Ultracompact On-Chip Multiplexed Sensor Array Based on Dense Integration of Flexible 1-D Photonic Crystal Nanobeam Cavity With Large Free Spectral Range and High Q-Factor

A method for the dense integration of one-dimensional (1-D) photonic crystal nanobeam cavity (PCNC) based integrated sensor array (1-D-PCNC-ISA) is proposed. The 1-D-PCNC-ISA consists of multiple parallel-connected sensing channels with airgap separations. On each channel, only a single flexible 1-D...

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Bibliographic Details
Main Authors: Daquan Yang, Bo Wang, Xin Chen, Chuan Wang, Yuefeng Ji
Format: Article
Language:English
Published: IEEE 2017-01-01
Series:IEEE Photonics Journal
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Online Access:https://ieeexplore.ieee.org/document/7938311/
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Summary:A method for the dense integration of one-dimensional (1-D) photonic crystal nanobeam cavity (PCNC) based integrated sensor array (1-D-PCNC-ISA) is proposed. The 1-D-PCNC-ISA consists of multiple parallel-connected sensing channels with airgap separations. On each channel, only a single flexible 1-D-PCNC sensor with large free spectral range (FSR) and high <inline-formula><tex-math notation="LaTeX">$Q$</tex-math></inline-formula>-factor is contained. With proper engineering of the FSR, multiple ultracompact high-sensitivity 1-D-PCNC sensors can be integrated into microarrays without resonance overlap, and be interrogated simultaneously between a single input/output ports. Using 3-D finite-difference-time-domain (3-D-FDTD) method, the performance of the device is investigated theoretically in the whole paper. With optimization design, a large FSR as wide as 197&#x00A0;nm and high <inline-formula> <tex-math notation="LaTeX">$Q$</tex-math></inline-formula>-factor <inline-formula><tex-math notation="LaTeX">$\sim2 \times 10^5$</tex-math></inline-formula> can be achieved. Moreover, the refractive index sensitivities of a 5-channel 1-D-PCNC-ISA as high as 170.6, 152.7, 138.5, 128.1, and 120.5&#x00A0;nm/RIU are obtained. Particularly, the footprint of a 5-channel 1-D-PCNC-ISA is <inline-formula><tex-math notation="LaTeX">$\sim7\,\mu{\rm m} \times 65\,\mu$</tex-math> </inline-formula>m (width by length), which is decreased by three orders of magnitude compared to the sensor arrays based on 2-D-PC cavity platforms. To the best of our knowledge, this is for the first time that a 1-D-PCNC based multichannel parallel-connected sensor array has been displayed with channel spacing as small as <inline-formula> <tex-math notation="LaTeX">$0.195\,\mu$</tex-math></inline-formula>m, extinction ratio <inline-formula> <tex-math notation="LaTeX">$&#x003E;20$</tex-math></inline-formula>&#x00A0;dB and <inline-formula><tex-math notation="LaTeX"> $Q$</tex-math></inline-formula>-factor <inline-formula><tex-math notation="LaTeX">$&#x003E;10^5$</tex-math></inline-formula> , respectively, without using particular materials or complexities in fabrication. Both the specific result and the general idea are promising in future ultracompact lab-on-a-chip applications and nanophotonic integrations.
ISSN:1943-0655