Year: 2022
Type: article
Abstract: On‐chip silicon microcavity sensors are advantageous for the detection of virus and biomolecules due to their compactness and the enhanced light–matter interaction with the analyte. While their theoretical sensitivity is at the single‐molecule level, the fabrication of high quality ( Q ) factor silicon cavities and their integration with optical couplers remain as major hurdles in applications such as single virus detection. Here, label‐free single virus detection using silicon photonic crystal random cavities is proposed and demonstrated. The sensor chips consist of free‐standing silicon photonic crystal waveguides and do not require pre‐fabricated defect cavities or optical couplers. Residual fabrication disorder results in Anderson‐localized cavity modes which are excited by a free space beam. The Q ≈10 5 is sufficient for observing discrete step‐changes in resonance wavelength for the binding of single adenoviruses (≈50 nm radius). The authors’ findings point to future applications of CMOS‐compatible silicon sensor chips supporting Anderson‐localized modes that have detection capabilities at the level of single nanoparticles and molecules.
Source: Small
Institutions: University of Exeter, University of Plymouth
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4214718913