Tamm Plasmon Polaritons Research Articles

Two-Dimensional Dynamic Beam Steering by Tamm Plasmon Polariton

The dynamic steering of a beam reflected from a photonic structure supporting Tamm plasmon polariton is demonstrated. The phase and amplitude of the reflected wave are adjusted by modulating the refractive index of a transparent conductive oxide layer by applying a bias voltage. It is shown that the proposed design allows for two-dimensional beam steering by deflecting the light beam along the polar and azimuthal angles.

Hollow-core fiber sensor based on the long-range Tamm plasmon polariton with enhanced figure of merit

The potential of long-rang Tamm plasmon polariton (LRTPP) for sensing applications is theoretically investigated in a planar distributed Bragg reflector (DBR) structure containing a thin metal film. Results show that both sensitivity and figure of merit (FOM) increase with increasing incidence angle under transverse electric polarization. Due to the difficulty of achieving very large incidence angles in planar structures in practice, a LRTPP based hollow-core fiber (HF) sensor is proposed, where all transmitted lights in the fiber core have large incidence angle close to 90° on the inner surface of the HF. The ray transmission model is adopted to calculate the transmission spectra of the proposed HF LRTPP sensor. A comprehensive theoretical analysis about the influence of the structural parameters on the sensor performance is carried out, including the thickness of the metal layer and the number of periods of the DBRs. The HF LRTPP sensor achieves a sensitivity of 774 nm/RIU and FOM of 227.6 RIU−1 at the refractive index (RI) around 1.00 for gas sensing. In the RI range of 1.33–1.53, a sensitivity of 705 nm/RIU and FOM of 201.4 RIU−1 are achieved. The FOM of the HF LRTPP sensor is 2–7 times higher than that of the HF Tamm plasmon polariton (TPP) sensor, while the sensitivities are comparable. Benefiting from the lower attenuation and narrower resonance dip, the idea of utilizing LRTPP mode in DBR-metal-DBR structure to improve the sensor performance will provide a new way for the design of TPP sensors and promote the related researches.

Understanding the coupling between MIM cavities due to single and double Tamm plasmon polaritons

The interplay between light and matter plays a crucial role in various applications, ranging from sensor technologies to integrated optoelectronic architectures. In this contribution, a systematic numerical study is made over the symmetry role of the 1D photonic structures (PhSs) containing a low number of slabs embedded in thin metal layers, in order to find the adequate conditions to enhance the quality factor of resonances and energy confinement in the subwavelength scale. We show the existence of single and double Tamm plasmon polaritons (TPPs) states according to the symmetry of the PhS, which allow to tune weak and strong coupling regimes with Metal–Insulator–Metal (MIM) platforms combined in a unique MIM-PhS-MIM structure. We found that while weak coupling is observable between MIM and PhS states at the PhS cavity mode wavelengths, strong coupling among the 2 MIMs and the PhS is obtained only at the TPP resonance wavelengths, exhibited by anti-crossing splittings at adequate insulator thicknesses. We found that for the double Tamm plasmon polaritons, the energy splitting can reach up to 134 meV, unlike the single TPPs where the maximum energy splitting is on the order of 50 meV. The degree of coupling was explained by the implementation of a variational method that exploits the analogy the optical superlattice herein proposed and an analogous superlattice quantum well. This article shows that TPP resonances are responsible for the coherent coupling between the two MIMs placed at a long distance given by the PhSs. Thus, these platforms provide an interesting and experimentally accessible route for the coupling of emitters in optoelectronic devices.

Near-perfect multi-band graphene absorber with a compound grating-based resonant structure

We proposed a multi-band graphene absorber composed of a resonant compound grating (RCG), monolayer graphene, a thin silver layer, and a distributed Bragg reflector (DBR). A multi-band near-perfect absorption spectrum can be determined by three different physical mechanisms, including guided mode resonance (GMR), quasi-bound states in the continuum (quasi-BIC), and Tamm plasmon polaritons states (TPPs). Interestingly, the quasi-BIC mode can be achieved by changing grating layer spacing. In addition, the BIC mode can also be realized by varying grating periods. The variation of the absorption peak can be observed by changing the spacing layer thickness of the DBR structure, and the waveguide layer and grating layer thickness of the compound grating. Simulation results show that the absorption peaks of the three modes excited by our proposed absorbers are high as 80% at an incident light angle of 25°.

Graphene-Based Refractive Index Sensor With a 1-D Topological Photonic System

A terahertz refractive index sensor, which relies on utilizing the Tamm plasmon polariton and localized topological edge state, is proposed in a one-dimensional photonic crystal based on graphene. The proposed sensor structure is an active photonic device due to graphene’s tunable Fermi energy and optical properties. High sensitivity and a high figure of merit (FOM) are the results of the topological protection that allows a perfect zero reflection. Furthermore, the study investigates the sensing performance with various structural and material parameters. This refractive index sensor has the potential to be modified for use in industrial and diagnostic applications.

Theoretical optimization of Tamm plasmon polariton structure for pressure sensing applications

Theoretical optimization of Tamm plasmon polariton structure for pressure sensing applications

Spectral characterization of selective emission by an aperiodic cavity-enhanced Tamm plasmon-polariton emitter

We report highly selective resonant emission from an aperiodic Tamm plasmon-polariton (TP) emitter featuring a targeted mid infrared emission wavelength in the region of 4.26 μm. This spectral region is of high interest in context with integrated CO2 absorption sensing. To the best of our knowledge, the measured thermal emission at peak temperatures up to 500 °C of TP emitters featuring a half-wavelength cavity have never been related to simulations in a satisfactory manner in terms of peak position, emission intensity and temperature behavior. The layer thicknesses quantified via scanning electron microscope (SEM) featured deviations from the targeted periodic configuration due to statistical variation of deposition and etching process. Simulations using the Transfer-Matrix Method suggested a higher Q-factor and higher peak emission associated with the obtained aperiodic configurations compared to the target periodic configuration featuring a quarter-wave stack (QWS). Although the improved spectral features of the aperiodic stack could not quite be resolved, the spectral position, the qualitative temperature behavior and the angular emission pattern in the range of 0° to 10° could be confirmed by Fourier-transform infrared (FTIR) spectroscopy.

Tamm-plasmon-polariton biosensor based on one-dimensional topological photonic crystal

Tamm-plasmon-polariton (TPP) has strong light absorption and polarization-independence, shows potential application in the optical biosensors. However, with the weak field confinement of the distributed Bragg reflector (DBR), the sensitivity enhancement of TPP biosensors require defect layers or nano-materials with strong light absorption. Herein, we propose a novel TPP biosensor by using one-dimensional topological photonic crystal (1D TPhC) as DBR, the working wavelength is 633 nm, where 1D TPhC is composed by two 1D photonic crystals (1D PhCs) with different topological invariants. The strong field confinement of 1D TPhC is employed to improve the light absorption of TPP, and enhance the susceptibility of the biosensor to the analyte. Since TPP is polarization-independent, it has superior sensing performance in both transverse electric (TE) and transverse magnetic (TM) polarization modes. The sensitivity and Figure of Merit (FOM) are 2.6553 × 104 RIU−1 (1.3349 × 104 RIU−1) and 3.1238 × 107 RIU−1deg−1 (6.6745 × 108 RIU−1deg−1) for TM(TE)-polarization mode. The proposed TPP biosensor without defect layer, doesn’t need consider the thickness and position of the sensing medium layer, shows high operational flexibility. Besides, with the protection of the topological edge state, this biosensor has high tolerance to the thickness deviations, which can reduce the requirements on fabrication. It is anticipated that the proposed TPP biosensor has excellent sensing performances, possesses great potentials in environmental monitoring, biological detection, etc.

Coupled Tamm Phonon and Plasmon Polaritons for Designer Planar Multiresonance Absorbers.

Wavelength-selective absorbers (WS-absorbers) are of interest for various applications, including chemical sensing and light sources. Lithography-free fabrication of WS-absorbers can be realized via Tamm plasmon polaritons (TPPs) supported by distributed Bragg reflectors (DBRs) on plasmonic materials. While multifrequency and nearly arbitrary spectra can be realized with TPPs via inverse design algorithms, demanding and thick DBRs are required for high quality-factors (Q-factors) and/or multiband TPP-absorbers, increasing the cost and reducing fabrication error tolerance. Here, high Q-factor multiband absorption with limited DBR layers (3 layers) is experimentally demonstrated by Tamm hybrid polaritons (THPs) formed by coupling TPPs and Tamm phonon polaritons when modal frequencies are overlapped. Compared to the TPP component, the Q-factors of THPs are improved twofold, and the angular broadening is also reduced twofold, facilitating applications where narrow-band and nondispersive WS-absorbers are needed. Moreover, an open-source algorithm is developed to inversely design THP-absorbers consisting of anisotropic media and exemplify that the modal frequencies can be assigned to desirable positions. Furthermore, it is demonstrated that inversely designed THP-absorbers can realize same spectral resonances with fewer DBR layers than a TPP-absorber, thus reducing the fabrication complexity and enabling more cost-effective, lithography-free, wafer-scale WS-absorberss for applications such as free-space communications and gas sensing.

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.

Study of Terahertz Sensing Performance Based on Graphene-DBR Asymmetric Structure

Tamm plasmon polaritons have super strong field localization, and can be directly excited by TM or TE polarized light without dispersive devices, whose related technology has become one of the research hotspots nowadays. In view of this, in this paper, a terahertz sensor device based on double-dip detection of Tamm plasmon polaritons is designed. The device is asymmetric structure, which can excite two Tamm plasmon polaritons modes with the different intrinsic energies at the interface between two DBRs and graphene. Through the optimized simulation analysis of its terahertz sensing characteristics, the results show that the reflection spectrum under this structure has two dips at 0.9THz and 1.0THz respectively, and their full widths at half maxima of 0.0361THz and 0.0131THz are relatively narrow. Moreover, their sensitivities are 0.21THz/RIU and 0.41THz/RIU, and the figure of merit can reach up to 5.69RIU−1 and 31.33RIU−1, respectively. Therefore, this research is suitable for high sensitivity terahertz double-dip detection, and has important application prospect in terahertz devices.

Near-field manipulation of Tamm plasmon polaritons.

Tamm plasmon polaritons (TPPs) arise from electromagnetic resonant phenomena which appear at the interface between a metallic film and a distributed Bragg reflector. They differ from surface plasmon polaritons (SPPs), since TPPs possess both cavity mode properties and surface plasmon characteristics. In this paper, the propagation properties of TPPs are carefully investigated. With the aid of nanoantenna couplers, polarization-controlled TPP waves can propagate directionally. By combining nanoantenna couplers with Fresnel zone plates, asymmetric double focusing of TPP wave is observed. Moreover, radial unidirectional coupling of the TPP wave can be achieved when the nanoantenna couplers are arranged along a circular or a spiral shape, which shows superior focusing ability compared to a single circular or spiral groove since the electric field intensity at the focal point is 4 times larger. In comparison with SPPs, TPPs possess higher excitation efficiency and lower propagation loss. The numerical investigation shows that TPP waves have great potential in integrated photonics and on-chip devices.

Wavelength- and Angle-Selective Photodetectors Enabled by Graphene Hot Electrons with Tamm Plasmon Polaritons

Recently, two-dimensional materials have attracted attention owing to their special optical characteristics and miniaturization, with low thickness as well as extremely high responsivity. Additionally, Tamm plasmon polariton (TPP) resonance can be observed by combining a metal film and a one-dimensional (1D) photonic crystal (PC), where an electric field confinement is located at the metal-1D PC interface. In this study, a graphene layer combined with a TPP is proposed as a wavelength- and angle-selective photodetector. The graphene layer is located where the strong field confinement occurs, and the photocurrent response is significantly enhanced with increasing absorption by over four times (from 62.5 μA⋅W-1 to 271 μA⋅W-1 and undetected state to 330 μA⋅W-1 in two different samples). Moreover, the graphene-TPP photodetector has wavelength and angle selectivity, which can be applied in LiDAR detecting, sun sensors, laser beacon tracking, and navigational instruments in the future.

Module-Level Polaritonic Thermophotovoltaic Emitters via Hierarchical Sequential Learning.

Thermophotovoltaic (TPV) generators provide continuous and high-efficiency power output by utilizing local thermal emitters to convert energy from various sources to thermal radiation matching the bandgaps of photovoltaic cells. Lack of effective guidelines for thermal emission control at high temperatures, poor thermal stability, and limited fabrication scalability are the three key challenges for the practical deployment of TPV devices. Here we develop a hierarchical sequential-learning optimization framework and experimentally realize a 6″ module-scale polaritonic thermal emitter with bandwidth-controlled thermal emission as well as excellent thermal stability at 1473 K. The 300 nm bandwidth thermal emission is realized by a complex photon polariton based on the superposition of Tamm plasmon polariton and surface plasmon polariton. We experimentally achieve a spectral efficiency of 65.6% (wavelength range of 0.4-8 μm) with statistical deviation less than 4% over the 6″ emitter, demonstrating industrial-level reliability for module-scale TPV applications.

Wide-angle high-efficiency absorption of graphene empowered by an angle-insensitive Tamm plasmon polariton.

In recent years, researchers utilized Tamm plasmon polaritons (TPPs) in conventional heterostructures composed of a metal layer, a dielectric spacer layer and an all-dielectric one-dimensional (1-D) photonic crystal (PhC) to achieve high-efficiency absorption of graphene. According to the Bragg scattering theory, photonic bandgaps (PBGs) in all-dielectric 1-D PhC strongly shift toward shorter wavelengths (i.e., blueshift) as the incident angle increases. Therefore, TPPs in conventional heterostructures also show strongly blueshift property. Such strongly blueshift property of TPPs greatly limits the operating angle range of the high-efficiency absorption of graphene. Herein, we realize an angle-insensitive TPP in a heterostructure composed of a metal layer, a dielectric spacer layer and a 1-D PhC containing hyperbolic metamaterial layers. Empowered by the angle-insensitive property of the TPP, we achieve wide-angle high-efficiency absorption of graphene. The operating angle range (A > 80%) reaches 41.8 degrees, which is much larger than those in the reported works based on TPPs and defect modes. Our work provides a viable route to designing cloaking devices and photodetectors.

MXenes as Alternative Plasmonic Coatings on 1D Photonic Crystals Platforms for Tamm Plasmon Polaritons

New materials are of essential importance for the advancement of nanophotonics and nanoplasmonics. Numerous electromagnetic modes, especially various evanescent surface waves, prove themselves useful in multitudinous practical applications. Here we investigate the use of MXenes as alternative plasmonic materials in freestanding (substrateless) planar nanocomposites that support the existence of Tamm plasmon polaritons (TPP). We use finite element simulations to consider the influence of using MXenes on the propagation and distribution of TPP and the difference in their electromagnetic behavior compared to that of commonly used noble metals. While MXenes allow for somewhat weaker coupling between incident light and TPP, even the thinnest MXene layers practically completely screen the structure behind them. Our diffraction grating-enhanced stacks achieved incident light direction-dependent improvement of the coupling strength and polarization-dependent hybridization of electromagnetic states. MXene ensures improvements in functionality, especially spectral, directional, and polarization selectivity, by imparting rich modal behavior. Importantly, we observed high optical asymmetry of reflectance when illuminating the structures from opposite directions and obtained large high-to-low reflection ratios with a very small number of dielectric layers in the capping 1D photonic crystal. We conclude that MXenes represent a viable alternative for TPP-supporting structures, offering many advantages.

Tamm Plasmons in TiO2 Nanotube Photonic Crystals

The anodic TiO2 photonic crystals evoke great interest for application as photocatalytic media due to high absorption of light resuling from their specific structure. In this work, the optical properties of the photonic crystal based on a bamboo-type TiO2 nanotube with a metallic coating are analyzed theoretically by the finite-difference time-domain method. The occurrence of Tamm plasmons that appears as a peak in the absorption spectrum is predicted. A Tamm plasmon polariton is a localized state of light excited at the boundary of two highly reflective media, a metal and a Bragg reflector. The integral absorption of the gold-, titanium-, and titanium nitride-coated photonic crystals in the wavelength range of 450–600 nm is calculated. It is established that the titanium nitride-coated structure exhibits the maximum integral absorption.

A dual-band hydrogen sensor based on Tamm plasmon polaritons.

Optical hydrogen sensors possess significant potential in various fields, including aerospace and fuel cell applications, which is due to their compact design and immunity to electromagnetic interference. However, commonly used sensors mostly use single-band sensing, which increases the risk of inaccurate measurements due to environmental interference or operational errors. To address this issue, this study proposes a dual-band hydrogen sensor comprising a Pd metal layer, a dielectric spacer layer, a defect layer, and a photonic crystal. By leveraging the interaction between the defect mode in the excitonic microcavity structure and the Tamm plasmon polaritons (TPPs) and Fabry-Perot (FP) resonances, the structure simultaneously generates two near-zero resonance valleys in the visible wavelength range. By adjusting the thickness of the defect layer, the coupling effect of the defect mode and TPPs together with FP resonance respectively is optimized. When the thickness is 0.27 μm, the sensitivities of the Tamm resonance band and FP resonance band are 239 and 21 RIU-1, respectively. Compared with the common sensors with a single band, its low-sensitivity wavelength can be used as a reference to assist the high-sensitivity wavelength for sensing. In addition, we find that the proposed sensor, through calculation, has good fault tolerance for both the thickness of the defect layer and the incident light angle. This study demonstrates a dual-band hydrogen sensor with TPPs, which is important for exploring new optical hydrogen sensors.

Design of Refractive Index Sensor Based on Fabry-Perot Resonance Induced by Tamm Plasmon Polaritons

Design of Refractive Index Sensor Based on Fabry-Perot Resonance Induced by Tamm Plasmon Polaritons

Slow-light effects based on the tunable Fano resonance in a Tamm state coupled graphene surface plasmon system.

We theoretically realize the tunable Fano resonance in a hybrid structure that allows the coupling between Tamm plasmon-polaritons (TPPs) and graphene surface plasmon-polaritons (SPPs). In this coupling system, a distributed Bragg reflector (DBR)/Ag structure is designed to generate the TPP with a narrow resonance, and the graphene SPP is excited by grating coupling with a broad resonance. The overlap of these two kinds of resonances results in the Fano resonance with a high-quality factor close to 1500. The behaviors of the Fano resonance are discussed carefully, and the results show that both the graphene Fermi level and the incidence angle can actively tune the profile of the Fano resonance. Owing to the ultrasharp spectrum of the tunable Fano resonance, our design may offer an alternative strategy for developing various optoelectronic devices such as filters, sensors, and nonlinear and slow-light devices. Finally, as an example of the potential applications, we apply the tunable Fano resonance to the slow-light effect, a high performance slow-light effect can be achieved, and the group delay can reach up to 52 ps.