Chin Chen (1), Takuo Tanaka (2), Atsushi Ishikawa (2), Ming-Hua Shiao (1), Hai-Pang Chiang (3), Din Ping Tsai (4)
(1)Instrument Technology Research Center - NARlabs (Taiwan), (2)Metamaterials Laboratory - RIKEN (Japan), (3)National Taiwan Ocean University (Taiwan), (4)Research Center for Applied Sciences - Academia Sinica (Taiwan) We present several types of metamaterials (MMs) constructed by three dimensional split ring resonators (3D SRRs). The 3D SRR was assembled from a two dimensional (2D) template by means of a metal-stress driven self-folding method. The desired metamaterials such as infrared-, uniaxial isotropic-, and toroidal MMs can thus be fabricated through arranging the sizes and positions of 2D templates appropriately.
Compact triple-band metamaterial inspired monopole antennas
Yongjun Huang, Xuefeng Zhao, Kaimin Wu, Jian Li, Guangjun Wen
University of Electronic Science and Technology of China (China) Here we present a comparison analysis on the single loop resonator (SLR) inspired triple-band monopole antennas. Two configurations with rectangular and circular shaped radiation patches are presented. Simultaneously, two feed techniques with coplanar waveguide and microstrip feeds are performed to drive the antennas. And the conventional planar monopole antennas without the SLRs are also analyzed comparatively. Numerical and experimental methods are performed to demonstrate and discuss the proposed designs.
A coplanar wideband antenna based on Metamaterial Refractive Surface
Ridha Salhi, Mondher Labidi, Fethi Choubani
Innov'Com-Sup'Com (Tunisia) In this paper we firstly present a wide band forked antenna. It can be useful for on-body applications because of its small size. Then, the metamaterial reflective surface(MRS), which is very efficient as a filter, is used in many simulations to optimize the antenna's performance. Finally, a comparative study between different configurations of the fork antenna with MRS is presented.
Design and simulation of Metamaterial Refractive Surface
Ridha Salhi, Mondher Labidi, Fethi Choubani
Innov'Com-Sup'Com (Tunisia) This paper investigates the performance of metamaterial refractive surface(MRS),where its properties and geometrical conguration are optimized to operate in the frequency range from 1 GHz to 15 GHz. Indeed, the performance of the considered MRS is studied for dierent parameters, such as periodicity, substrate type and MRS width.
Graphene Magnetite Polymeric Nanocomposites (GMPN)-Array Sensor for Human Brain Tumor Detection Using Specific Absorption Rate (SAR) Technique
Mohd A. B. Jamlos (1), Abdul H. Ismail (2), Mohd F. Jamlos (1)
(1)Universiti Malaysia Perlis - UniMAP (Malaysia), (2)Universiti Malaysia Perlid (Malaysia) GMPN-Array sensor is successfully detecting human brain tumor based on SAR technique. The sensor consists of graphene as the radiating element and PDMS Ferrite as the substrate to realize ultra-wide band radiation (2.5 GHz-12.2 GHz) with high energy (2.5dB-6.7dB) in microwave frequency ranges. Amount of energy absorbed by the human brain indicated the present of tumor. Human brain with tumor absorbed more energy and recorded higher SAR value (2.56 W/kg) compared with human brain without tumor (1.07 W/kg).
Performances Analysis of Cylindrical Monopole Plasma Antenna
Hajar Jaafar (1), Mohd Tarmizi Ali (1), Ahmad Nazri Dagang (2), Hanisah Mohd Zali (1), Musfirah Hilmi (1)
(1)Universiti Teknologi MARA (Malaysia), (2)Universiti Malaysia Terengganu (Malaysia) This paper presents the analysis of cylindrical monopole plasma antenna with 3 different gases. Three plasma antennas were fabricated using pyrex glass tubes with length 160mm, diameter 10mm and thickness 1mm. The antennas contain 3 different gases which are Neon, Argon and Hg-Ar with three different pressures which are 0.5 torr, 5 torr and 15 torr. In this work, the Dielectric Barrier Discharge (DBD) method was used to produce the plasma
Building a better metasurface: high accuracy fabrication of plasmonic nanostructures
Sebastian Andreas Schulz, Jeremy Upham, Frederic Bouchard, Israel De Leon, Ebrahim Karimi, Robert W. Boyd
University of Ottawa (Canada) We investigate the relationship between fabrication fidelity and device performance for plasmonic metasurfaces consisting of nanoantenna arrays. We show that intra-structure proximity error correction results in increased fabrication fidelity during electron beam lithography and an associated increase in device performance for plasmonic q-plates. Experimental results show that this proximity error correction strategy increases observed purity values from 0.44 to 0.51, for a corresponding theoretical value of 0.55.
Boost of light trapping with nanostructures for thin film solar cells
Liyang Yue, Bing Yan, Matthew Attridge, Zengbo Wang
Bangor University (United Kingdom) Thin film solar cells have attracted great attention in recent years due to the beneficial features in terms of low production cost, ease of fabrication and potential to have greater efficiencies. This paper aims to design and optimize micro-nano structures for improving the light trapping and absorption capabilities of thin film and latest perovskite solar cell. An optimized design consisting of double plasmonic nanospheres and nanoholes structure was identified, which could produce 70.2 percent absorption enhancement verified by software simulation.
Polarizability matrix retrieval of a non-planar chiral particle through scattering parameters
T. D. Karamanos, N. V. Kantartzis
Aristotle University of Thessaloniki (Greece) An efficient technique for the polarizability matrix extraction of non-planar chiral particles is introduced. Assuming that the particle is electrically-small, we model it via dipoles at its shape center. Then, the induced dipole moments are calculated via equivalent models from the surface's S-parameter response of three normal wave incidences. Finally, by inserting the retrieved dipole moments in the first assumption, the desired polarizabilities are obtained from a linear system via the measured or simulated scattering parameters.
Plasmonic properties of ordered arrays of Ag and Au nanostructures embedded in silica fabricated by a combinacion of nanosphere lithography with ion implantation
Octavio Graniel (1), Cecilia Salinas (1), Erick Flores-Romero (1), Ulises Morales (1), Juan-Carlos Cheang-Wong (2)
(1)Universidad Nacional Autonoma de Mexico (Mexico), (2)Universidad de Guanajuato (Mexico) Nanosphere lithography uses a mask of self-assembled monolayers of spherical silica particles deposited onto silica plates to create regular arrays of nanoscale features in the sample by 1-2 MeV Ag and Au ion implantation. By this way, after removal of the silica particles and an adequate thermal annealing of the as-implanted samples, the formation of Ag or Au nano-objects embedded in silica plates was confirmed by the presence of the surface plasmon resonance in the optical absorption spectra.
Fabrication and characterization of a SEIRA total absorber
Richard Knipper, Thomas G. Mayerhofer, Uwe Huebner, Dana Cialla-May, Karina Weber, Hans-Georg Meyer, Jurgen Popp
Leibniz Institute of Photonic Technology (Germany) Total absorbers are becoming a topic of great interest for spectroscopic applications due to the greatly enhanced signal in applications such as surface enhanced infrared absorption (SEIRA). Here, fabrication and characterization of a total absorber will be discussed, including the performance of the resulting SEIRA device. Application in bio-sensing will be addressed as well as stability and reusability.
Effect of Ar/O2 gas ratio on the optical and electrical properties of ITO/AgOx/ITO multilayer films
Heon Kong, Cheol Jin Park, Jong Bin Yeo, Hyun Yong Lee
Chonnam National University (Korea) We have investigated the properties of multilayer films for application in transparent conducting electrodes. The ITO/AgOx/ITO multilayer films were deposited by rf sputtering technique at room temperature. The effect of AgOx interlayer film on the optical and electrical properties was studied as a function of Ar/O2 gas ratio. The electrical and optical properties of ITO/AgOx/ITO multilayer films were influenced by the thickness and Ar/O2 gas ratio of the interlayer. The optical thickness was simulated by transfer matrix method (TMM).
The role of asymmetry on Fano resonances in metasurfaces
Morteza Karami, Michael Fiddy
University of North Carolina at Charlotte (USA) We demonstrate the effect of additional asymmetries in concentric rings metasurface. The diagonal nonconcentric rings present spectral ultra-narrow band-pass regions which offer practical applications in filters and modulators. Double and triple ring metasurfaces are investigated.
Graphene based ultrasensitive terahertz sensing with dynamically tunable high-Q double Fano resonances
Huiyun Zhang, Tong-Tong Li, Huan-Huan Lv, Xiao-Yan Huang, Yu-Ping Zhang
Shandong University of Science and Technology (China) A graphene based ultrasensitive terahertz sensing with dynamically tunable high-Q double Fano resonances is proposed and demonstrated numerically. Numerical calculation results show that a high sensitivity of 933GHz/refractive index unit and figure of merit of 2.48 can be reached. The introduction of graphene in this sensor can make the sensing range actively tunable. These findings can be conveniently used for the design of ultrasensitive real time chemical and biomolecular sensors in the fingerprint region of the terahertz regime.
Morphing applied to metamaterials
Ronald Aznavourian, Sebastien Guenneau
Institut Fresnel (France) We apply morphing to deduce via numerical interpolation some approximate wave picture of scattering by objects of various shapes deduced from the exact computation (e.g. using a finite element method) of scattering by objects of other shapes, thereafter called the source and destination images.
Elimination of polarization degeneracy in circularly symmetric bianisotropic waveguides
Jing Xu, Bingbing Wu, Yuntian Chen
Huazhong University of Science and Technology (China) Mode properties of circularly symmetric waveguides with bianisotropic chirality are studied using finite element approach. We find that the polarization degeneracy in circularly symmetric waveguides can be eliminated, by introducing magnetoelectric coupling in the waveguide media. Breaking the polarization degeneracy in high order mode groups is also confirmed numerically. A perturbation model is developed to explain the results and shows excellent agreement. Essentially, the bianisotropic waveguides studied here keeps y-polarized modes unchanged, while turns x-polarized modes into leaky modes.
Infrared Beam-steering Using Mechanically Modulated Graphene Monolayer
P. Y. Chen (1), M. Farhat (2)
(1)Wayne State University (USA), (2)King Abdullah University of Science and Technology (Saudi Arabia) We propose a graphene-based infrared beam-former based on the concept of surface leaky-wave. The excitation of infrared surface plasmon polaritons over an acoustically modulated one-atom-thick graphene monolayer is typically associated with intrinsically slow light.
Optical properties of nanostructured metamaterials
Bernardo S. Mendoza, W. Luis Mochan
Centro de Investigaciones en Optica (Mexico) We present a very efficient recursive method to calculate the effective optical response of nanostructured metamaterials made up of particles with arbitrarily shaped cross sections arranged in periodic two-dimensional arrays.
Inverse Transformation Optics with Realistic Material Parameters
Philip Munoz, Orad Reshef, Grant England, Russell McClellan, Eric Mazur
Harvard University (USA) We present a method to generate transformation functions based on a space of achievable material properties. To validate this approach, we consider the range of effective refractive index achievable using silver nanowires in a dielectric background. Given fabrication constraints, we generate a reduced cloaking transformation and confirm its performance using FDTD and FEM simulations. We explore conditions for finding appropriate mappings in restricted parameter spaces, and strategies for optimizing transformations to account for absorption and scattering.
Planar Textile Antennas with Artificial Magnetic Conductor for Body Centric Communications
Kamilia Kamardin (1), Mohamad Kamal A. Rahim (1), Peter Hall (2), Noor Asmawati Samsuri (1)
(1)Universiti Teknologi Malaysia (Malaysia), (2)University of Birmingham (United Kingdom) Two textile antennas namely diamond dipole and coplanar waveguide monopole are designed to test the proposed textile Artificial Magnetic Conductor (AMC). Performance comparison including S11, radiation pattern and gain between the antennas above AMC is observed. Results show gain improvement with reduced backlobes when having AMC. Bending and wetness measurements are also conducted. Bending is found not to cause performance disruption while wetness influences performance distortion. However, once the antennas and AMC dried out, the original performance is retrieved
Plasmonic Antenna for Magneto-Optical Imaging at the Deep Nanoscale
Alex Amy (1), Paul Dawson (1), Mark McMillen (1), Tom Loughran (2), Rob Hicken (2), Paul Keatley (2), Euan Hendry (2)
(1)Queen's University Belfast (United Kingdom), (2)University of Exeter (United Kingdom) We report on the modelling and preliminary experimental data on plasmonic antennas that are being designed and constructed for incorporation into a modified atomic force microscope (AFM) head. The antenna structures are fabricated using a silicon templating technique and the AFM head is the key element in a novel time-resolved scanning Kerr microscope (TRSKM), which is targeted to achieve simultaneous ps-time and sub-wavelength spatial-resolution.
Dynamics of coupled magnetic oscillators excited with picosecond acoustic pulses.
Vishal Shokeen, Alain Carvalho, Jiwan Kim, Jean Bigot
IPCMS - CNRS (France) We report about the magnetization dynamics in two magnetically coupled ferromagnetic films. The structure (Ni/Au/Py) is excited by longitudinal strain pulses generated by femtosecond optical pulses. The measurement of the precession dynamics in both films, using a femtosecond Kerr Magneto-Optical set-up, reveals the coupling between the two oscillators. This work is a new step towards controlling magnetic multilayers or metamaterial devices at a sub-micron scale by inducing a picosecond perturbation of their magnetic moments
Transformation cavity implemented by dielectric posts distributions
Jung-Wan Ryu, Yushin Kim, Inbo Kim, Jae-Hyung Han, Bumki Min, Muhan Choi
Kyungpook National University (Korea) We have shown that highly directional light emission from high-Q whispering gallery modes can be realized in inhomogeneous dielectric cavities which can be defined by imposing spatially-varying refractive index derived from the transformation optics theory. We performed numerical calculation of cavity modes and microwave experiment with a dielectric inhomogeneous cavity made of alumina posts. The result is consistent with our previous theoretical expectation.
Equivalent circuit model for designing of double concentric squares AMC
Mohamad Mantash, Anthony Presse, Anne-Claude Tarot, Sylvain Collardey
University of Rennes1 (France) This paper proposes an equivalent model to estimate the resonant frequency and reflection phase of double concentric square Artificial Magnetic Conductor (AMC). The AMC structure is composed of a double squares of Frequency Selective Surfaces arrays printed on grounded dielectric substrates without vias. This approach is based on the Transmission Line Model for waves normally incident on the structure. The proposed model is validated via a comparison with a full-wave simulation results for different samples and a parametric study.
Miniaturized Bendable 400 MHz Artificial Magnetic Conductor
Anthony Presse, Anne-Claude Tarot
IETR - University of Rennes 1 (France) A bendable Artificial Magnetic Conductor (AMC) with a resonant frequency of 400 MHz is proposed. The dimensions of the unit cell are 50 x 50 mm2. The miniaturization is achieved with closely coupled patches, which are printed on each side of a 0.127 mm thick dielectric substrate stacked on flexible 3 mm thick silicone over a ground plane
Honeycomb-shaped metamaterial absorber for multiband infrared sensing applications
Erdem Aslan, O. G. Saracoglu, Sabri Kaya, Mustafa Turkmen
Erciyes University (Turkey) In this study, a novel metamaterial absorber based on honeycomb shaped gold nanoparticles for infrared detection applications are presented. We demonstrate that the proposed perfect absorber has a dual band spectral response with almost unity absorbance and near field enhancements at the corresponding resonance frequencies are significantly higher than the conventional perfect absorbers. Due to the dual resonances and enhanced near field optical properties of this perfect absorber geometry it can be useful for infrared sensing applications.
Colloidal optical waveguides structured by light
Oto Brzobohaty, Jan Kanka, Lukas Chvatal, Pavel Zemanek
ASCR - Institute of Scientific Instruments (Czech Republic) We present experimental study where we employed dual-beam optical trap to study a self-arrangement of microscopic polystyrene particles into colloidal wave-guides. We investigated magnitude of optical bound between the particles studying thermal motion of self-arranged particles. Such optically bound linear structures can be understood as colloidal wave-guides which self-focus incoming laser light and thus a decreasing of thermal motion of optically bound particles can be observed with increasing number self-arranged particles.
Ultrafast optical-pump terahertz-probe spectroscopy of carrier dynamics in nanoslot-patterned GaAs
Geunchang Choi (1), Young-Mi Bahk (1), Minah Seo (2), Byung Hee Son (3), Yeong Hwan Ahn (3), Dai-Sik Kim (1)
(1)Seoul National University (Korea), (2)Korea Institute of Science and Technology (Korea), (3)Ajou University (Korea) We show carrier dynamics in the nanoslot-patterned antenna arrays on gallium arsenide (GaAs) substrate using optical pump terahertz probe technique. Compared to the bare GaAs, our slot antennas show decreased carrier relaxation time. Moreover, we observe tendency of decreasing relaxation time of the photo-carrier as the antenna width decreases. This result suggests that, by using nanoslot antenna, fast carrier modulation can be achieved.
Electric field enhancement in few nanometer-width antennas operating at gigahertz range
Kwanghee Lee, Jeeyoon Jeong, Jiyeah Rhie, Dai-Sik Kim
Seoul National University (Korea) We investigate electric field enhancement inside few-nanometer-sized gap structure in gigahertz frequency range. Sample is fabricated by atomic layer lithography consisting etching procedure to ensure high-throughput, large-scale, and stable structures. We measure transmitted Ku-band (12~18 GHz) wave through the square ring shaped nanogap arrays by vector network analyzer (VNA) and a pair of rectangular waveguide. Estimated electric field enhancement inside the nanogaps can reach 1,000 and can be even higher with optimized geometry.
Pattern Reconfigurable Monopole Antenna Using EBG Structures
H. A. Majid, M. K. A. Rahim, M. R. Hamid, N. A. Murad, N. A. Samsuri, M. R. Kamarudin, M.F. M. Yusof
Universiti Teknologi Malaysia (Malaysia) A radiation pattern reconfigurable monopole antenna using Electromagnetic Band-Gap (EBG) Structure is proposed. The proposed antenna consists of twelve mushroom-like EBGs positioned around the monopole antenna. The EBG characteristic can be manipulated by controlling the state of switch. The switch is positioned between the EBG's via and the ground plane. By controlling the state of EBGs, the radiation pattern can be reconfigured to an omni-directional pattern and four directional pattern with different angles.
Band-Notched Reconfigurable EBG CPW-Fed UWB Antenna
H. A. Majid, M. K. A. Rahim, M. R. Hamid, N. A. Murad, N. A. Samsuri, M. R. Kamarudin, M.F. M. Yusof
Universiti Teknologi Malaysia (Malaysia) A reconfigurable band notched UWB antenna using Electromagnetic Band-Gap (EBG) structure is proposed. Two EBGs are positioned adjacent to the transmission line of the UWB antenna. The band notched characteristic of the EBG can be disabled by switching the state of switch place at the strip line. The structure produces reconfigurable band notched at 4.0 GHz which covers C-band satellite communication (3.625 - 4.2 GHz) systems.
Optical reflectance measurements as simple means to inspect wetting states of Si nanopillar arrays
Minji Gwon (1), Sujung Kim (1), Eunsongyi Lee (1), Dong-Wook Kim (1), Jiaqi Li (2), Xiumei Xu (2), Chang Chen (2)
(1)Ewha Womans University (Korea), (2)IMEC (Belgium) We investigated optical spectral response of Si nanopillar (NP) arrays with different wetting states using optical simulations. Reflectance spectra of the NP arrays exhibited a clear distinction depending on the wetting state. Interference at the top and bottom of the NPs was found to determine the spectra of all the arrays at long wavelengths. The Mie resonance, as well as the interference, in the NPs should be taken into account to explain the short wavelength reflectance spectra.
Engineering of Three-Dimensional Chiroplasmon via Glancing Angle Deposition (GLAD) on rigid and flexible substrate
Junhong Deng, Jeff Lau, Fan Bai, Jack Ng, Zhifeng Huang
Hong Kong Baptist University (Hong Kong) The fabrication of Co- and Bi-axial two-turns silver nanospirals (AgNSs) will be presented with multiple handedness on sapphires. The structure is constituted by one turn AgNS and 1/3, 2/3 or 1 turn with another handedness fabricating by glancing angle deposition. Electric circular dichroism (ECD) of chiral plasmonic properties is studied in UV-visible range, and high amplitude of bisignate ECD signal is found in visible range, which the array of AgNSs on flexible substrates demonstrate a similar gigantic ECD.
Modal Analysis of Graphene Microtubes Utilizing a Two-Dimensional Vectorial Finite Element Method
Vasileios Salonikios, Stamatios Amanatiadis, Nikolaos Kantartzis, Traianos Yioultsis
Aristotle University of Thessaloniki (Greece) The propagation properties of the surface plasmon polariton waves on a graphene microtube are investigated in the present work. The effective index of various modes, supported on the microtube, is extracted by means of an accurate two-dimensional finite element modal solver that models graphene as a surface boundary condition. Moreover, the electric field distribution of the radial electric component is plotted for a specific frequency, revealing a remarkable behavior of the surface wave propagation.
DNA-Origami as a Template to Study Plasmon-Exciton Interactions
Mauricio Pilo-Pais, Eva-Maria Roller, Tim Liedl
Ludwig Maximilians Universitat (Germany) We use the DNA-Origami technique to study plasmon-exciton interactions. DNA-templates are used to position with nanometer precision metallic nanoparticles, permitting to tune the plasmon resonance to the one from the exciton. Furthermore, metallic colloids are preferred over lithographic alternatives due to lower radiative losses. For these reasons, DNA-Origami is an ideal candidate to rationally assemble plasmon-exciton nanostructures. As a proof of concept, we present plasmon-exciton interactions using Jaggregates, displaying spectral shifts even for resonances that are greatly mismatched.
Strong Coupling in Complexes of Aluminium Nanoantennas and J-aggregates, Emission and Polarization of Hybrid States
Elad Eizner, Ori Avayu, Ran Ditcovski, Tal Ellenbogen
Tel Aviv University (Israel) We show that aluminium is well suited for strong coupling experiments and enables formation of exciton-localized-surface-plasmons (X-LSPs) across the entire visible spectrum potentially down to the ultraviolate regime. Huge Rabi splitting of 400 meV and signatures of emission from X-LSPs states are observed. In addition, we show that the coupling of vacuum LSP fluctuations with the excitons can be polarized. The results open new possibilities to study hybrid states and to actively modify energy transition processes on the nanoscale.
Resonantly enhanced dynamical Casimir effect for surface plasmon polaritons
Vladimir Hizhnyakov, Ardi Loot, Shahabedin Azizabadi
University of Tartu (Estonia) Dynamical Casimir effect, emission of pairs of quanta of surface plasmon polaritons (SPPs) in a metal-dielectric interface placed in a resonator under laser excitation is considered. In this case the emission is strongly enhanced. A theory is proposed which takes the enhancement into account. It is found that if the amplitude of laser-induced oscillations of the optical length of SPPs coincides with their wavelength a resonant enhancement of the yield of the emission takes place.
Colorimetric monitoring of nanometer distance changes in DNA-templated plasmon rulers
Laurent Lermusiaux, Vincent Maillard, Sebastien Bidault
ESPCI ParisTech (France) Molecular rulers based on gold nanoparticle groupings translate nanometer distances in spectroscopic information. We demonstrate here that measuring the color of single plasmon rulers on a calibrated camera provides a quantitative estimation of interparticle distances with nanometer precision. This widefield measurement scheme allows us to differentiate plasmon rulers linked by two conformations of the same DNA template, opening exciting perspectives for the low-tech optical sensing of single biomolecules.
Heavily dye-doped polymers allow Tamm Optical States between a periodic structure and an excitonic organic layer
Sara Nunez Sanchez (1), Martin Lopez-Garcia (2), M. Murshidy (3), A. Abdel-Hady (4), M. Serry (4), Ali Adawi (5), Jonh Rarity (2), Ruth Oulton (2), William Barnes (1)
(1)University of Exeter (United Kingdom), (2)University of Bristol (United Kingdom), (3)Helwan University (Egypt), (4)The American University in Cairo (Egypt), (5)University of Hull (United Kingdom) Tamm Optical States at the interface of a truncated photonic crystal and an organic polymer have been obtained due to the metal-like optical properties of the heavily dye-doped polymer. The dispersion curves of these novel modes show two cut-off wavelengths controlled by the mismatch of the mode propagation and the high reflectance bandwidth. These results reveal the potential applications of materials doped with strongly interacting excitons in photonic structures through controlled photonic modes.