All-dielectric Metasurfaces Enabling Imaging-based Real-time Biosensing

Nanophotonics has come to light for detecting biomolecules and pathogens in an expeditious, highly- sensitive, label-free, and multiplexed manner. This is notably essential in disease prevention, early detection, drug development, and treatment monitoring. Refractometric biosensors rely on optical resonators exhibiting a resonance, which undergoes a spectral shift when the local refractive index changes due to bioanalyte bindings. Current spectroscopic approaches to monitor these wavelength shifts are using bulky, expensive, and sophisticated instrumentations, which limit their widespread exploitation, especially in point-of-care settings. Alternatively, tracking intensity changes over a narrow spectral window can substitute for collecting spectrally resolved information over a broad bandwidth to monitor the resonance shifts. Intensity-based platforms can be as simple as on-chip light sources and imaging detectors, offering miniaturization, lower cost, and portability to nanophotonic biosensors. However, intensity-interrogation is prone to noise factors, making them unreliable. Therefore, there is a need for novel approaches for robust and accurate miniaturized nanobiosensors that can also have an easier path forward to commercialization.