Implementation and phase detection of dielectric-grating-coupled surface plasmon resonance sensor for backside incident light

Sarkar

ACS Appl. Mater. Interfaces

2020

Surface plasmon resonance-based sensors have emerged as commercially fostering portable biodetectors. The scientific community is engaged in extensive research to improve their performance in terms of sensitivity, selectivity, and reproducibility for the recognition of specific biomolecules. Essentially, there is a need for miniaturizing the size of existing sensors with innovative designs without compromising their bioaffinity and sensitivity performance. In this work, we propose and demonstrate a gratingcoupled surface plasmon polariton (SPP) sensor on a thin flat gold layer using a hybrid configuration. The proof of concept of the grating architecture has been realized through an innovative fabrication procedure, with experimental verification of its bulk sensitivity. The geometry is identical to the prismcoupling configuration, yet with miniaturization and compactness. Characteristics of the excited modes in the spectral regime of interest are investigated using the finite-difference time-domain simulations. The effective index calculation of the resonance conditions and the accompanying field distribution can identify the excited SPP and metal-assisted guided-mode resonance modes. Detailed probing of the electric field distribution of the desired SPP mode reveals an extended evanescent decay length of 1284 nm, close to the theoretical limit, and an extended propagation length of 270 μm. The experimental demonstration of the reflectance dip with two different analyte media perceived an increased bulk sensitivity of 1133 nm/RIU. Remarkably, this resonant mode exhibits sensing capabilities for a wide range of analyte refractive indexes. We believe that the fabricated configuration with observed high sensitivity and calculated ultradeep evanescent field penetration depth along with extended propagation length can lead to the designing of a hands-on biochip for detecting large biomolecules.

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Grating-Coupled Surface Plasmon-Polariton Sensing at a Flat Metal–Analyte Interface in a Hybrid-Configuration

Sarkar

ACS Appl. Mater. Interfaces

2020

“…Many of these fabrication methods of gratings consist of several steps, which leads to a longer time required to structure fabrication. There have been presented interesting results of grating-coupled SPR sensors employing grating structures, mainly one-dimensional (1D) [ 26 , 27 , 28 , 29 , 30 , 31 ]. There is an effort to achieve grating-based sensors with high sensitivity and easy and cheap fabrication.…”

Section: Introductionmentioning

confidence: 99%

“…The grating-coupled SPR sensors were used as temperature sensors [ 21 ], RI sensors [ 24 , 25 , 33 , 35 ] and as biosensors [ 10 , 18 , 19 , 32 , 36 , 37 , 38 , 39 , 40 ]. Gold-coated polymer gratings brought an efficient way for fabrication of SPR gratings instead of using thick metal layers [ 29 , 30 , 35 , 41 , 42 , 43 ]. Although many of the presented SPR structures are large-scale, the reduction in their dimensions is needed for microfluidic and lab-on-a-chip (LOC) devices.…”

Section: Introductionmentioning

confidence: 99%

IP-Dip-Based SPR Structure for Refractive Index Sensing of Liquid Analytes

et al. 2021

In this paper, we present a two-dimensional surface plasmon resonance structure for refractive index sensing of liquid analytes. The polymer structure was designed with a period of 500 nm and prepared in a novel IP-Dip polymer by direct laser writing lithography based on a mechanism of two-photon absorption. The sample with a set of prepared IP-Dip structures was coated by 40 nm thin gold layer. The sample was encapsulated into a prototyped chip with inlet and outlet. The sensing properties were investigated by angular measurement using the prepared solutions of isopropyl alcohol in deionized water of different concentrations. Sensitivity of 478–617 nm per refractive index unit was achieved in angular arrangement at external angle of incidence of 20°.

Guided Mode Induced Surface Phase Mutation for Enhanced SPR Biosensor with Dual‐Parameters Interrogation

Liu,

Guo,

Tan

et al. 2023

Adv Materials Inter

Ongoing research on the sensitivity and integration of refractive index‐based biosensors has resulted in significant advancements. Here, the study presents an enhanced surface plasmon resonance biosensor that integrates imaging technology and features dual‐parameter interrogation (intensity and phase) with guided mode coupling. By depositing a silica‐waveguide‐layer on a metal‐layer, two‐mode coupling is established to generate a high Q resonance and induce a phase mutation. The sensing performance experiment demonstrated a phase sensing sensitivity of 1.1 × 105 degree RIU−1, Q‐value of the resonant peak up to 314, and figure of merit of 300 RIU−1, superior to most standard plasmonic sensors. An in‐line phase‐polarization modulation scheme combined with imaging technology is proposed to extract the resonant phase carrying refractive index information. Additionally, a pair‐prism module is designed to optimize the sensing system configuration. Meanwhile, dual‐parameters interrogation including the intensity and phase are demonstrated, which offers potential for complementary and multi‐sensing fusion applications. The intensity interrogation also shows a considerable sensitivity of 7.2 × 104 a.u. RIU−1. Furthermore, it is combined with microfluidic chip to detect of alpha‐synuclein protein closely related to Parkinson's disease, and the limit of detection can reach 300 pg mL−1 level, which indicated a considerable potential for high‐throughput diagnosis application.