Chapter 5
Conclusions
According to the various analysis of 2-D silicon nanopillars array
with cubic and hexagonal lattice of several shapes are compared in
Chapter 2. From the comparison of the results, hexagonal structures of
cylinder are the best arrange of sensor design. In Chapter 3, we
successfully fabricated optical high sensitivity sensor using silicon
nanopillars array by low-cost self-assembly nanosphere lithography
method to generate high aspect ratio silicon nanopillars by reactive ion
etching and photo-assisted electrochemical etching. The silicon
nanopillars array sensor average parameters are periodicity a = 250 nm,
pillar radius r = 100 nm, and pillar height was 1μm. According to the
various condition are comparing simulation results with experimental
measurement at TE mode, TM mode for 1.55 um of wavelength,
respectively. We can prove that our experimental results are well to
approach the calculations. In Chapter 4, we will test the virus, DNA and
germ which are discussed extensively. In the demonstration of the
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experimentation, small molecules (Plasmid 、 HVS-1 、 Glucose 、
Saccharomyces) can be judged by monitoring the polarize variation. We
judge the bio-molecules from the slight different changes of refractive
index, which caused sensor strongly polarization sensitivity, and observe
signal constellation by Poincaré sphere based on Polarization Shift
Keying (PolSK) fiber-optic system is as shown in Fig. 5-1 and Fig. 5-2
for TE mode and TM mode, respectively, which makes the sensors
extremely sensitive to the refractive index slight change resulting from
the infiltration of bio-molecules. From the result we can obviously
observe the trajectory of the various polarization states. They have a
unique polarization states. This is a very promising value from this
preliminary experiment in comparison with other planar optical
biosensors. We give summary of sensor in table 5-1. From table 5-1, we
can obviously see higher sensitivity of the sensor for our designed. In the
future, we will set up the database for the polarization of Si nanopillars
array based on PolSK fiber-optic system. We believe this novel sensor
using Si nanopillars array based on PolSK fiber-optic system technology
can bring revolutionary medical treatment to the mankind.
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Fig. 5-1 The average results of the state of polarization measurement at various samples for TE mode
Fig. 5-2 The average results of the state of polarization measurement at various samples for TM mode
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Table 5-1 The basic performance comparisons of several optical sensors list
Performance
Structures
Material Sensitivity Year Ref.
Surface plasmon
resonance Polymer 1×10−2 2003 [16]
ARROWs Silicon 6× 10−4 2003 [17]
Dual-Window Waveguide Silicon 2×10−1 2004 [18]
Photonic Wire SOI 1×10−2 2005 [19]
Photonic crystal
PS-PMMA 1×10−2 2005 [20]Si nanopillars array
Silicon 1×10−4 2007 O.F.S.L.120
