Review Label-free detection with high-Q microcavities: a review of biosensing mechanisms for integrated devices

Abstract

Optical microcavities that confine light in high-Q resonance promise all of the capabilities required for a successful next-generation microsystem biodetection technology. Label-free detection down to single molecules as well as operation in aqueous environments can be integrated cost-effectively on microchips, together with other photonic components, as well as electronic ones. We provide a comprehensive review of the sensing mechanisms utilized in this emerging field, their physics, engineering and material science aspects, and their application to nanoparticle analysis and biomolecular detection. We survey the most recent developments such as the use of mode splitting for self-referenced measurements, plasmonic nanoantennas for signal enhancements, the use of optical force for nanoparticle manipulation as well as the design of active devices for ultra-sensitive detection. Furthermore, we provide an outlook on the exciting capabilities of functionalized high-Q microcavities in the life sciences.

Refractometry with Ultralow Detection Limit Using Anisotropic Whispering-Gallery-Mode Resonators

“…6, which shows a 10-fold improvement in detectivity for Fourier frequencies below 0.06 Hz. Equation (5) shows that this noise immunity is achieved while the intrinsic refraction-index sensitivity is maintained at the conventional single-mode sensing level. The calculation shows that even with the large resonator used in this experiment, we obtain a detection limit of ∼8 × 10…”

“…Whispering-gallery-mode resonators (WGMR) are frequently used for refractometry and reactive biosensing due to their superb intrinsic sensitivity [1][2][3][4][5][6]. Although many different sensing schemes have been developed for different scenarios, the basic principle is always the same: the sensing target, whether gas, fluid, biomolecules, or nanoparticles, interacts with the evanescent electromagnetic field near the surface of the resonator.…”

Densely Packed Microgoblet Laser Pairs for Cross‐Referenced Biomolecular Detection

“…In the recent past research interest in photonic whispering gallery mode (WGM) structures for label‐free molecular detection has strongly increased 1, 2. Manifold geometries have been demonstrated as compact and highly sensitive devices, e.g., microtoroids,3, 4 microspheres,5, 6 microrings,7, 8 capillaries,9, 10 and optical fibers 11, 12.…”

Refractometric sensing of Li salt with visible-light Si3N4 microdisk resonators

“…[1][2][3] Sensors based on whispering-gallery mode resonators have been used for the label-free detection of single viruses, 4,5 nanoparticles, 6-9 single proteins 10 , nucleotides, 11,12 and are even used commercially. 13 Many geometries have been used for bulk refractometric sensing.…”