Chemistry Reference
In-Depth Information
controversy still remains whether the concentration of glucose in tear
fl
fluid and
blood is correlated [
27
]. Tear
fluid composition is subject to change based on the
method of sample collection. Erroneous sample collection methods have caused
disagreement about the concentrations of analytes in tear
fl
fl
fluid [
22
].
5.3 Computational Modelling of Holographic Glucose
Sensors
Computation of the interaction between a Bragg grating and an electromagnetic
finite-difference time domain algorithms as the numerical analysis
provided a theoretical model of the optical properties for the holographic sensor.
The simulated geometry consisted of a computed photonic structure, which had
superpositioned laser beam interference inside a theoretical Ag
0
NP impregnated
pAAm matrix, created by three beams: (1) incident beam (reference), (2) beam
re
field using
ected internally at the pAAm
matrix-water interface. Assuming that the photonic structure only consisted of a
multilayer diffraction grating with a lattice spacing of
fl
ected from the mirror (object) and (3) beam re
fl
ʛ
/2, the optical properties
were de
ned based on angular-resolved measurements and effective index of
refraction of the pAAm matrix. Figure
5.3
shows the computed spectral response as
a laser beam (532 nm) based on the wave equation was propagated onto the
Fig. 5.3 Simulated optical response of patterned Ag
0
NP impregnated pAAm matrix. A coherent
source 1 of an incident wave (
ʻ
= 532 nm) originating from air is propagated onto the sensor. The
photonic structure reflects 3, refracts 4 and diffracts 2, which allows offsetting the diffraction for
reporting on the concentrations of analytes. The colours represent the phase of the electromagnetic
eld.
Scale bar:2
μ
m. Reprintedwith permission from [
29
] Copyright 2014 The American Chemical Society
