S1
Supporting Information
Bioinspired disordered flexible metasurfaces for human tear analysis using broadband
surface
-
enhanced Raman scattering
Vinayak Narasimhan,
1
Radwanul Hasan Siddique,
1,
2
Haeri Park
1
and Hyuck
Choo
3
,
4
*
1
Department of Medical Engineering, California Institute of Technology, Pasadena, CA 91125,
USA.
2
Image Sensor Lab, Samsung Semiconductor
,
Inc.,
Pasadena, CA
91101
, USA
.
3
Department of
Electrical
Engineering, Califor
nia Institute of Technology, Pasadena, CA 91125,
USA.
4
Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Gyeonggi
-
do,
16678, South Korea.
* E
-
mail:
hyuck.choo@samsung.com
;
hchoo@caltech.edu
Contents:
Figure S1.
Schematic of the different stages of the 3
-
dimensional phase separation process.
Figure S2.
Characterization of the flex
-
MS FDTD model.
Figure S3.
Extinction cross
-
section as a function of nanogap size.
Figure S4.
Comparison of
|
E
/
E
o
|
2
enhancement from a single MIM structure and a periodic
array.
Figure S5.
The simulated flex
-
MS FDTD model.
Figure S6.
Comparison of an MIM structure with an open and covered nanogap.
Figure S7.
Suppression of background signal by the flex
-
MS.
S2
Figure S1
.
(a
-
f)
Schematic of the different stages of the 3
-
dimensional phase separation
process
.
1
Figure S2
. An ensemble with (a)
diameter distribution of
98
±
30
nm and (
b
) a short
-
range
ordered periodicity of 3
19
±
3
7
nm was simulated
using FDTD
.
S3
Figure S3
. Extinction cross
-
section of a single MIM nanostructure as a function of nanogap size.
A gap size of 9 nm is optimally
tuned to match the laser wavelength.
Figure
S
4
. (a) The |
E
/
E
o
|
2
enhancement from a single MIM structure of diameter 100 nm and
gap
9
nm.
Inset shows the field profile of the single MIM structure.
(b) The field
-
profile of a
periodic distribution of MIM structures (diameter: 100 nm, gap:
9
nm, periodicity: 32
0 nm)
showing no coupling between adjacent structures.
Figure S5.
The 3
.5
x 3
.5
μm flex
-
MS ensemble simulated on FDTD. Scale bar:
6
00 nm.
S4
Figure S6
.
(a) MIM structures with an open 9 nm gap where the experimentally observed
scattering cross
-
section is in agreement with that computed through FDTD. The scattering peak
is
tuned close to the laser excitation wavelength
휆
!
of 785 nm. (b) The same structures with a
covered nanogap demonstrating a resonance in the visible regime.
Figure S7.
Effective suppression of background signal from the underlying polymer substrate by
the flex
-
MS. In comparison, the SERS spectra of
150 μM uric acid on the flex
-
MS is shown.
References
(1)
Huang, C. Phase Separation in Thin Polymer Films: From Self Stratification to Polymer
Blend Lithography. Ph.D. Thesis, T
echnische Universität, Darmstadt, 2015.