Click to edit Master text styles
IRSENS II A Multi-Gas Sensor for Air Pollutants and Greenhouse Gases S.Nida1, M.J.Süess1, J.M.Wolf1, M.Beck1, J.Faist1 L. Emmenegger2, B. Tuzcon2, R. Brönnimann2, H. Looser3, T. Südmeyer4 ETH Zurich1 EMPA Dübendorf2 Fachhochschule Nordwestschweiz3 Université Neuchâtel4
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Click to edit Master text styles Motivation
Gases Medical diagnosis
Environment
Sensing of small molecules (CO, CO2, NxOy, ...) Air quality control
Selective Sensitive
Portable Low power
Infrared Spectroscopy
Semiconductor System
Process control
Leak detection
Traffic security IrSens 2 – Selam Nida
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Click Goal to edit Master text styles
Current air pollution monitor (NABEL Station) in EMPA, Dubendorf
State of the Art method • Bulky • Expensive • High power consumption
Detect the 10 most important atmospheric gases with Infrared Laser Spectroscopy IrSens 2 – Selam Nida
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Click to edit Methods of Laser Master Spectroscopy text styles Covalently bonded molecules => mechanical oscillators Rotational Vibrational modes of molecules
Ro-vibrational energy level diagram
Allowed transitions at various resonant frequencies
Absorption at this resonant frequencies • Unique fingerprint
sensitive to mass (ω=√k/m)=> distinguish Isotopes IrSens 2 – Selam Nida
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Click toAbsorption Optical edit Master Spectroscopy text styles – MIR Region MIR Energy Not enough energy to excite vibration of Molecular bonds
Fundamental mode
Overtones
Ionization
Fundamental absorption fingerprint of 10 most important pollutants IrSens 2 – Selam Nida
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Optical Click toSpectroscopy edit Master text styles
L = 36 m, p = 100 hPa 1 ppm NO2 1.3% H2O
Transmission (%) Transmission (%)
100 100 9595 9090 8585 8080
Laser tuning
1598 1598
1599 1599
1600 1600
1601 1601
1602 1602
-1
Wavenumber (cm ) -1) Wavenumber (cm
1. Tuning of the laser emission across the fingerprint region 2. Measure how much light is absorbed by the sample
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Click to Spectroscopy Optical edit Master text – Quantum styles Cascade Laser Barrier
well
Barrier
Inter-subband Lasers Multiple quantum wells
Quantum Cascade Laser Delta like joint density of states
Broad Gain: transitions possible over a broad spectral range
Selectivity
Tunability IrSens 2 – Selam Nida
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Click to editCell Interaction Master text styles Requirement: •Large optical path length- to increase the absorption signal •Minimize fringes –reduce the noise Parabolic multi-pass reflection cell •Confocal/parabolic =>12m/300ml •Robust absorption mask –highly reduced interference fringes –reduce the noise
Parabolic Multi-pass reflection cell M.Mangold, B.Tuzcon et al, Switzerland Patent 01884/12, 2012. IrSens 2 – Selam Nida
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Click to edit Master Achievements so fartext styles CO2 Spectroscopy 17O12C16O 18O12C16O 13C16O
12C16O
2
2
CO2 isotope analyzer Helicobacter pyroli Infection marker Quantify soil exchange Tracer for stratospheric air
Jouy et al, Analyst 2015 IrSens 2 – Selam Nida
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Click to edit Master Achievements so fartext styles Cocaine Spectroscopy
Jouy et al, Analyst 2015
Measurement of Cocaine in PCE
NO2 Spectroscopy the SPIE award for miniaturized Platforms at the Photonics Europe Innovation Village Dr. Markus Mangold Postdoctoral fellow c/o Dr. Lukas Emmenegger Laboratory for Air Pollution EMPA DĂźbendorf
A 36x40 cm spectroscopic platform IrSens 2 – Selam Nida
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Click to Goal Current edit Master -Multiple textGas styles sensing Simultaneous detection of the 10 most important gases
Detector
Laser Requirement: Distinct emission wavelength (Laser) for each gas Challenge: Power loss and beam combining complexity added
However, most of the components can be shared
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Click to Goal Current edit Master -Multiple textGas styles sensing Simultaneous detection of the 10 most important gases
Detector
Laser Solution: One laser emitting at multiple wavelengths
Sharing the rest of the components
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Click to edit Master text styles Multi-Wavelength Operation Cladding
in QCLs
Fabry Perot Cavity
5.38 10
5.32
Wavelength(m) 5.26 5.21
5.15 10
Intensity (AU)
1.5mmx7um
Active region (AR)
8
8
6
6
4
4
2
2
0 1860
0 1880
1900
1920
1940
Wavenumber (cm-1) EV2021-3FPDFBL
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Click to edit Master text styles Multi-Wavelength Operation
in QCLs
Wavelength Selection- Distributed Feedback Lasers (DFBs) Cladding
DFB
AR
Active region (AR)
Periodic Modulation of the waveguide effective index
λ=2*Λg*neff H. Kogelnik and C. V. Shank, Journal of Applied Physics 43 (1972). A. Yariv and P. Yeh, Optical Waves in Crystals (John Wiley and Sons, 1984).
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Click to edit Master text styles Multi-wavelength operation
of QCLs
Distributed feedbacks (DFB)
T<175K
First demonstration of multi-wavelength QCLs •Two stack active region •Two DFBs Intersubband=>delta like joint density of states Straub et. al, Electronics Letters, 2002
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Click to edit Master text styles Multi-wavelength DFB
QCLs
Single mode and multi wavelength operation 1610 0.6
1615
1905
1910
1915 0.6
DFB 1 Intensity (AU)
NO2 InP cladding Active region InP:Fe insulator
NO
0.4
0.2
0.4
0.2
electrical separation 0.0 1610
1615
1905
1910
0.0 1915
wavenumber (cm-1)
Emission at two wavelengths, one at a time with electronic switch.
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Click to edit Master text demonstration styles Twin-DFB QCLs Multiple gas (NO/NO2) detection from Automotive emission
Emissions in ambient air measured by a dual-QCL, comparison with chemo luminescence data (CLD). J. Jagerska et al. APL 105, 161109 (2014). J. Jagerska et al., Optics Express 23, 1512 (2014). IrSens 2 â&#x20AC;&#x201C; Selam Nida
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Click to edit Master Packing moretext styles Triple Wavelength Operation Triple stack active region Triple section DFB
DFB 1 electrical separation
electrical separation
Problem: Reduced power from the back section Solution: Sampled Grating DFBs Proof of concept demonstrated (J Wolf, A Bismuto Unpublished)
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Click to edit Master text styles Plans conc. range [ppb]
waven umber
2-20
1046.4
1700
1275.5
SO2
0.1-10
1352
NO2
1-100
1600
NO CO ,N2O ,H2O
1-100
1900
1-10
2179
380
2281
Trace gas NH3,O3 CH4 ,N2O ,H2O
CO2
Triple Color QCL DFB 1
Twin color DFB
Detecting 10 gases with 3 lasers IrSens 2 â&#x20AC;&#x201C; Selam Nida
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Click to edit Master text styles
T. Südmeyer
S. Nida M. Suess P. Jouy J. Faist
L. Emmenegger B. Tuzcon M Mangold J Jagerska R. Brönnimann
Thank you IrSens 2 – Selam Nida
H. Looser
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