Graphene-based dual-band near-perfect absorption in Rabi splitting between topological edge and Fabry-Perot cavity modes

2021 ◽  
Author(s):  
Tongtong Wei ◽  
zengping su ◽  
yueke wang

Abstract We propose a graphene embedded one-dimensional (1D) topological photonic crystal heterostructure, where the strong coupling occurs between the topological edge mode (TEM) and the Fabry-Perot cavity mode (CM). It is shown that the strong coupling leads to the hybridization between TEM and CM, with a Rabi splitting. Based on finite element method (FEM), a dual-band near-perfect absorption, which can be actively tuned by the Fermi energy of the graphene and incident angle, is found in the Rabi splitting region. Theoretically, the TEM-CM coupling can be analyzed by the classic oscillator model. In particular, when the Fermi energy of graphene slightly increases around 0.4 eV, the dual-band near-perfect absorption shows a rapid decrease from one to zero, which offers a possible way for absorption optical switches.

2021 ◽  
Vol 9 ◽  
Author(s):  
Xuehan Liu ◽  
Keyang Li ◽  
Zhao Meng ◽  
Zhun Zhang ◽  
Zhongchao Wei

A subwavelength metamaterial perfect absorber (MPA) in optical communication band was proposed and tested using the finite-difference time-domain method. The absorber is periodic and comprises a top layer of diamond silicon surrounded by L-shaped silicon and a gold layer on the substrate. It can achieve dual-band perfect absorption, and one of the peaks is in the optical communication band. By changing the gap (g) between two adjacent pieces of L-shaped silicon, and the thickness (h) of the silicon layer, the resonance wavelength of absorption peak can be tuned. When the incident electromagnetic wave entered the absorber, the metamaterial absorber could almost completely consume the incident electromagnetic waves, thereby achieving more than 99% perfect absorption. The absorption peak reaches 99.986% at 1310 nm and 99.421% at 1550 nm. Moreover, the MPA exposed to different ambient refraction indexes can be applied as plasma sensors, and can achieve multi-channel absorption with high figure of merit (FOM*) value and refractive index (RI) sensitivity. The FOM* values at 1310 nm and 1550 nm are 6615 and 168, respectively, and both resonance peaks have highly RI sensitivity. The results confirm that the MPA is a dual-band, polarization-independent, wide-angle absorber and insensitive to incident angle. Thence it can be applied in the fields of optical communication, used as a light-wave filter and plasma sensor, and so on.


Plasmonics ◽  
2017 ◽  
Vol 13 (3) ◽  
pp. 803-809 ◽  
Author(s):  
Jipeng Wu ◽  
Jun Guo ◽  
Xi Wang ◽  
Leyong Jiang ◽  
Xiaoyu Dai ◽  
...  

Author(s):  
Hidefumi Hiura ◽  
Atef Shalabney ◽  
Jino George

<p>In conventional catalysis the reactants interact with specific sites of the catalyst in such a way that the reaction barrier is lowered and the reaction rate is accelerated. Here we take a radically different approach to catalysis by strongly coupling the vibrations of the reactants to the vacuum electromagnetic field of a cavity. To demonstrate the possibility of such cavity catalysis, we have studied hydrolysis reactions under strong coupling of the OH stretching mode of water to a Fabry-Pérot (FP) microfluidic cavity mode. This results in an exceptionally large Rabi splitting energy ℏΩ<sub>R</sub> of 92 meV (740 cm<sup>−1</sup>), indicating the system is in vibrational ultra-strong coupling (V-USC) regime and we have found that it enhances the hydrolysis reaction rate of cyanate ions by 10<sup>2</sup> times and that of ammonia borane by 10<sup>4</sup> times. This catalytic ability is shown to depend only upon the cavity tuning and the coupling ratio. Given the vital importance of water for life and human activities, we expect our finding not only offers an unconventional way of controlling chemical reactions by ultra-strong light-matter interactions, but also changes the landscape of chemistry in a fundamental way.</p>


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Qi Han ◽  
Lei Jin ◽  
Yongqi Fu ◽  
Weixing Yu

We report the broadband efficient light absorbing property of a structure of quadrangular frustum pyramid array in visible regime. The structure can absorb light efficiently with an average absorptivity of 0.98 over the whole visible waveband. In addition, it is found that this kind of super light absorbing can maintain an average of 0.9 for a wide incident angle range. The perfect absorbing property of the metamaterial-based nanoring array is attributed to the effect of the Fabry-Perot resonance. The structure is possible to be used as a type of Si photonics devices in future photonic circuits.


Author(s):  
Hidefumi Hiura ◽  
Atef Shalabney ◽  
Jino George

<p>In conventional catalysis the reactants interact with specific sites of the catalyst in such a way that the reaction barrier is lowered and the reaction rate is accelerated. Here we take a radically different approach to catalysis by strongly coupling the vibrations of the reactants to the vacuum electromagnetic field of a cavity. To demonstrate the possibility of such cavity catalysis, we have studied hydrolysis reactions under strong coupling of the OH stretching mode of water to a Fabry-Pérot (FP) microfluidic cavity mode. This results in an exceptionally large Rabi splitting energy ℏΩ<sub>R</sub> of 92 meV (740 cm<sup>−1</sup>), indicating the system is in vibrational ultra-strong coupling (V-USC) regime and we have found that it enhances the hydrolysis reaction rate of cyanate ions by 10<sup>2</sup> times and that of ammonia borane by 10<sup>4</sup> times. This catalytic ability is shown to depend only upon the cavity tuning and the coupling ratio. Given the vital importance of water for life and human activities, we expect our finding not only offers an unconventional way of controlling chemical reactions by ultra-strong light-matter interactions, but also changes the landscape of chemistry in a fundamental way.</p>


2019 ◽  
Author(s):  
Hidefumi Hiura ◽  
Atef Shalabney ◽  
Jino George

Water is of vital importance for life and human activities on Earth—it exhibits unique properties due to its interlinked and multipoint hydrogen bonding network. Here, we experimentally show that water can undergo vibrational ultra strong coupling (V-USC) in both the liquid and solid forms when the OH stretching mode of water or ice is resonantly coupled with an optical mode of an infrared Fabry−Pérot cavity. The light-coupled H<sub>2</sub>O under V-USC reveals the largest Rabi splitting ever reported, reaching 22% and 26% of the vibrational energy for water and ice, respectively. We confirm that the extraordinarily large Rabi splitting stems from the densely packed minuscule molecular structures, large vibrational energies, and broad and intense absorptions due to intermolecular hydrogen bonding. These new findings offer a brand-new platform in polaritonic chemistry for controlling the properties of water with an ultra strong light-matter interaction.


AIP Advances ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 085007 ◽  
Author(s):  
Alireza Ghaneizadeh ◽  
Khalil Mafinezhad ◽  
Mojtaba Joodaki

Author(s):  
Hidefumi Hiura ◽  
Atef Shalabney ◽  
Jino George

Water is of vital importance for life and human activities on Earth—it exhibits unique properties due to its interlinked and multipoint hydrogen bonding network. Here, we experimentally show that water can undergo vibrational ultra strong coupling (V-USC) in both the liquid and solid forms when the OH stretching mode of water or ice is resonantly coupled with an optical mode of an infrared Fabry−Pérot cavity. The light-coupled H<sub>2</sub>O under V-USC reveals the largest Rabi splitting ever reported, reaching 22% and 26% of the vibrational energy for water and ice, respectively. We confirm that the extraordinarily large Rabi splitting stems from the densely packed minuscule molecular structures, large vibrational energies, and broad and intense absorptions due to intermolecular hydrogen bonding. These new findings offer a brand-new platform in polaritonic chemistry for controlling the properties of water with an ultra strong light-matter interaction.


Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 352
Author(s):  
Abedin Nematpour ◽  
Maria Luisa Grilli ◽  
Laura Lancellotti ◽  
Nicola Lisi

Graphene is emerging as a promising material for the integration in the most common Si platform, capable to convey some of its unique properties to fabricate novel photonic and optoelectronic devices. For many real functions and devices however, graphene absorption is too low and must be enhanced. Among strategies, the use of an optical resonant cavity was recently proposed, and graphene absorption enhancement was demonstrated, both, by theoretical and experimental studies. This paper summarizes our recent progress in graphene absorption enhancement by means of Si/SiO2-based Fabry–Perot filters fabricated by radiofrequency sputtering. Simulations and experimental achievements carried out during more than two years of investigations are reported here, detailing the technical expedients that were necessary to increase the single layer CVD graphene absorption first to 39% and then up to 84%. Graphene absorption increased when an asymmetric Fabry–Perot filter was applied rather than a symmetric one, and a further absorption increase was obtained when graphene was embedded in a reflective rather than a transmissive Fabry–Perot filter. Moreover, the effect of the incident angle of the electromagnetic radiation and of the polarization of the light was investigated in the case of the optimized reflective Fabry–Perot filter. Experimental challenges and precautions to avoid evaporation or sputtering induced damage on the graphene layers are described as well, disclosing some experimental procedures that may help other researchers to embed graphene inside PVD grown materials with minimal alterations.


Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 488 ◽  
Author(s):  
Pinghui Wu ◽  
Congfen Zhang ◽  
Yijun Tang ◽  
Bin Liu ◽  
Li Lv

A simple metamaterial absorber is proposed to achieve near-perfect absorption in visible and near-infrared wavelengths. The absorber is composed of metal-dielectric-metal (MIM) three-layer structure. The materials of these three-layer structures are Au, SiO2, and Au. The top metal structure of the absorber is composed of hollow three-dimensional metal rings regularly arranged periodically. The results show that the high absorption efficiency at a specific wavelength is mainly due to the resonance of the Fabry–Perot effect (FP) in the intermediate layer of the dielectric medium, resulting in the resonance light being trapped in the middle layer, thus improving the absorption efficiency. The almost perfect multiband absorption, which is independent of polarization angle and insensitivity of incident angle, lends the absorber great application prospects for filtering and optoelectronics.


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