Optical Interrogation Techniques for Nanophotonic Biochemical Sensors

Abstract

The manipulation of light via nanoengineered surfaces has excited the optical community in the past few decades. Among the many applications enabled by nanophotonic devices, sensing has stood out due to their capability of identifying miniscule refractive index changes. In particular, when free-space propagating light effectively couples into subwavelength volumes created by nanostructures, the strongly-localized near-fields can enhance light’s interaction with matter at the nanoscale. As a result, nanophotonic sensors can non-destructively detect chemical species in real-time without the need of exogenous labels. The impact of such nanophotonic devices on biochemical sensor development became evident as the ever-growing research efforts in the field started addressing many critical needs in biomedical sciences, such as low-cost analytical platforms, simple quantitative bioassays, time-resolved sensing, rapid and multiplexed detection, single-molecule analytics, among others. In this review, the optical transduction methods used to interrogate optical resonances of nanophotonic sensors will be highlighted. Specifically, the optical methodologies used thus far will be evaluated based on their capability of addressing key requirements of the future sensor technologies, including miniaturization, multiplexing, spatial and temporal resolution, cost and sensitivity.

Plasmonic Metasurfaces for Medical Diagnosis Applications: A Review

“…The light-matter interaction through the evanescent field of SPR is a common mechanism for biomedical analytes detection [ 56 ]. The metasurface sensors based on SPR and LSPR are mainly based on the analysis of angle, wavelength, phase, and other plasmon parameters [ 57 , 58 , 59 , 60 , 61 , 62 ]. Metasurfaces-based SPR refers to a kind of artificial meta-atoms (usually periodic) that are designed to manipulate the amplitude, phase, and polarization of electromagnetic waves [ 63 , 64 , 65 , 66 , 67 , 68 ].…”

Surface Plasmonic Sensors: Sensing Mechanism and Recent Applications

“…The detecting approaches used in SPR/LSPR sensors include analyzing the changes of wavelength [ 31 ], angular [ 32 ], phase [ 33 ] and polarization [ 34 ] parameters of the plasmonic structures. Note that the basic physical parameter that can be directly measured is light intensity; thus, different interrogation systems conventionally utilize optical instruments to convert changes in phase, angle, polarization into intensity variations [ 35 ]. Despite the tremendous success of plasmonic sensors, it is recognized that the sensitivity and precision of plasmonic sensors are beginning to reach a fundamental limit by quantum fluctuations of light known as shot-noise limit (SNL) regardless of whether intensity or phase is measured [ 36 , 37 ].…”

Common-path interferometric label-free protein sensing with resonant dielectric nanostructures

“…An interferometric version of the well-known surface plasmon resonance (SPR) modality was first introduced in 1997 by Kabashin and Nikitin 6 , demonstrating an improvement in LOD of two orders of magnitude (to 4 × 10 −8 RIU) compared with more traditional noninterferometric angular interrogation. The downside of this method, however, is the trade-off between sensitivity and dynamic range 7,8 . For example, interferometric SPR can achieve LODs of Δn ≈ 10 −8 , but this sensitivity is only achieved over 5 × 10 −5 RIU, unless advanced designs are used that are costly, cumbersome, and not suitable for POC applications 7 .…”