Transcript Porous Silicon Optical Sensors Tanya Hutter and Shlomo Ruschin

Photonic devices laboratory
Sensor-related projects
Shlomo Ruschin
•Environment and Biological Porous Silicon Optical Sensors
Sensor based on Periodically Segmented Waveguides
Sensors based on active lasing optical waveguides
Critical sensitivity effect: SOI sensor
Critical sensitivity effect : PSi sensor
Collaborators:
Prof. Jehudit Rishpon
Prof. Menachem Nathan
Dr. Asher Peled
Tanya Hutter
Keren Hakshur
Tel-Aviv
University
Porous Silicon Optical
Sensors
Tanya Hutter and Shlomo Ruschin
Motivation (1) porous silicon
sensors
Light source and
receiving fiber
PSi Sensors
Ammonia
storage
warehouse
ADVANTAGES:
• Cheap
• Small
• Remote
• Passive (can be
used in flammable
environment)
N
N
H3N
H3N
H3 NH3 H3 NH3
ALARM !
Motivation (2) porous silicon
sensors
• Breath analysis for clinical applications
Ammonia is listed
as one of the
marker molecules
that can identify
kidney impairment.
Porous silicon
• Porous silicon (PSi) is a material formed
by electrochemical etching of crystalline
silicon.
• ‘nano-sponge’
500 nm
Porous silicon (PSi) - Why !?!?
Increased surface interaction area 200-1000 m2/cm3.
Simplicity and repeatability of fabrication.
Ability to produce pores in the range of 30Å to 1μm and
porosities of 10-90%.
Compatibility with technology: easily integrable with Sibased microelectronics.
Biocompatible
H. Ouyang et al., Frontiers in Surface Nanophotonics, 2007
Optical Measurement Setup
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•
Light from tungstenhalogen lamp passes
through collimating
lens.
The reflected rays
are collected and
transmitted to a PC
via spectrometer.
Outlet
Gas chamber
White light source
Porous Silicon
Spectrometer
Humidifier
•
The reflected spectra
is collected at
wavelengths 4001000nm.
Flowmeters
NH3
Gas
Experimental optical setup
N2
Gas
Ammonia vapor & pH indicator
Yellow
The reflected spectrum
7000
Nitrogen
Ammonia
6000
Inte nsity [counts]
• After Exposure:
ammonia reacts
with BTB, and the
sample changes its
color from yellow to
blue.
5000
4000
3000
2000
absorbance at 400-430nm
1000
400
Blue
absorbance at 550-650nm
450
500
550
600
650
700
Wa ve le ngth [nm ]
750
800
850
900
Multi-Sensing Principle
Gas
out
Porous
silicon
surface
Gas
in
Reflection
1
0.5
0
500
600
700
800
Wavelength, nm
900
1000
Multi-Sensing Principle
•
Sensor array concept.
•
Each section is made of porous silicon with a different functionality.
•
White light is collimated to illuminate the entire sample.
•
The reflected light from all the sections is measured simultaneously in a
non-imaging configuration using a single detector.
•
The obtained spectrum consists of many overlapping interference spectra
each reflected from a different sensor section.
70000
70000
2Bwith biotin
60000
2Bwith silan
50000
2B with Biotin after 4 days
2B with Biotin and PBS
2B with Avidin after
30min incubation
2B with Avidin dry sample
60000
40000
50000
Intensity
Intensity
Model system: Biotin-Avidin
30000
20000
40000
30000
20000
10000
10000
0
400
600
800
1000
Wave length [nm]
PSi sample before and after biotin
connection to the PSi sensor.
0
400
500
600
700
800
Wave length [nm]
900
PSi sample before and after Avidin
connection to the PSi sensor.
1000
Periodically Segmented Waveguides and sensors
based upon them
PMZ
Pref
The basic PSW-MZI sensor
Processing is simpler
(single photolithography step)
Examples of sensing systems experimentally tested:
•
DNA Hybridization
•
Toxics- Parathion hydrolase
•
Antigen binding (Biotin-Avidin)
DNA Hybridization
Sensors based on active lasing optical
waveguides
Concept
l
Architecture & detection scheme
Suitable for both remote sensing & biomedical
device
Monolithic rare-earth doped sol-gel tapered rib waveguide laser
Nd-doped tapered rib waveguide laser- schematic view, not drawn to
scale for clarity
Emission spectra of the laser device for
different input pump powers.
Output lasing power as a function of input pump
power for different pump wavelengths
Optical gain measurement setup
Critical sensitivity effect in an interferometer sensor
Ronen Levy, Shlomo Ruschin*, and Damian Goldring
2mm
The Critical Sensitivity Effect
10
10
10
0
10
-2
10
Transmission
Transmission
10
-4
-6
10
(a)
550
600
10
650
700
750
800
850
0
-2
-4
-6
(b)
550
900
600
10
10
10
0
10
-2
10
Transmission
Transmission
10
λcp=735.3 nm
-4
-6
600
10
10
(c)
550
650
700
750
800
Wavelength, nm
650
700
750
800
850
900
Wavelength, nm
Wavelength, nm
850
900
0
-2
λcp=753.7 nm
-4
-6
(d)
550
600
650
700
750
800
Wavelength, nm
850
900
Critical sensitivity effect in an interferometer sensor
Ronen Levy, Shlomo Ruschin*, and Damian Goldring
Splitting effect
Sensor output power for the scanned wavelength range without
illumination (Blue, solid line) and with illumination (Green, dashed line).
Dynamic Range Enhancement and
Phase-Ambiguity Elimination
in Wavelength-Interrogated Interferometric Sensor
Tanya Hutter,1 Stephen R. Elliott,1 and Shlomo Ruschin2,*