Remote Raman & Fluorescence Capabilities for Chemical

Detectionat University of Hawaii

Anupam MisraShiv Sharma

HIGP, SOEST, Univ. of Hawaii

• 5” system (532 nm) (fiber optic coupled) • 5” system (532 nm) (direct coupled)

• 8” system (532 nm) • 8” UV system (248 nm)• 16” UV system (248 nm)• 8” Raman+LIBS system • 8” Raman (785 nm)• 2” system (532 nm)• 3.5” system (tunable UV) • 2.5” Raman+LIBS+LINF+LIDAR (532 nm)• 12” UV system (248 nm, 266 nm)

* Daytime Operation* Long Detection Range (no sample collection)* Fast Response* Portable

What is Raman spectroscopy? Why need Raman spectra?

Raman spectra

Vibrational modes of molecules

Depends on atomic mass, bond lengths, bond strength, configuration, etc…

Unique spectrumfor each molecule

* Raman Fingerprints: Chemical detection with very high confidence level

ω = µk

Prof. Sir C. V. Raman Nobel Prize 1930

Laser

CCD

Notch Filter

Sample

Beam splitter

Spectrograph

0

500000

1000000

1500000

2000000

2500000

3000000

0 500 1000 1500 2000 2500 3000 3500 4000

Benzene

Ethyl benzene

NitrobenzeneN

O

O

Raman Shift (cm-1)

Inte

nsity

(cou

nts)

992

606

1178

1584

3062

3079

853 10

0311

09 1588

1347

623 770 10

02

1204

1603 29

33

3053

1445

• Raman spectroscopy can distinguish between very similar chemicals

Always the same unique spectrum for a chemical !!!

Example of Raman Spectra:

ω = µk

c = f λ

0

20000

40000

60000

80000

100000

120000

500 1000 1500 2000 2500 3000 3500 4000 4500

Raman Shift (cm-1)

Inte

nsity

(Cou

nts)

Single pulse Raman detection of Conc. Sulfuric Acid from 10 m

* 5 as-measured spectra shown

H2SO4, single pulse excitation, 10 m

55 mJ/pulse, gate width 100 ns, slit 50 µm

417

560

913

1047

1148

1370

3038

* Good technique for detecting chemicals you don’t want to handle.* No sample preparation(Chemical waste sites, airport)

Single Pulse Raman from 120 m

System Front view System to sample view

Integrated Remote Raman+LIBS System

Key Components: (a) Dual Pulse Laser, 532 nm, 15 Hz, 100 mJ/pulse(b) One gated intensified detector (ICCD) (c) One high resolution, high throughput spectrograph(d) 8-inch Telescope

Detection time = 100 ns

Single shot Raman detection of Potassium chlorate & Potassium perchlorate at 120 m

* Good reproducibility (showing 5 spectra as measured)

* Good quality (High S/N)

100 mJ, 532 nm, 50 µm slit, laser spot size 1 cm (diameter).Raman Shift (cm-1)

0

5

10

15

20

25

200 400 600 800 1000 1200 1400 1600 1800

KClO4

463

629 92

494

2

1125

1087

KClO3

Target at 120 mSingle shot excitation

Inte

nsity

(Cou

nts x

104 ) 48

7

619

939

978

Single shot Raman detection of Ammonium Nitrate& Potassium Nitrate

at 120 m distance through sealed glass bottles

* Good reproducibility (showing 5 measurements- as measured)

0

5

10

15

20

25

30

200 400 600 800 1000 1200 1400 1600 1800

NH4NO3

KNO3

1020 1040 1060 1080

NH4NO3 KNO3

Raman Shift (cm-1)

Target at 120 mSingle shot excitation

Inte

nsity

(Cou

nts x

104 )

71517

1

1043

1287

1418

1043

715

1050

1345

1360

1050

Detection time = 0.5 µs

Single shot detection of 8% TNT on silica (NESTT sample) at 120 m distance

* Good reproducibility (showing 5 measurements- as measured)

5

10

15

20

600 800 1000 1200 1400 1600 1800 2000 Raman Shift (cm-1)

8% TNT on silica at 120 mSingle shot excitation

Inte

nsity

(Cou

nts x

103 )

823

1211

1366

1535 16

19

940

1556

(O2)

Detection time = 0.5 µs

Single shot Raman detection of Urea and Sugarat 120 m distance through sealed glass bottles

* Good reproducibility (showing 5 measurements- as measured)

0

2

4

6

8

10

200 400 600 800 1000 1200 1400 1600 1800

Sugar

Urea

Raman Shift (cm-1)

Target at 120 mSingle shot excitation

Inte

nsity

(Cou

nts x

104 )

175 54

8

1011

1178 16

501541

1464

1462

1349

1239

1038

116211

26

540 85

092

2

641

402

100 mJ, 532 nm, 50 µm slit, laser spot size 1 cm (diameter).

0

100000

200000

300000

400000

0 200 400 600 800 1000 1200 1400

1136

1008

414

494

620

671

1 s (= 15 pulses)

1 pulse

Gypsum at 120 m

Raman Shift (cm-1)

Inte

nsity

(Cou

nts)

Significant improvement in Raman signal (1 s)

* Good reproducibility (5 measurements shown)

Raman Detection of Mixed grains of chemicalsat 120 m distance

* 1 s detection time* Good reproducibility (5 measurements shown)

100 mJ/pulse, 15 Hz, 532 nm, 50 micron slit, laser spot size 1 cm.

2

4

6

8

10

200 400 600 800 1000 1200 1400 1600 1800 2000

S = SulfurNap = Naphthalene AN = Ammonium Nitrate

Raman Shift (cm-1)

Target at 120 m

513

Nap

763

Nap

1021

Nap

1382

Nap

1465

Nap

1578

Nap

153

S

219

S

473

S

440

S

248

S18

5 S

715

AN

1044

AN

Inte

nsity

(Cou

nts x

104 )

Target (Gypsum CaSO4.2H2O) at 50 m

0

200000

400000

600000

800000

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Target + atmosphere

Atmosphere

Target

Raman Shift (cm-1)

Inte

nsity

(cou

nts)

1556

O2

3652

H2O

2331

N2

*11

3610

07

414

493

619

671

3405 34

96

• Detection of atmosphere, target mineral and both (as measured spectra)

0

5

10

15

20

25

200 400 600 800 1000 1200 1400 1600 1800

153 21

9

473

438

Sulfur

177 30

0

726 10

98

1442

1760

Dolomite

Anhydrite

Anatase

Quartz

417

499

609

628

676

1017

1129

1160

206

264

694

355

394

464

800

1160

143

396

515 63

8

Raman Shift (cm-1)

Minerals at 9 m, 1 s (3 measurements shown for each mineral)

Inte

nsity

(Cou

nts x

106 )

30

2” compact Raman+LIBS system

532 nm, 30 mJ/pulse

0

20000

40000

60000

80000

200 400 600 800 1000 1200 1400 1600 1800 2000

Urea

KNO3

NH4NO3

KClO3

Remote Raman at 430 meters1 s detection time, daytime

Raman Shift (cm-1)

Inte

nsity

(Cou

nts)

Raman Shift (cm-1)

Inte

nsity

(Cou

nts)

AT= 81%

B54%

C18%

D5.6%

E1.7%

A: borosilicate glass vial (20 ml)

B: polypropylene (PP) vial (30 ml)

C: high-density polyethylene (HDPE) bottle (60 ml)

E: dark brown glass bottle (500 ml)

D: amber glass bottle (75 ml)

Water bottle Bubble wraps containing 20 ml glass vialsHDPE

Standoff Raman (532 nm) detection through sealed containers

0

5

10

15

20

25

30

500 1000 1500 2000 2500 3000 3500

AN in brown glass bottle

AN in PP bottle

AN in HDPE bottle

x 5

NH4NO3, single pulse excitation, 10 m

715

168

1043

1287

Raman Shift (cm-1)

Inte

nsity

(Cou

nts x

104 )

1418

3137

Single pulse Raman detection of Ammonium Nitrateat 10 m distance through sealed bottles

* 3 as measured spectra shown for each target

532 nm, 55 mJ/pulse, gate width 100 ns, slit 50 µm

0

10

20

30

40

500 1000 1500 2000 2500 3000 3500

AN hidden in bubble wrap

10 m, 1 s

715

168

1043

1287

Raman Shift (cm-1)

Inte

nsity

(Cou

nts x

104 )

3137

bubble wrap only

Raman detection of hidden glass vial of Ammonium Nitratethrough plastic bubble wrap

* 5 as-measured spectra shown

532 nm, 55 mJ/pulse, 15 hz, gate width 100 ns, slit 50 µm

0

1

2

3

4

5

Raman Shift (cm-1)

Inte

nsity

(Cou

nts x

106 )

0

2

46

810

12

500 1000 1500 2000 2500

HDPE bottle

AN in HDPE bottle

Yellow tape (center)

Yellow tape (off set)

Raman detection of AN throughfluorescent label on HDPE bottle

10 m, 10 s

X 10

715

1043

532.5 – 612.7 nm

457.3 – 530.9 nm

604.1 – 697.9 nm

736.5 – 869.4 nm

645.2 – 745.7 nm

Wavelength Range

Raman+LIBS Spectrograph with 5 spectral imageson one ICCD detector

ICCD Image (1024 x 256 pixels)

Steel, at 9 m, 1 double pulse LIBS, Pulse separation 1 µs, 100 mJ/pulse, gate delay 1 µs, gate width 4 µs. ICCD Gain 25

0

2

4

6

8

10

12

14

500 550 600 650 700 750 800 850

Wavelength (nm)

Inte

nsity

(Cou

nts x

104 )

Gate delay 1 µs, Gate width 20 µs, ICCD gain 10%, Double pulse separation 1 µs, 100 mJ/pulse, spot size 1 mm (dia)There are small shot to shot variations.

Single pulse and double pulse LIBS spectra of Aluminum sheet at 9 m.

0

2

4

6

8

10

500 550 600 650 700 750 800 850

635 640 645 650 655 660

Al, O

M

n Mn

, K Mg

Ca

Na

Ca

Al

Ca

Ca

Ca

Ca

H

HAl

Al

AlC

aC

a N

K

O

Mg

O

Mg

Ca

Ca

Mn

Mg,

N

* Spectra showing good reproducibility (4 measurements shown)* LIBS signal enhancement in double pulse excitation

Wavelength (nm)

Inte

nsity

(Cou

nts x

104 )

Raman and Fluorescence Imaging LIDAR (RFI-LIDAR)

for sea mine detection

Ocean LIDAR (532 nm)

Issues:* No detection in the top 1-2 m surface layer* Glint problem* Signal from fishes, plants, air bubbles…

Single Shot Detection of AN inside HDPE plastic bottleat 2 m Seawater Depth with 532 nm Laser

0

50000

100000

150000

200000

250000

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Raman Shift (cm-1)

Inte

nsity

(Cou

nts)

*3 as-measured spectra shownA

N

AN

AN

Wat

er

Plas

tic

Sulfa

te

Wat

er

Single pulse excitation100 ns detection

0

50000

100000

150000

200000

250000

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Raman Shift (cm-1)

Inte

nsity

(Cou

nts)

*3 as-measured spectra shownA

N

AN

AN

Wat

er

Plas

tic

Sulfa

te

Wat

er

Single pulse excitation100 ns detection

* Can detect explosives in plastic bags underwater* Metals have no Raman signal

Detection of both opaque metal object and also the transparent plastic dish using the image contrast.

Raman ImageSingle pulse detection,detection time 300 ns

Detection in presence of bio-fluorescence Detection of oil spillOne drop (0.1 ml) of crude oil in 2000 ml of water (50 ppm)

•Oil film is few micron thick

Current projects:

1. NASA Mars2020 mission: Los Alamos National LabSuperCam Instrument

2. NASA EPSCoR: Standoff biofinder+Chemical analyzer

3. NASA PICASSO: Standoff Raman Line Scanner

4. NASA STTR: Q Peak Inc. : Small laser for remote Raman+LIBS (phase I)

5. ONR: Underwater Raman system

6. ONR (code 30): Long range (~km) Raman system (low cost drone)

Thank you.