Plasmonic crystal cavity on single-mode optical fiber end facet for label-free biosensing

Abstract

All surface plasmon resonance (SPR) devices on single-mode optical fibers' (SMF) end facets, as reported up to date, are limited by severely broad and shallow resonance spectra. The consequent poor performance when they are used as refractive index sensors, together with the challenge of nanofabrication on fiber end facets, has prohibited the development of such devices for label-free biosensing. Meanwhile, the planewave coupled, multimode fiber and fiber sidewall 2 SPR counterparts are extensively employed for label-free biosensing. In this paper, we report the design, fabrication and characterization of a plasmonic crystal cavity on a SMF end facet, which shows high performance label-free sensing capability that comes from a steep cavity resonance near the plasmonic bandedge. The experimental figure-of-merit is 68 RIU -1 , which is over twenty times improvement to previous reports. The refractive index detection limit is 3.5×10 -6 RIU at 1 s integration time. We also describe a novel glue-and-strip process to transfer gold nano structures onto fiber end facets.

Lab-on-Fiber Nanoprobe with Dual High-Q Rayleigh Anomaly-Surface Plasmon Polariton Resonances for Multiparameter Sensing

“…The band gaps of the DBRs are designed to confine the two RA-SPP resonance modes in the C + L band. Small gaps are placed between the DBRs and the plasmonic crystals to enable constructive interference between the reflections from the DBR gratings and cavity edge 28 . 2D FDTD simulations are carried out to guide the design of a 1D on-fiber plasmonic crystal cavity illuminated with a fiber-guided mode (Fig.…”

“…SPR sensors based on single-mode optical fibers face more challenges. Recently, high-Q SPR sensors were demonstrated on single-mode optical fibers by using a plasmonic crystal cavity 28,29 and a distributed-feedback surface plasmon resonator 30 for biochemical sensing and ultrasound sensing.…”

Thermal deformation of gold nanostructures and its influence on surface plasmon resonance sensing

“…Details on the operation principle of the on-ber plasmonic crystal cavity and its application for SPR sensing were reported previously. 33,35,36 The periodicities of the fabricated Au nanopatch array are 1030 nm for the cavity, 525 nm for the DBR, and 900 nm for the separation between the cavity and DBR, respectively, and the gap size is 70 nm for all the regions [ Fig. 6b and d].…”

Photothermal Effect in Plasmonic Nanotip for LSPR Sensing

“…In recent times, LSPR has been instrumental for numerous sensing applications relating to photochemistry [14], electrochemistry [15,16], material discernment and identification [2,17,18], concentration sensing [19,20], acidity sensing [21], trace element detection [22], and intercellular processes [23][24][25]. Broadly, these applications use two methods to obtain the LSPR.…”