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Single Virus Detection on Silicon Photonic Crystal Random Cavities
Keisuke Watanabe1, Hsin-Yu Wu1, Jolly Xavier1
1Department of Physics and Astronomy, Living Systems Institute, University of Exeter, Exeter, EX4 4QD, UK.
Small (Weinheim an Der Bergstrasse, Germany)
|February 26, 2022
Summary
This study demonstrates label-free detection of single viruses using silicon photonic crystal random cavities. These novel sensors achieve high sensitivity without needing pre-fabricated cavities or couplers, paving the way for advanced nanoparticle detection.
Area of Science:
- Photonics
- Nanotechnology
- Biophysics
Background:
- On-chip silicon microcavity sensors offer compactness and enhanced light-matter interaction for biomolecule detection.
- High-quality factor silicon cavities and optical coupler integration are fabrication challenges for single virus detection.
Purpose of the Study:
- To propose and demonstrate label-free single virus detection using silicon photonic crystal random cavities.
- To overcome fabrication hurdles by utilizing residual disorder for Anderson localization.
Main Methods:
- Fabrication of free-standing silicon photonic crystal waveguides without pre-defined defect cavities.
- Excitation of Anderson-localized cavity modes using a free-space beam.
- Monitoring resonance wavelength shifts upon single adenovirus binding.
Main Results:
- Achieved a quality factor (Q) of approximately 10^5.
- Observed discrete, step-like changes in resonance wavelength corresponding to single adenovirus binding (approx. 50 nm radius).
- Demonstrated label-free detection capability at the single nanoparticle level.
Conclusions:
- Silicon photonic crystal random cavities with Anderson-localized modes offer a viable platform for label-free single virus and nanoparticle detection.
- CMOS-compatible sensor chips utilizing these modes present a pathway for future ultrasensitive biosensing applications.
- Elimination of the need for pre-fabricated cavities and optical couplers simplifies sensor design and fabrication.
