NanoTera RTD Project

IRSENSIntegrated sensing platform for gases and liquids in the near and mid-infrared rangeJ. Faist, Y. Bonetti, P. Jouy ETH Zurich

Plenary meeting Zurich April 26th, 2012 IrSens

Sensing needsgas fluidMedicine (Diagnosis, Monitoring)

Environment (Pollution, Modelling)

Sensing of small molecules (CO, CO2, NxOy, ...)

Sensitive Selective Portable, Low Power

Infrared Spectroscopy

Semiconductor System

IrSens

Approach: optical sensingLaser detector N O

IrSens

Project Synopsis: PartnersCombine expertise of 7 Swiss groups Gas

Software

Sources

Interaction system

DetectionBenchmarking

Liquid

IrSens

Pilot/focus applicationsGas: CO2 isotope ratios, e.g for plant respiration monitoring environment Liquid: Cocaine in saliva detection (presence yes/no) traffic securityPlatform: develop tools and techniques Collaboration with industryIrSens

Measurements in Gases

IrSens

Gas sensor block diagram

Source: DFB Quantum Cascade Laser

Interaction system: cylindrical mirror cell

Detection: Quantum Cascade Detector

Goal: all parts have a low production cost in large volumeCompared to standard systems: - Replace MCT detector with III-V based quantum cascade detector - Develop a new interaction cell

IrSens

First generation cell

real-time ambient air measurement

Technique 1s precision () best precision ()

DA (NanoTera) 0.47 0.05 (250s)

WM (NanoTera) 0.76 0.07 (450s)

PA (NanoTera) 58.0 0.60 (8000s)

Picarro (CRDS reference) 0.67 0.1 (300s)

Published: Manninen et al., Applied Physics B (2012)

IrSens

2nd generation cell: one piece toroidal mirrorSimulation of toroidal cell:

Advantages: - Compact - Robust - Easy to align - Large path to volume ratio

Difficulties - Surface roughness - Interference phenomena -> fringes

Solution - All reflective optics - Careful beam shaping

IrSens

Software acquisition

- Full control on experimental environment, laser operation, and data acquisition - Real-time fitting engine (up to 1kHz) - Directly linked to HITRAN database

-> real-time isotope ratio measurements

IrSens

Integrating QCL, QCD, Preamp and measurement cellDAQ and simulation (FHNW)

QCL (ETHZ)

QCD preamp (EPFL)

Optical cell (Empa)

Intersubband quantum cascade detector (QCD) (UniNE)

10 cm 19"-rack instrument (Empa)

IrSens

Isotope ratio measurements with toroidal cellQuantum cascade detector: 13C/12C ratio: 0.7 accuracy in 1 s 0.07 in 1000s628/626 Norm. Ratio

Commercial MCT detector: 13C/12C ratio: 0.3 accuracy in 1 s

636 / 626 Norm. Ratio

1.05 1 0.95 0 10-2

1.05 1 1000 2000 3000 4000 time (s) 5000 6000 7000

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High accuracy isotope measurements with toroidal cell achieved Goal of 0.1 , necessary for health and environnemental applications, is reached First successful combination of QCL with QCD: all III-V detection

IrSens

Measurements in liquidsQCL Source Waveguide

QCD Detector

Inlets and Mixer

Outlet

Technological blocks: QCL source, waveguide, QCD detector, microfluidics

Benchmarking of the measurements Extraction and spectroscopy: ATR and direct detection

Integration

IrSens

Measurements in liquidsQCL Source Waveguide

QCD Detector

Inlets and Mixer

Outlet

Technological blocks: QCL source, waveguide, QCD detector, microfluidics

Benchmarking of the measurements Extraction and spectroscopy: ATR and direct detection

IntegrationIMTInstitut de microtechnique - 14 -

Si/Ge waveguide Process key steps:I. II. Nitride coating (hard mask) Ge etching (CF4 + O2 recipe)

Losses measurement (Fringes) I. 13 mm long II. Bend structure III. Losses from 3 to 11 dB/cm

Loss measurements: Y. Chang

IrSens

InP/InGaAs waveguide Process key steps:I. Nitride coating (hard mask) II. InGaAs etching (MORIE recipe) III. Chemical polish (HBr)

Losses measurement (Fringes)

I. II. III. IV. V.

20 mm long Bend structure 1 chip and 5 WGs Average losses 6 dB/cm Better reproducibility

IrSens

InP/InGaAs waveguide Far field emission

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IrSens

Measurements in liquidsQCL Source Waveguide

QCD Detector

Inlets and Mixer

Outlet

Technological blocks: QCL source, waveguide, QCD detector, microfluidics

Benchmarking of the measurements Extraction and spectroscopy: ATR and direct detection

Integration

IrSens

Improved Droplet-Based Liquid-Liquid Extraction

Parallel Flow

Merging Drainage

Extraction

Droplet Generation

Parallel Flow

outlet inlet

Saliva PCE Cocaine

IrSens

Micro-fluidic droplet-based liquid-liquid extraction

Parallel Flow

Merging Drainage

Extraction

Droplet Generation

Parallel Flow

outlet inlet

Saliva PCE Cocaine

IrSens

Micro-fluidic droplet-based liquid-liquid extraction

Movie!

IrSens

Measurements in liquidsQCL Source Waveguide

QCD Detector

Inlets and Mixer

Outlet

Technological blocks: QCL source, waveguide, QCD detector, microfluidics

Benchmarking of the measurements Extraction and spectroscopy: ATR and direct detection

IntegrationIMTInstitut de microtechnique - 22 -

Sample preparation

Extraction of the cocaine from the saliva:

Saliva filtered (0.2 m)

+ cocaine

Extraction of the cocaine with a solvent (C2Cl4)

Reference sample with cocaine directly in solvent (C2Cl4):

+ cocaine

IrSens

Spectroscopy measurementsATR-spectroscopy principle:

Measurements with an FTIR:Reference

Saliva

Spectra almost identical Extraction is very efficient and sufficiently selective

IrSens

Detection limit

1st order polynomial fit with baseline correction

Zoom

ATR limit detection with the FTIR below 1 g/ml After a single dose: ~500mg/ml We are in business!!!

1mg/ml

IrSens

Measurements in liquidsQCL Source Waveguide

QCD Detector

Inlets and Mixer

Outlet

Technological blocks: QCL source, waveguide, QCD detector, microfluidics

Benchmarking of the measurements Extraction and spectroscopy: ATR and direct transmission

Integration

IrSens

Setup and Detection Scheme

Sample Absorption coeff. C2Cl4 2 cm-1 + 10 ng/mL COC + 0.00002cm-1

Absorption Aa (1 mm)

37% + 5 10-6

IrSens

Sensitivity

Drift and noise

Best value for 42s averaging:

For 2ng/mL cocaine:

IrSens

Reproducibility Repeated measurements of

C2Cl4 Variation due to emptying/filling of the cell

Path length changes Impurities

Expected detection limit:

600 ng/mL

IrSens

Measurements in liquidsQCL Source Waveguide

QCD Detector

Inlets and Mixer

Outlet

Technological blocks: QCL source, waveguide, QCD detector, microfluidics

Benchmarking of the measurements Extraction and spectroscopy: ATR and direct detection

Integration

IrSens

Liquid sensing with waveguideInteraction region

Fluid sample

Waveguides

Micro-fluidic

Waveguide propagation loss: 3.6dB/cm Bending loss: 2.8% losses per 90o bend with a radius of 115um.

Cheap and easy fabrication

Plasma

Glass substrate

Scotch-tape

NOA81

IrSens

Integration of microfluidics and waveguidesFirst waveguide and microfluidic chip operating in the mid-IR First proof of principle cocaine measurements

Absorption of cocaine with different concentrations in C2Cl4 solutions

IrSens

Had quite an (popular) impact!

IrSens

Conclusion Compact setup First combination of QCL with QCD 13C/12C ratio: 0.6 accuracy in 1s and 0.1 in 250s

CO2

Cocaine

Benchmark measurements: fringes

Solution - All reflective optics - Anti-reflection mask

IrSens

Real-time data acquistion and data fitting software

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Full control on experimental environment, laser operation, and data acquisition Real-time fitting engine (up to 1kHz) Directly linked to HITRAN database

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Fast data acquisition and fitting combined with small cell volume

-> real-time isotope ratio measurements

IrSens

First isotope ratio measurements with toroidal cell

Quantum cascade detector: 13C/12C ratio: 0.7 accuracy in 1 s636 / 626 Norm. Ratio 636 / 626 Norm. Ratio1.05 1 500 1000 1500 2000 time (s) 2500 3000 3500

Commercial MCT detector: 13C/12C ratio: 0.3 accuracy in 1 s1.05 1 1000 2000 3000 4000 time (s) 5000 6000 7000

0.95 0 10-2

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-> High accuracy isotope measurements with toroidal cell feasible

-> First successful combination of QCL with QCD

IrSens

IrSens

Waveguides

IrSens

Waveguide Spectroscopy in Mid-IRInteraction region

Fluid sample

Fig1. Waveguide spectroscopy in liquids: Light interacts with fluid samples in the evanescent field.

Fig2. SEM image of the cross section of a Ge waveguide on a Silicon substrate

Fig3. Low propagation loss: 3.6dB/cm

Fig4. Bending loss: Waveguides with the same length but different bend numbers are measured and the bending loss is 2.8% per 90o bend while the bend radius is 115um.- 82 -

IMTInstitut de microtechnique

Integration of microfluidics and waveguides

Fig5. Waveguide with a microfluidic chip

Fig6. Measurement setup

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Measurement of cocaine in tetrachloroethylene

Fig7. Absorption of cocaine with different concentrations in tetrachloroethylene solutions

Fig8. Response time of the measurement

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