Tamm Plasmon-polariton Mode Research Articles

High performance tri-band terahertz refractive index sensor based on cavity resonance and Tamm plasmonic modes

In this paper, a novel terahertz refractive index sensor consisting of two asymmetric distributed Bragg reflectors (DBRs) attached to graphene in the cavity, is proposed. Based on finite difference time domain simulation, Tamm plasmon polariton mode excited at the interface between the DBR and the graphene is coupled with the resonance modes of the cavity, which helps to improve the sensing performance. In its reflection spectra, there are three dips with the bandwidths of 1.82, 3.95 and 3.86 GHz at 1.04 THz, 3.00 THz and 3.13 THz after simulation optimization. And the corresponding sensitivities and the figure of merit can achieve 1.02, 2.58, 3.00 THz/RIU, and 559.34, 652.15, 776.17 RIU−1, respectively. Due to its high sensing performance and simple structure, the tri-band sensor may pave the way for the research on the detection of multimodal microscale analytes.

Design of a Highly Sensitive Self-Reference Tamm-Plasmon-Polariton Sensor Employing Ti3C2Tx MXene

This paper presents design and analysis of a self-reference refractive index sensor for precise detection of different concentrations of H5N1 virus in poultry. The sensor is based on the study of Tamm plasmon polariton (TPP) modes excited between Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Tx MXene and cavity layer integrated 1D photonic crystal (PhC). We demonstrate the self-reference characteristics of the sensor, which significantly decreases the error contributions by the environmental factors like the light intensity fluctuations and local temperature variations. The transfer matrix method (TMM) is employed to investigate the reflectance and absorbance of the sensor. The cornerstone of this work lies on the assay of the shift in the wavelength and intensity of the TPP mode vis-à-vis different concentrations of the H5N1 virus. Numerous structural parameters like selection of materials, thickness of the MXene layer, thickness of the cavity layer, and period of the PhC are judiciously optimized to envisage maximum sensing performance. The colormap plot of field distribution infers a strong electric field localization in the cavity layer, which indicates high absorption of TPP modes. Compared to the traditional TPP sensor designed with Ag thin film, the electric field intensity (EFI) and sensitivity of the proposed MXene-based TPP sensor have been boosted by 40% and 15.93% respectively. It is appraised that the proposed sensor delivers a maximum sensitivity of 60.9375 nm/HAU, quality factor of 5485.71, and detection limit of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${2.6}\times {{10}}^{-{6}}$ </tex-math></inline-formula> RIU. The proposed sensor can find suitable applications in the field of biomedical diagnostics, healthcare, food safety, and environmental monitoring.

Titanium nitride as a plasmonic material for excitation of Tamm plasmon states in visible and near-infrared region

In this study, I demonstrated the existence of Tamm plasmon polariton (TPP) modes at the interface of one-dimensional photonic crystals (1D PhC) and metal nitrides. Metal nitrides such as titanium nitride (TiN), zirconium nitride (ZrN), tantalum nitride (TaN), and hafnium nitride (HfN) exhibit metallic properties in the visible and infrared spectral ranges. Theoretical calculations were performed to evaluate TiN as an alternative plasmonic material to conventional plasmonic metals for the excitation of TPP modes in the visible and near-infrared spectral region. The transfer matrix method was used to study the proposed structure and its spectral properties. I also explored the suitable conditions for the efficient excitation of TPP modes with TiN as a plasmonic material. The optimum TiN thickness was investigated for TPP excitation in the visible and near-infrared spectral region. In addition, I explored the angular dispersion characteristics of the TPP modes in TiN-PhC configurations. The results obtained in this study may be useful for designing devices based on TPPs.

Dual-channel sensor based on Tamm plasmon polariton and defect mode hybridization in topological insulator covered photonic crystals

In this paper, a novel multi-channel refractive index sensor is proposed. The strong coupling between Tamm plasmon polariton (TPP) and defect modes of one-dimensional photonic crystals (1D-PCs) is used to design a high sensitivity sensor. The TPP is formed by topological insulators B i 1.5 S b 0.5 T e 1.8 S e 1.2 (BSTS) and 1D-PC. Within the 1D-PC, localized phase shifts are induced to form defect modes that can be hybridized with the TPP mode. More resonances can be formed by introducing additional defects in the 1D-PC. The proposed sensor provides great potential in the fields of multi-channel and multi-parameter sensing.

Near singular-phase optical biosensing with strongly coupled modes of a plasmonic–photonic trimer

A lithography-free plasmonic–photonic hybrid nanostructure exhibiting an interesting phenomenon of cavity-mediated normal-mode splitting among doubly-degenerate Tamm plasmon polariton modes has been designed and optimized to manifest three strongly coupled modes. The exotic dispersion of these supermodes is used to design a self-referenced spectroscopic refractive index sensor at optical frequencies with a substantial sensitivity value of 1410 nm RIU−1. The same structure is also shown to function as a singular-phase-based refractometric biosensing platform with multiple near-singular points, exhibiting a maximum sensitivity of around 27 000∘ RIU−1 with a sufficiently broad dynamic range of operation. Furthermore, the presence of three near-singular points provides the necessary flexibility in striking an appropriate balance between sensitivity and dynamic range of operation. The concomitant existence of the mentioned functionalities is an outcome of the strong coupling between the modes, which enables us to exhibit exquisite control over the dispersion of the supermodes. These distinctions enable our proposal to be of direct utility in highly demanding point-of-care biosensing applications.

Opto-electromagnetic Responses of Tamm Plasmon Polariton Modes in a Symbiotic Dual-Metallic architecture

We report a Tamm plasmon polariton (TPP) arrangement whose design consists of a thin Silver (Ag) film which is the plasmon-active metal and lies adjacent to the distributed Bragg Reflector (DBR) structure. The DBR consists of periodically stratified layers of Ta2O5 and SiO2. TPP modes are excited through normal incidence using a white light source and we have obtained the corresponding reflectivity spectrum as a function of wavelength. The excitation spectrum is characterized by a sharp and distinguishable reflectivity dip within the photonic band-gap of DBR. Extending this version of the idea, we have replaced the single plasmon-active metal by two metals to overrule the drawbacks of these single metals concerning their physiochemical properties like propagation length, chemical stability, and various losses during propagation of the plasmon wave, etc. Hence, we have obtained the reflectivity characteristics for different bimetallic architecture supporting TPP resonances. Thereafter, we have also obtained the Full Width at Half Minimum (FWHM) wavelengths and Quality Factor (Q-Factor) characteristics as a function of metal thickness for two different plasmon active metallic combinations, where the total bimetallic thickness remains constant. The shortcomings of a particular metal are nullified by the presence of the other metal with it. Such an arrangement is envisioned for the fabrication of nanoscale smart devices like optical and biosensors having potential applications in social welfare domain like monitoring the levels of food adulteration and food safety, etc.

Tamm-plasmon resonance based temperature sensor in a Ta2O5/SiO2 based distributed Bragg reflector

We demonstrate a Tamm-plasmon-polariton (TPP) based sensor for accurate determination of temperature. The sensing architecture is comprised of thin silver (Ag) film on a distributed-Bragg-reflector (DBR) structure made of periodically stratified multilayers of Ta2O5 and SiO2. TPP mode is excited using direct incidence of white-light-source at normal incidence as well as oblique incidence. The mode excitation is characterized by a sharp reflectivity minimum within the photonic bandgap (PBG) of DBR. It was observed that the depth of TPP resonance reduces uniformly as a function of temperature without affecting its sharpness. Defining temperature sensitivity in terms of change in reflectivity from the composite structure, a sensitivity of 7.8×10−4/°C is estimated for the sensing geometry. Also, the metallo-dielectric geometry supporting TPP modes is modeled using transfer-matrix-method for ascertaining the salient features of TPP modes which have a direct impact on sensing properties.

One-dimensional photonic crystals with highly Bi-substituted iron garnet defect in reflection polar geometry

It is represented the results of modelling of magnetooptical properties in reflection polar geometry of one-dimensional photonic crystal, in which highly Bi-substituted iron garnet defect of composition Bi1.0Y0.5Gd1.5Fe4.2Al0.8O12 / Bi2.8Y0.2Fe5Oi2 is located between the dielectric Bragg mirrors (SiO2 / TiO2)m (were m is number of layer pairs) and buffer SiO2 and gold top layers of different thicknesses is placed on structure. The modification of spectral line- shapes of microcavity and Tamm plasmon-polariton modes depending on m is found.

Hybrid Tamm plasmon-polariton/microcavity modes for white top-emitting organic light-emitting devices

White top-emitting organic light-emitting devices (WTOLEDs), emitting white light through a transparent top metallic electrode, have emerged as promising candidates as energy-efficient solid-state lighting sources and full-color flat-panel displays. The microcavity effect due to usage of metallic electrodes results in emission enhancement solely at a particular color, and therefore sets an obstacle for WTOLEDs, where at least two colors with balanced intensity should be emitted. Current efforts solving the problem basically rely on the relaxation of the microcavity effect, resulting in sacrificed light outcoupling efficiency in the original resonance region. Here, we demonstrate that by integrating a photonic crystal structure upon the top metallic electrode, an additional emission enhancement peak other than the one determined by the microcavity resonance could be provided by the Tamm plasmon-polariton mode. Mode hybridization induced dual hybrid modes with comparable light outcoupling efficiency can then be excited, from which two colors with balanced intensity could be emitted. Both experimental and theoretical results demonstrate that the proposed mode hybridization strategy may pave the way for the realization of WTOELDs towards high white color quality, improved viewing characteristics, and electroluminescence efficiency.

Second-harmonic generation enhancement in the presence of Tamm plasmon-polaritons.

Resonant enhancement of second-harmonic generation (SHG) intensity from a thin metal film is demonstrated in a Tamm plasmon-polariton mode excited at a metal/photonic crystal interface using nonlinear spectroscopy. Nonlinear effects enhancement in proposed structures exhibit strong polarization dependence (1:200 for the orthogonal fundamental polarizations). SHG enhancement factor evinces considerable angular dependence, rising from 50 for the 45° angle of incidence to 170 for the 10° angle of incidence. The results are analyzed numerically using a nonlinear transfer matrix technique. The findings elucidate the potential of Tamm plasmon-polaritons in the nonlinear optical applications.

On the performance of Tamm-plasmon and surface-plasmon hybrid-mode refractive-index sensor in metallo-dielectric heterostructure configuration

Hybrid modes formed as a consequence of coupling between Tamm-plasmon polariton (TPP) mode and surface plasmon polariton (SPP) mode in a metallo-dielectric heterostructure geometry exhibit interesting dispersive features which can be employed for realizing highly sensitive and accurate surface-plasmon-resonance (SPR) sensor. The transverse magnetically (TM) polarized TPP modes (TM-TPP), formed at the interface of distributed-Bragg reflector (DBR) and metal, are strongly dispersive as compared to SPP modes at optical frequencies that forms the basis of narrow interaction bandwidth which, in turn, results in improved accuracy of sensing. By deploying a nano/micro-fabrication compatible TiO2/SiO2-based DBR architecture in combination with different plasmon-active metals such as gold (Au), silver (Ag) and aluminum (Al), we propose a TM-TPP and SPP hybrid-mode sensor which exhibit high sensitivity ≥900nm/RIU for analyte refractive indices varying between 1.330 and 1.345. The investigation also revealed that the hybrid-mode sensor is most accurate in case of Al-based configuration amongst Au, Ag and Al which is primarily due to weaker dispersion characteristics exhibited by Al at visible frequencies. Since, the dispersive behavior of TM-TPP modes could be tailored appropriately in any spectral band, the sensing configuration could be immensely useful for designing sensors at those wavelength where optical sources are readily available.

Guided-Mode Analysis of Tamm-Plasmon Polariton at Metal–Heterostructure Dielectric Interface

We present a comprehensive analysis for transverse electric (TE) and transverse magnetic (TM) polarized guided Tamm-plasmon polariton (TPP) mode at metal-heterostructure media interface. We explicitly show that the quarter-wavelength stack condition will not be satisfied for TE or TM polarized TPP mode due to the existence of null-point at metal-heterostructure media boundary. Therefore, we propose an alternate route to design TPP waveguide by solving the mode-dispersion relation for different geometrical parameters in a TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> bilayer system. The guided TPP-modes (TE and TM) exhibit interesting dispersion characteristics which can be tailored as per the desired application. The group index of TM polarized TPP mode remains constant over a significant wavelength range which results into zero group-velocity dispersion (GVD) at λ ≈ 630 nm wavelength. Also, the propagation length for TM-polarized TPP modes vary between 25 μm to 50 μm in a 630-650 nm wavelength range. However, the variation of GVD for TE-modes exhibit a monotonic variation with an exceptionally large GVD ≈ -3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> ps/km·nm around λ = 632.8 nm.

Lasing of Tamm states in highly efficient organic devices based on small-molecule organic semiconductors.

We discuss approaches to increase the light outcoupling efficiency in organic microcavity (MC) lasers and organic light-emitting diodes (OLEDs). We find that the introduction of metals into the cavities leads to additional Tamm-plasmon polariton modes, while the corrugation of metal contacts, such as perforated μ-size holes or a periodic array of metal stripes, leads to 2D confinement of the cavity modes, which in turn reduces the lasing threshold in MCs. Furthermore, we elucidate light loss mechanisms in OLEDs and reveal how external dielectric layers and periodic gratings can be used to enhance outcoupling from the OLED cavity.

Direct excitation of the Tamm plasmon-polaritons on a dielectric Bragg reflector coated with a metal film

AbstractTamm plasmon-polariton is a surface state or surface wave formed at the boundary between a metal and a dielectric Bragg reflector. In order to directly excite the Tamm plasmon-polaritons with unit transmission, we design a structure of Bragg reflector coated with a metal film. Through the Bloch theorem of periodic structures and transfer matrix method, we deduce the existence conditions of the Tamm plasmon-polaritons. For a a finite structure, the Tamm plasmon-polaritons can be excited, which is dependent on the thickness of metal, the period number of the Bragg reflector, the incident direction and frequency. On proper conditions, a perfect transmission for the Tamm plasmon-polariton mode can be achieved without the use of attenuated total reflection prism coupling or diffraction grating.

Comparing resonant photon tunneling via cavity modes and Tamm plasmon polariton modes in metal-coated Bragg mirrors

Resonant photon tunneling was investigated experimentally in multilayer structures containing a high-contrast (TiO(2)/SiO(2)) Bragg mirror capped with a semitransparent gold film. Transmission via a fundamental cavity resonance was compared with transmission via the Tamm plasmon polariton resonance that appears at the interface between a metal film and a one-dimensional photonic bandgap structure. The Tamm-plasmon-mediated transmission exhibits a smaller dependence on the angle and polarization of the incident light for similar values of peak transmission, resonance wavelength, and finesse. Implications for transparent electrical contacts based on resonant tunneling structures are discussed.