scholarly journals Perfect absorption in free-standing GaAs nanocylinder arrays by degenerate critical coupling

2021 ◽  
Vol 121 ◽  
pp. 111558
Author(s):  
Wenya Chen ◽  
Xing Wang ◽  
Junyi Duan ◽  
Chaobiao Zhou ◽  
Tingting Liu ◽  
...  
Keyword(s):  
Critical Coupling ◽  
Free Standing ◽  
Perfect Absorption

scholarly journals Dual-guiding-layer resonance structure with an embedded metasurface for quasi-critical coupling without a perfect mirror

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gyeong Cheol Park ◽  
Kwangwook Park
Keyword(s):  
Refractive Index ◽  
High Refractive Index ◽  
Decay Rates ◽  
Single Layer Graphene ◽  
Resonance Structure ◽  
Critical Coupling ◽  
Coupling Condition ◽  
Perfect Absorption ◽  
High Background ◽  
Absorbing Material

Abstract We propose an all-dielectric quasi-one-port resonance structure that achieves near perfect absorption without the use of a back mirror. The structure mainly consists of a high-refractive-index silicon metasurface and surrounding high-refractive-index guiding layers. The dual-guiding-layer (DGL) structure has high background reflectance and is designed to have a ratio of two decay rates into the upper and lower regions within a wider range. When an absorbing material is introduced into a DGL system, it can be designed to achieve a near critical-coupling condition by reducing the constraints in the two decay rates. By using single-layer graphene as an absorbing material, the DGL resonance structure shows an absorption of ~ 97% and a phase change of ∼ 0.95π near the wavelength of 1550 nm, confirming quasi-critical coupling. The optimized DGL structure is relatively insensitive to potential fabrication imperfections, and consequently, the expected average peak wavelength and absorption are obtained as 1549.29 nm and 96.74%, respectively. Angle-dependent absorption confirms that maximum absorption occurs under normal incidence. The DGL absorber is also designed to cover the whole C-band region, in order to meet the quasi-critical-coupling condition. All mode profiles are similarly quasi-symmetric along the metasurface due to the same DGL resonance mechanism.

scholarly journals Critically coupled Fabry–Perot cavity with high signal contrast for refractive index sensing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gyeong Cheol Park ◽  
Kwangwook Park
Keyword(s):  
Refractive Index ◽  
Wavelength Range ◽  
Near Infrared ◽  
Optical Cavity ◽  
High Signal ◽  
Critical Coupling ◽  
Coupling Condition ◽  
Perfect Absorption ◽  
Fabry Perot ◽  
Signal Contrast

AbstractPerfect absorption at a resonance wavelength and extremely low absorption at the wavelength range of off-resonance in a one-port optical cavity is required for refractive index (RI) sensing with high signal contrast. Here, we propose and analyze an absorption-enhanced Fabry–Perot (MAFP) cavity based on a critical coupling condition in a near-infrared wavelength range. For a one-port cavity, a thick bottom Au is used as a mirror and an absorber. To achieve the critical coupling condition, a top dielectric metasurface is employed and tailored to balance the radiation coupling and the absorption coupling rates, and the one-port cavity is theoretically analyzed using temporal coupled-mode theory. We investigate two types of MAFP structures for gas and liquid. The gas MAFP cavity shows a sensitivity of ~ 1388 nm/RIU and a full-width at half-maximum of less than 0.7 nm. This MAFP cavity resolves the RI change of 5 × 10−4 with a reflectance signal margin of 50% and achieves a signal contrast of ~ 100%. The liquid MAFP cavity shows a sensitivity of ~ 996 nm/RIU when RI of liquid changes from 1.30 to 1.38. With tailoring the period of the metasurface maintaining its thickness, a signal contrast of ~ 100% is achieved for each specific RI range.

scholarly journals Perfect absorption of water waves by linear or nonlinear critical coupling

2019 ◽  
Vol 114 (1) ◽  
pp. 013901
Author(s):  
E. Monsalve ◽  
A. Maurel ◽  
P. Petitjeans ◽  
V. Pagneux
Keyword(s):  
Water Waves ◽  
Critical Coupling ◽  
Perfect Absorption

scholarly journals Interferometric control of magnon-induced nearly perfect absorption in cavity magnonics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J. W. Rao ◽  
P. C. Xu ◽  
Y. S. Gui ◽  
Y. P. Wang ◽  
Y. Yang ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Molecular Detection ◽  
Coupled System ◽  
Critical Coupling ◽  
Perfect Absorption ◽  
Reflection And Transmission ◽  
Single Beam ◽  
Coherent Perfect Absorption ◽  
Channel Interference ◽  
On Chip

AbstractThe perfect absorption of electromagnetic waves has promoted many applications, including photovoltaics, radar cloaking, and molecular detection. Unlike conventional methods of critical coupling that require asymmetric boundaries or coherent perfect absorption that require multiple coherent incident beams, here we demonstrate single-beam perfect absorption in an on-chip cavity magnonic device without breaking its boundary symmetry. By exploiting magnon-mediated interference between two internal channels, both reflection and transmission of our device can be suppressed to zero, resulting in magnon-induced nearly perfect absorption (MIPA). Such interference can be tuned by the strength and direction of an external magnetic field, thus showing versatile controllability. Furthermore, the same multi-channel interference responsible for MIPA also produces level attraction (LA)-like hybridization between a cavity magnon polariton mode and a cavity photon mode, demonstrating that LA-like hybridization can be surprisingly realized in a coherently coupled system.

Perfect absorption in a monolayer graphene at the near-infrared using a compound waveguide grating by robust critical coupling

2019 ◽  
Vol 17 (1) ◽  
pp. 010501
Author(s):  
Jinhua Hu Jinhua Hu ◽  
Jia Fu Jia Fu ◽  
Xiuhong Liu Xiuhong Liu ◽  
Danping Ren Danping Ren ◽  
Jijun Zhao Jijun Zhao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Monolayer Graphene ◽  
Critical Coupling ◽  
Perfect Absorption ◽  
Waveguide Grating
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