Multi-channel Surface Plasmon Resonance Silicon Waveguide Sensor System
Date Issued
2006
Date
2006
Author(s)
Lin, Hsueh-min
DOI
en-US
Abstract
Biosensors using guided wave have been very popular in the past few
years due to its high sensitivity and possible commercial opportunity. Surface
plasmon resonance (SPR) as basic transduction method for chemical sensing is
quite well-known. SPR sensors have the advantages of label-free and real-time
detection. The waveguide configuration allowed SPR detection miniaturized,
unlike traditional angle-modulated SPR detection which is limited in a standard
lab-size room. The waveguide was manufactured by semiconductor technique
which can be used for mass production.
An SPR optical sensor system based on ridged-waveguides on a precise
optical bench was designed and built in this thesis. Multi-channel design and
specialized optical bench allowed the sensor to perform multiple sensing. The
waveguide sensors fabricated by MEMS technology consisted of a 10μm SiO2
substrate layer (n= 1.469), 10μm Ge doped SiO2 channel guide (n= 1.492), both
are produced by plasmon enhanced chemical vapor deposition (PECVD) and
wet etching standard semiconductor manufacturing procedure. Optimal process
parameters had been acquired during previous studies to understand the
resultant refractive index and doping concentration and dimensional
specifications . A 50 nm gold thin film, 500μm in length was placed on top of
ridge waveguide and SPR signal detections using E-beam lithography process.
The waveguide chip was 1cm x 1cm in dimension. A surface polishing was
needed for an even distribution of light focusing into the waveguide.
Obtaining data from SPR waveguide sensor required a precise measuring
platform with various degrees of freedom. In this thesis, different platforms
were built for different applications. End-firing method was built with two
V
objective lenses on precise six-degree moving stage to obtain single channel
detection. Broadband light and spectrometer were used in this kind of detection
for observing the change of surface plasmon wavelength peak. For multiple
detection, two methods were been used. For focusing light source (633nm laser)
into the waveguide, in this method, a cylindrical lens for focusing. Broadband
light source (Tungsten light or miniaturized LED), a parallel bundle of fiber
were used, again those fiber bundles were mounted onto precise six-degree
moving stage. The light from SPR waveguide was collected by spectrometer. A
polarizer was put in between the waveguide and light detector to ensure the TM
polarized direction.
Various concentrations of glycerol and glucose were tested on two
different configurations: single channel configuration and multi-channel
configuration. Transmission loss due to SPR spectrum in comparison to the
aero environment is calculated from transmission spectrum obtained from
spectrometer. A transmission loss spectrum of nano particles deposited on gold
sensing layer was demonstrated using the multi-channel configuration.
Subjects
表面電漿共振
光波導
生物晶片
Surface plasmon resonance
Optical waveguide
Biochip
Type
thesis
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