Highly Sensitive and Tunable Fano-Like Rod-Type Silicon Photonic Crystal Refractive Index Sensor

Highly Sensitive and Tunable Fano-Like Rod-Type Silicon Photonic Crystal Refractive Index Sensor

A highly sensitive and tunable 2D rod-type silicon photonic crystal cavity based biosensor configuration has been designed and numerically analyzed. The structure is optimized so that the light-matter interaction is maximized in the cavity region. Out-of-plane light confinement is achieved by sandwi...

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Bibliographic Details
Published in:IEEE sensors journal 2021-03, Vol.21 (6), p.7551-7557
Main Authors: Kilic, Selahattin Cem, Kocaman, Serdar
Format: Article
Language:eng
Subjects:
Actuation
Air gaps
Biosensors
Metal plates
photonic crystal cavity
Photonic crystals
Refractive index
refractive index sensor
Refractivity
Resonance
Resonant frequency
Rods
Sensitivity
Sensors
Silicon
tunable sensor
Tuning
Waveguides
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Summary:A highly sensitive and tunable 2D rod-type silicon photonic crystal cavity based biosensor configuration has been designed and numerically analyzed. The structure is optimized so that the light-matter interaction is maximized in the cavity region. Out-of-plane light confinement is achieved by sandwiching the rods between metal plates, and tuning is achieved by introducing an air-gap between on top of the rods and the metal plate. A single rod is positioned in the middle of the waveguide so that the cavity Q-factor is enhanced by obtaining a Fano-like resonance. The air-gap between the rods and the metal plate acts as a slot structure, confining E-field in that small region and simultaneously decreasing mode-volume while making the resonance characteristics highly dependent on the gap size. This creates the opportunity to tune the resonance characteristics by electrostatic actuation via applying voltage to the top and bottom metal plates. The proposed structure has a sensitivity value of 1039 nm/RIU, a mode volume of 0.214 ( \lambda /n) 3 , flexible tuning capabilities, and is the first tunable 2D PhC rod-type refractive index sensor.
ISSN:1530-437X
1558-1748