Sensitive optical biosensors for unlabeled targets: a review.

DOI: 10.1002/adom.201801433 Scientific American selects plasmonic sensing as the top 10 emerging technologies of 2018.[15] Almost every single new plasmonic or photonic structure would be explored to test its sensing ability.[16–29] These works tend to report the sensing performance of their own structure. Some declare that their sensitivity breaks the world record. However, there is still a missing literature on what the world record really is, the gap between the experiments and the theoretical limit, as well as the differences between metal-based plasmonic sensors and dielectric-based photonic sensors. To push plasmonic and photonic sensors into industrial applications, an optical sensing technology map is absolutely necessary. This review aims to cover a wide range of most representative plasmonic and photonic sensors, and place them into a single map. The sensor performances of different structures will be distinctly illustrated. Future researchers could plot the sensing ability of their new sensors into this technology map and gauge their performances in this field. In this review, we focus on optical refractive index (RI) sensors with no fluorescent labeling required. We will utilize two parameters to characterize and compare the performance of optical RI sensors: sensitivity to RI change (denoted by symbol SRI) and figure of merit (in short, FoM). For simplicity, we restrict our discussions to bulk RI change, where the change in RI occurs within the whole sample. There is another case where the RI variation occurs only within a very small volume close to the sensor surface. This surface RI sensitivity is proportional to the bulk RI sensitivity, the ratio of the thickness of the layer within which the surface RI variation occurs, and the penetration depth of the optical mode.[6] The bulk RI sensitivity defines the ratio of the change in sensor output (e.g., resonance angle, intensity, or resonant wavelength) to the bulk RI variations. Here, we limit our discussions to the spectral interrogations and the bulk RI sensitivity SRI is given by[3,5–7,30]

Optical Refractive Index Sensors with Plasmonic and Photonic Structures: Promising and Inconvenient Truth

In optics, the two main mechanisms for enhancing the Goos-H\"anchen (GH) shift of a reflected light beam have a common shortcoming: The maximum shift is located exactly at the reflectance dip, which makes the reflected beam hard to detect. Here the authors tune the excitation of guided modes in a compound grating-waveguide structure, to realize quasibound states in the continuum (quasi-BICs) with ultrahigh $Q$-factors. Assisted by these quasi-BICs, the GH shift at the reflectance peak can be greatly enhanced. This giant GH shift with high reflectance can be used for $e.g.$ ultrasensitive sensors, wavelength-division (de)multiplexers, optical switches, and polarization beam splitters.

Giant Enhancement of the Goos-Hänchen Shift Assisted by Quasibound States in the Continuum

A high-sensitivity temperature sensor based on the enhanced Goos-Hanchen effect in a symmetrical metal-cladding waveguide is theoretically proposed and experimentally demonstrated. Owing to the high sensitivity of the ultrahigh-order modes, any minute variation of the refractive index and thickness in the guiding layer induced by the thermo-optic and thermal expansion effects will easily give rise to a dramatic change in the position of the reflected light. In our experiment, a series of Goos-Hanchen shifts are measured at temperatures varying from 50.0 °C to 51.2 °C with a step of 0.2 °C. The sensor exhibits a good linearity and a high resolution of approximately 5×10(-3) °C. Moreover, there is no need to employ any complicated optical equipment and servo techniques, since our transduction scheme is irrelevant to the light source fluctuation.

High-sensitivity temperature sensor using the ultrahigh order mode-enhanced Goos-Hänchen effect

We propose a compact 1-μm-radius microring resonator sensor based on a hybrid plasmonic waveguide on a silicon-on-insulator substrate. The hybrid waveguide is composed of a metal-gap-silicon structure, where the optical energy is greatly enhanced in the narrow gap. We use the finite element method to numerically analyze the device optical characteristics as a biochemical sensor. As the optical field in the hybrid micoring resonator has a large overlap with the upper-cladding sensing medium, the sensitivity is very high compared to other dielectric microring resonator sensors. The compactness of the hybrid microring resonator is resulted from the balance between bending radiation loss and metal absorption loss. The proposed hybrid microring resonator sensors have the main advantages of small footprint and high sensitivity and can be potentially integrated in an array form on a chip for highly-efficient lab-on-chip biochemical sensing applications.

https://www.mdpi.com/1424-8220/11/7/6856/pdf

Miniature microring resonator sensor based on a hybrid plasmonic waveguide.

A structure of symmetrical metal-cladding waveguide, which contains optically nonlinear material in the guiding layer, is proposed to control the lateral shift of the reflected beam via an external electric field. Owing to the high sensitivity of ultrahigh-order modes, any minute index change of the waveguide will lead to a dramatic variation of the resonance condition, which gives rise to a change of the lateral beam displacement. Experimental result shows that the electric control of the lateral beam shift is realized in a range of 720μm.

Electric control of spatial beam position based on the Goos–Hänchen effect

It is demonstrated that the superprism effect is greatly enhanced in the configuration of a symmetrical metal-cladding waveguide owing to the strong dispersion effect of ultrahigh-order modes. The experimental result shows that a notable spatial displacement of the reflected beam as large as 0.9 mm is achieved within a variation of 0.15 nm in wavelength.

Enhancement of the superprism effect based on the strong dispersion effect of ultrahigh-order modes

The invention discloses a micro-displacement measurement method in the field of precision measurement technology, which bases on Goos-Hanchen(GH) shifts enhancement effect stimulated by guide mode, high parallel degree laser is shined into metal film deposited on prism-air gap-double-coated metal waveguide structure which is made of metal films deposited on optical glass, the laser is coupled into waveguide in meeting phase-matching, which causes reflective phases to change drastically comparing incident phases, and reflected beam Goos-Hanchen (GH) shifts are enhanced greatly, shifts are very sensitive to thickness changes of guided wave air gap, using the character, through detecting reflected light Goos-Hanchen (GH) shifts change, the optical glass position change compared to the prism position is measured, thus achieving the measurement of the measuring object shifts. This invention can achieve high sensitivity, fast and accurate real-time measurement, and the method is simple, and has good anti-interference capability, and can be widely used in construction, geological monitoring, processing machinery, materials testing of micro-shifts measurement.

Micro-displacement measurement method based on guided mode excitated Goos-Hanchen shift enhancement effect

A method for detecting laser wavelength by Goos-Hanchen shift characteristic belongs to the technical field of precision measurement In the method, a laser beam having a divergence angle smaller than 04mrad is emitted on a double metal-cladding waveguide structure which consists of a metal film deposited on a prism, an air gap and a metal film deposited on optical glass When a coupling condition is satisfied, the laser enters the waveguide The reflected light generates an absorption peak, and phase of the reflected light rapidly changes relatively to the phase of incident light so that the Goos-Hanchen shift of the reflected light is greatly increased; and the wavelength of a wave output by the laser is measured by detecting the Goos-Hanchen shift of the reflected light according to the characteristic that the Goos-Hanchen shift is extremely sensitive to the wavelength change of the incident laser The supersensitive, fast and accurate real-time measurement can be achieved by the method, and the measurement method is simple, has strong anti-interference capability, and can be widely applied to the aspects such as wavelength resolution and shift suppression of laser output waves in a dense wavelength division multiplexing system and the like

Method for detecting laser wavelength by Goos-Hanchen displacement characteristic

Electrical tuning of polarization beam splitting is demonstrated in the structure of symmetrical metal-cladding waveguide by introducing optically nonlinear material into both the coupling prism and the guiding layer. Due to the anisotropy of the coupling material, different excitation conditions for TE and TM modes are obtained, which results in polarization-dependent reflections and transmissions. And the splitting effect of the two orthogonally polarized beams can be manipulated through an electrical modulation of the guiding layer properties.

Tunable polarization beam splitting based on a symmetrical metal-cladding waveguide structure.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Yi Wang

Author Tools

Chat about Author