Tamm Structures Research Articles

Multiple hybrid Spp-Tamm modes in Ag grating/DBR microcavity

High confinement of surface plasmon polariton (SPP) have important applications in many aspects. However, access to high-Q resonant modes in metal cavity have many difficulties because of high Ohmic losses, large radiative losses and limited cavity designs. The Tamm mode is another surface plasmonic mode which has a high Q value but poor confinement. Here, we present a grating Tamm structure in which both nonradiative and radiative damping are suppressed, enabling excitation of high-Q and high confinement of hybrid SPP-Tamm mode. Theoretical analysis and simulations show that the proposed structure supports six resonance modes. By manipulating the geometric parameters of the metal grating, the multiple hybrid SPP-Tamm resonances could be well-defined and tuned with wavelength tuning sensitivity up to 1 nm. These results are promising for potential applications such as multiplexing, multi-frequency sensing and imaging.

Dual-band high quality-factor perfect absorber based on uniaxial/biaxial anisotropic van der Waals polar crystals

Phonon polaritons (PhPs) in two-dimensional van der Waals crystals, such as hexagonal boron nitride (hBN) and α-phase molybdenum trioxide (α-MoO3), exhibit remarkable spatial confinement and extremely low optical losses, offering possibilities for the development of novel micro and nanophotonic devices at mid-infrared wavelengths. Here, we demonstrate the potential of the proposed Tamm structure to achieve dual-band high quality-factor perfect absorption within the mid-infrared range. This structure utilizes upper and lower spacer layers to isolate the anisotropic materials hBN and α-MoO3 from one-dimensional photonic crystals, where the Tamm phonon polaritons (TPhPs) are respectively excited at the interfaces, facilitating strong coupling with incident light and leading to significant dual-band perfect absorption phenomena. The results demonstrate that due to polariton resonances, the absorption peaks exhibit extremely narrow absorption bandwidths, with the maximum quality-factor reaching up to 297. In addition, tunable resonant wavelengths and polarization-dependent absorption properties are also demonstrated in the proposed Tamm structure. This study provides an alternative and straightforward approach for constructing dynamic and multifunctional optical devices such as optical modulators, tunable multi-band filters and biosensors.

High Quality Near‐Infrared Single‐Mode Lasing from γ‐InSe Using a Transferrable Planar Microcavity

AbstractThe on‐chip near‐infrared (NIR) lasing devices based on van der Waals (vdW) layered materials are highly desired owing to their widespread applications in optoelectronic communication, computing, and sensing. However, the single‐mode NIR lasing devices with superior performance based on vdW layered materials are hard to obtain because of complex and meticulous microcavity structure and the damage to layered materials during preparation. Here, a high‐quality NIR single‐mode lasing device in γ‐phase indium selenide (γ‐InSe) is achieved by using a transferrable planar microcavity. The single‐mode lasing devices based on distributed Bragg reflectors microcavity and super Tamm structure can be simply prepared with quality factors up to 5710 and 3526, respectively. And angle‐resolved spectra show that the lasing device has high directionality with divergence angle <5°. Moreover, the wavelength of lasing device can be tuned ≈30 nm by varying the cavity length via thickness control of γ‐InSe layer. These results not only suggest that γ‐InSe is a promising material for NIR lasing devices, but also present a simple and effective approach for preparing high‐quality lasing devices utilizing other vdW layered materials.

Voltage tuning multi-photon processes with a graphene-based Tamm structure

Tamm plasmon modes are used to realize the modulation of multi-photon processes. Through effectively combining the rear-earth doped layer and a monolayer graphene in a Tamm structure, the emission of multi-photon processes can be tuned by the applied voltage. Results show that the proposed structure has a narrow absorption peak near 1550 nm, which is corresponding to the excitation source wavelength of the multi-photon processes. Importantly, the emission intensity of multi-photon processes can be tuned from 1 fold to ∼10.1 fold when we changed the applied voltage. Meanwhile, the emission color of the multi-photon processes can be tuned from yellow to green via adjusting the applied voltage. The proposed voltage tuning approach may be promoted to all kinds of nonlinear optical phenomenons, like Stimulated Raman Scattering, optical mixing and photorefractive effect.

Confined Tamm plasmon light-emitting diodes

In this Letter, we describe a fabrication process for current injection into micrometer-size Ag/GaAs Tamm emitting diodes. It requires a special care to minimize surface damages as the Tamm mode is localized very close to the surface. Electroluminescence from GaAs quantum wells is demonstrated at room temperature, with a dispersion that follows the Tamm mode. For small diameters Tamm structures, in-plane confinement leads to electroluminescence into discretized energy modes. The observation of electrically excited emission from a confined diode is an important step toward the development of Tamm plasmon optical devices with new functionalities.

Purcell and Collection Efficiency Enhancement of Single NV‐ Center Emission Coupled to an Asymmetric Tamm Structure

AbstractThe resonant modes associated with engineered photonic structures of different spatial‐dimension are essential to obtain bright on‐demand single photon sources for quantum technologies. Negatively‐charged nitrogen‐vacancy (NV‐) center in diamond is proposed as an excellent single‐photon source at room temperature. The possible optical readout of spin states in diamond makes it a good candidate for the spin‐photon interface. However, poor light collection, feeble zero‐phonon line, low emission rate, and broad phonon‐induced emission limit the use of NV‐ centers in quantum technologies. Here, a feasible, easy‐to‐fabricate, asymmetric Tamm structure coupled with a single NV‐ center to enhance the emission rate of zero phonon line (ZPL) with better light collection efficiency is presented. The asymmetric Tamm structure shows dual resonant mode with one of the modes coinciding with NV‐ ZPL wavelength of 640 nm. The mode quality factor (Q‐factor) is 140, which is greater than the Q‐factor of conventional Tamm structure and hence, improved field intensity localization. The authors achieved four times Purcell enhancement and five times enhanced light collection efficiency at 640 nm. The proposed asymmetric Tamm structure helps to generate bright single photons using NV‐ center and improves the efficacy of the spin‐photon interface.

Refractive index sensing based on surface plasmon-coupled emission excited by reverse Kretschmann or Tamm structure.

Surface plasmon coupled emission (SPCE) is the directional emission of surface plasmon polaritons (SPPs) through the reverse channels of focused surface plasmon excitation to the far field, which has shown significant possibilities in bioanalysis, medical diagnosis, and so on. We carried out a theoretical study of SPCE to analyze its mechanisms and proposed a new structure to improve the emission intensity of SPCE. We proposed a method for refractive index sensing based on SPCE, consisting of a reverse Kretschmann (RK) or a Tamm structure for the first time, to the best of our knowledge. The corresponding sensing sensitivity reaches 87.61 deg/RIU and 67.44 deg/RIU, respectively. Compared with that in the RK, the far-field radiation intensity of SPCE in the Tamm structure is enhanced by two orders of magnitude. Furthermore, compared with surface plasmon resonance (SPR) sensing, SPCE sensing can improve the signal-to-noise ratio (SNR) and excitation efficiency. Our structures enable refractive index sensing with a high SNR, high spatial resolution, and without the requirement of angular alignment using complex mechanics, which are suitable for practical applications such as quantitative biomolecular detection and medical diagnosis.

Tamm plasmon-polaritons and Fabry-Perot excitation in a magnetophotonic structure

A magnetophotonic Tamm structure with a bilayer film of Bi-substituted iron garnets (Bi:IG) with a significant magneto-optical (MO) response, placed in microcavity, and Tamm plasmon-polaritons (TPP) excited at the interface of the Au layer, were proposed. Optical and MO spectra of the hybrid state were investigated theoretically and experimentally in Faraday effect geometry at a normal incidence of the light wave. Anticrossing behavior of the TPP and Fabry-Perot resonances and dependence of spectral splitting on their hybrid state on the thickness of the Au layer was shown. By varying the thickness of the top SiO2 layer in the structure, the modifications of spectra on the TPP spectral position were described in detail. The results can be used to design tunable MO devices and sensors.

High-sensitivity multi-channel refractive-index sensor based on a graphene-based hybrid Tamm plasmonic structure

In this paper, we propose a high-performance refractive-index sensor at a near-infrared band based on a hybrid Tamm structure. The optical properties of this graphene-based hybrid Tamm plasmonic structure are analyzed and investigated by using the transfer matrix method (TMM). Due to the excitation of the guide mode resonance (GMR) and Tamm plasmon polariton (TPP) resonance, the structure can realize multi-channel perfect absorption. This structure can be utilized as a refractive index sensor because the position of the absorption peak is sensitive to the refractive index of the ambient layer. Therefore, we obtain the sensitivity to 950 nm per refractive index unit (nm/RIU) and figure of merit (FoM) of 161 RIU-1 after studying the performance under different structural parameters. We believe that the proposed configuration is expected to be used to manufacture high-performance biosensors or gas sensor devices and other related applications in the near-infrared band.

High-performance terahertz refractive index sensor based on a hybrid graphene Tamm structure

In recent years, the research on tunable and high-performance terahertz devices has attracted widespread attention. In this paper, we propose a novel refractive index sensor consisting of monolayer graphene and multilayer photonic crystal with a defect layer. It is found that Tamm plasmon polaritons can be excited at the top graphene interface, which can strongly interact with the defect mode in this coupled structure. The results of numerical simulation demonstrate that the coupling can be either tuned by adjusting the geometric parameters or actively controlled by the chemical potential in graphene as well as the incident angle of light, allowing for tunable dual-band perfect absorption with strong interaction. Moreover, the resonance frequency of the defect mode is sensitive to the changes of the ambient refractive index. The sensitivity and figure of merit of this device as a sensor can reach 1.01 THz per refractive index unit (THz/RIU) and 631.2 R I U − 1 , respectively. In addition to high performance, the sensor does not require phase- or polarization-matching devices, paving the way for the research of optical devices.

Refractive index sensor based on a Tamm Fabry-Perot hybrid resonance.

A highly sensitive refractive index sensor is proposed by using the resonant coupling of a Tamm state to a Fabry-Perot resonance in slits periodically pierced in a metal film. This new hybrid resonance exists at the interface between a dielectric Bragg mirror and a subwavelength metal grating. Contrary to a classic Tamm plasmon, it is sensitive to the ambient media refractive index due to its confinement inside the grating slits. The proposed sensor output can be either the reflected intensity or preferably the wavelength, and its sensitivity and figure of merit are numerically investigated with the help of rigorous coupled wave analysis. The sensitivity of the studied sensor is 87 nm/RIU for a refractive index range from 1.25 to 1.38, and, at the expense of the resolution, it can reach up to 160 nm/RIU for a grating duty cycle of 50%. The figure of merit is around ${{7.5}}\;{{\rm{RIU}}^{- 1}}$ with a large measuring range. The index sensor performances and operating resonance wavelength can be modified by adjusting the grating geometric parameters (height and duty cycle). The possibility to achieve wavelength modulation in any spectral range makes the proposed grating Tamm structure an attractive candidate to design refractive index sensors and photonic components in the infrared and terahertz domains.

Vibrational strong coupling between Tamm phonon polaritons and organic molecules

Phonon polaritons (PhPs) have a long lifetime and high confinement of light fields compared with their plasmonic counterparts in the mid-infrared range. Thus, PhPs are promising candidates for realizing vibrational strong coupling (VSC) with molecules. However, VSCs of PhPs in nanoresonators and thin films require the near-field technique and are limited to the transverse magnetic mode. Here we propose a new configuration based on the Tamm structure, which supports PhPs excited by the free-space incident light in both transverse-electric and transverse-magnetic modes. The VSC of a 300 nm thick molecular layer can be achieved with 21 c m − 1 Rabi splitting, according to the numerically obtained angle resolved reflectivity spectra with the transfer matrix method. Our findings provide a promising platform for applications in free-space sensing of vibrational modes and control of chemical reactions in compact devices.

Room-Temperature Lasing in a Low-Loss Tamm Plasmon Cavity

Optical Tamm structures offer great possibilities for the development of new optoelectronic devices ranging from polarized laser sources to plasmon generators. Indeed, thanks to the patterning of a...

Black phosphorus terahertz sensing based on photonic spin Hall effect.

A novel terahertz (THz) sensing scheme is proposed based on the photonic spin Hall effect (PSHE). By illumining a paraxial Gaussian THz beam onto a black phosphorus (BP)-based Tamm structure, the reflected beam will undergo in-plane spin splitting, i.e., the centroids of two opposite spin components separate spatially. Due to Tamm plasmon resonance, one of the spin components is very sensitive to the refractive index changes of the analyte layer sandwiched by monolayer BP and distributed Bragg reflector. The sensitivity of the spin-dependent shift can be up to 2804 mm/RIU with a refractive index resolution of ∼10-8 RIU. The sensitivity and dynamic sensing region can be flexibly tuned by the BP rotation angle, thickness of analyte layer, or operation frequency. Therefore, the proposed PSHE-based THz sensing provides a new avenue for the development of high-performance THz sensors; thus, we may find applications in chemical sensing and biosensing.

Spontaneous Emission Amplification in Silver—Organic Periodic Structures and Tamm Plasmon Structures

We have investigated Tamm plasmon structure and periodic metal-dielectric structures with active organic CBP (N,N-dicarbazolyl-4,4-biphenyl) layer. Tamm structure is based on SiO2/TiO2 5 pairs DBR, with 26 nm CBP and 50 nm silver layer on the top of it. Two periodic silver-organic structures using thermal evaporation technique with different CBP layer thickness (15 and 30 nm) was fabricated. The rate of fluorescence intensity decay of Tamm plasmon and periodic structures was experimentally measured in near ultraviolet region. We demonstrate, that decay time of CBP fluorescence intensity in Tamm plasmon structure and periodic metal-organic structures decreases several times.

Purcell effect investigation in organic Tamm plasmon structures

We provide a theoretical and experimental investigation of a Purcell enhancement in a Tamm-plasmon based microcavity structure with an organic (4,4′-Bis(N-carbazolyl)−l,l′- biphenyl (CBP)) active layer. The microcavity structure was fabricated using several techniques as a magnetron deposition (Ta2O5/SiO2 dielectric Bragg mirror) and a thermal evaporation (CBP organic layer and silver layer on the top). Dependency of the modal Purcell factor on emission angle and frequency was calculated using S-quantization formalism. The emission spectra and the rate of fluorescence intensity decay of the Tamm structure was experimentally measured in ultraviolet region. We show, that at the frequencies corresponded to the Tamm plasmon resonance, the rate of the CBP molecule fluorescence decay increasing. Maximum registered value of the Purcell factor is close to 3.

Optical Tamm state aided room-temperature amplified spontaneous emission from carbon quantum dots embedded one-dimensional photonic crystals

Optical Tamm state (OTS) aided room-temperature amplified spontaneous emission (ASE) from carbon quantum dots (CQDs) embedded all-dielectric one-dimensional photonic crystals (1DPhCs) is presented. 1DPhCs, constituting twelve pairs of alternating quarter wave thick SiO2 and TiO2 thin films are fabricated by sol-gel synthesis route. The 1DPhCs are covered with ~50 nm thick silver thin film to obtain the Tamm structures. CQDs are prepared using organic precursors (onion pulp) and incorporated in the TiO2 matrix of the final four pairs of the 1DPhCs. OTSs are observed in the reflection spectra at a detection angle of ~15°, at ~648 nm and ~618 nm, for the samples with and without CQDs respectively. Comparisons of enhancement of photoluminescence from samples with and without CQDs are presented. ASE at ~648 nm corresponding to the OTS of the CQDs incorporated Tamm structure, and suppression of emission within the photonic stop-band is demonstrated.

Tamm plasmon-polaritons in a metal coated porous silicon photonic crystal

We report the realization of a Tamm plasmon resonance in a planar structure by deposition of a gold film on a one-dimensional photonic crystal made of mesoporous silicon. The observation of a dip in the reflectance as well as a singularity in the ellipsometric angles confirms the presence of Tamm plasmon-polaritons with a higher quality factor than previously reported for porous Tamm structures. The simple electrochemical fabrication process of the porous silicon multilayer has the potential to facilitate the advent of integrated Tamm sensors by allowing an analyte to diffuse to the region where the electromagnetic field enhancement is highest while being low-cost and potentially CMOS-compatible.

Perfect absorption of modified-molybdenum-disulfide-based Tamm plasmonic structures

The two-dimensional semiconductor materials of transition metal molybdenum disulfide display various special optical properties in the interaction of matter and light. In this work, we study the strong coupling between the two-dimensional materials’ excitons and Tamm plasmon polaritons (TPPs). To enhance the interaction between light and matter, we introduce the grating modulation in the traditional Tamm structure. By adjusting the structure parameters of the grating-modified Tamm system, we achieve perfect absorption in the visible region. Our research results will pave the way for the application of ultrathin polarization optical devices.

Sensitive singular-phase optical detection without phase measurements with Tamm plasmons

Spectrally-tailored interactions of light with material interfaces offer many exciting applications in sensing, photo-detection, and optical energy conversion. In particular, complete suppression of light reflectance at select frequencies accompanied by sharp phase variations in the reflected signal forms the basis for the development of ultra-sensitive singular-phase optical detection schemes such as Brewster and surface plasmon interferometry. However, both the Brewster effect and surface-plasmon-mediated absorption on planar interfaces are limited to one polarization of the incident light and oblique excitation angles, and may have limited bandwidth dictated by the material dielectric index and plasma frequency. To alleviate these limitations, we design narrow-band super-absorbers composed of plasmonic materials embedded into dielectric photonic nanostructures with topologically-protected interfacial Tamm plasmon states. These structures have planar geometry and do not require nanopatterning to achieve perfect absorption of both polarizations of the incident light in a wide range of incident angles, including the normal incidence. Their absorption lines are tunable across a very broad spectral range via engineering of the photon bandstructure of the dielectric photonic nanostructures to achieve reversal of the geometrical phase across the interface with the plasmonic absorber. We outline the design strategy to achieve perfect absorptance in Tamm structures with dissipative losses via conjugate impedance matching. We further demonstrate via modeling how these structures can be engineered to support sharp asymmetric amplitude resonances, which can be used to improve the sensitivity of optical sensors in the amplitude-only detection scheme that does not require use of bulky and expensive ellipsometry equipment.