Refractive Index Sensor Based on Metal-Clad Planar Polymer Waveguide Operating at 850 nm

Abstract

A metal-clad planar polymer waveguide refractive index sensor based on epoxy (EPO) polymer materials by using light intensity interrogation at 850 nm is designed. The polymethyl methacrylate (PMMA) material is deployed as the low refractive index (RI) buffer layer in order to better couple the optical guided mode and the surface plasmon polaritons (SPP) mode for working in water environment. The effects of the gold film thickness, PMMA buffer layer thickness, waveguide layer thickness, waveguide width, and gold length on the sensor sensing characteristics have been comprehensively studied. Simulation results demonstrate that the normalized transmission increases quasi-linearly with the increment of RI of the analyte from 1.33 to 1.46. The sensitivity is 491.5 dB/RIU, corresponding to a high RI resolution of 2.6×10−9 RIU. The designed SPP-based optical waveguide sensor is low-cost, wide-range, and high-precision, and has a broad application prospect in biochemical sensing with merits of miniaturization, flexibility, and multiplexing.

Polymer-Based Guided-Mode Resonance Sensors: From Optical Theories to Sensing Applications

“…In the different studies, Ji et al 88 reported that the sensitivity of the fabricated surface plasmon polariton (SPP) sensor reached 491.5 dB/RIU (ranging from 1.33 to 1.46) with a high refractive index resolution at 2.6 × 10 −9 RIU operated at λ = 850 nm. The sensor was fabricated over a silicon substrate and consisted of EpoClad (n = 1.57), EpoCore (n = 1.58), a PMMA film (n = 1.50) buffer, and a layer of gold.…”

Parametric study on the bimetallic cladding silica waveguide surface plasmon resonance sensor

“…In based metal-clad planar waveguide, SPP mode exists at the interface between metal and its adjacent dielectric. By studying the properties of fundamental TM mode in waveguide, it is feasible to characterize the physical mechanism of coupling between waveguide mode and SPP mode [19][20][21], as has been described in detail in our previous works [15,16]. Different from the coupled mode theory, based on the mode expansion and propagation method, the optical transmission loss is calculated according to the imaginary part of the effective RI(Im(N eff )) of the waveguide fundamental mode, and whether the phase matching condition is satisfied is estimated according to the real part of that [22].…”

“…In the implementation of the experiment, the fundamental TM mode could be excited in the input waveguide by the end-fire coupling method. The power emerging from the sensing waveguide Pout is expressed as [16]…”

“…The waveguide coupled SPPs utilizes planar optical waveguide as the coupling channel to integrate the SPR sensing area with other semiconductor optoelectronic devices to form a microchip system, which combines the dual advantages of silicon manufacturing technology and optical waveguide information transmission. In our previous work, polymer waveguide coupled SPPs sensors are studied [15,16]. Polymer waveguide is easy to fabricate and affordable.…”

Design Optimisation of Optical Planar Waveguide Sensor for Microplastics Detection in Water

“…Since the detection of the microplastics in water is intricate due to the aforementioned properties, a compact europium-aluminium (Eu-Al) doped polymer optical planar waveguide sensor, fabricated by using a micro-dispenser machine may be necessary to ascertain the presence of transparent and translucent microplastics in water. This is based on the fact that an optical polymer planar waveguide has superior properties [3][4][5][6], which include strong evanescent elds [7][8][9], highly exible, small and compact, and cost-effective manufacturing for large scale production especially through the Mosquito method [10][11][12][13]. Aside from that, the europium-aluminium doped polymer exhibits sharp red emission at 617 nm with high brightness and intensity [2,14,15].…”