Remote Raman & Fluorescence Capabilities for Chemical Detection at University of Hawaii Anupam Misra Shiv Sharma HIGP, SOEST, Univ. of Hawaii * Daytime Operation * Long Detection Range (no sample collection) * Fast Response * Portable 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)
What is Raman spectroscopy? Why need Raman spectra? Prof. Sir C. V. Raman Nobel Prize 193 Raman spectra Laser Beam splitter Sample Vibrational modes of molecules ω = µ k Spectrograph CCD Notch Filter Depends on atomic mass, bond lengths, bond strength, configuration, etc Unique spectrum for each molecule * Raman Fingerprints: Chemical detection with very high confidence level
Example of Raman Spectra: Raman spectroscopy can distinguish between very similar chemicals 623 77 12 124 1445 163 Ethyl benzene 2933 353 3 25 1347 Intensity (counts) 2 15 1 5 66 853 13 119 992 1178 1588 1584 Nitrobenzene Benzene 5 1 15 2 25 3 35 4 379 362 N O O ω = µ k c = f λ Always the same unique spectrum for a chemical!!!
* Good technique for detecting chemicals you don t want to handle. * No sample preparation (Chemical waste sites, airport) Single pulse Raman detection of Conc. Sulfuric Acid from 1 m 12 1 913 H 2 SO 4, single pulse excitation, 1 m * 5 as-measured spectra shown Intensity (Counts) 8 6 4 417 56 147 1148 338 2 137 5 1 15 2 25 3 35 4 45 55 mj/pulse, gate width 1 ns, slit 5 µm
Single Pulse Raman from 12 m Detection time = 1 ns System to sample view System Front view Integrated Remote Raman+LIBS System Key Components: (a) Dual Pulse Laser, 532 nm, 15 Hz, 1 mj/pulse (b) One gated intensified detector (ICCD) (c) One high resolution, high throughput spectrograph (d) 8-inch Telescope
Single shot Raman detection of Potassium chlorate & Potassium perchlorate at 12 m * Good reproducibility (showing 5 spectra as measured) * Good quality (High S/N) 25 Target at 12 m Single shot excitation 939 Intensity (Counts x1 4 ) 2 15 1 5 KClO 3 KClO 4 487 463 619 629 942 924 978 187 1125 2 4 6 8 1 12 14 16 18 1 mj, 532 nm, 5 µm slit, laser spot size 1 cm (diameter).
Single shot Raman detection of Ammonium Nitrate & Potassium Nitrate at 12 m distance through sealed glass bottles * Good reproducibility (showing 5 measurements- as measured) Intensity (Counts x1 4 ) 3 25 2 15 1 Target at 12 m Single shot excitation Detection time =.5 µs 715 143 15 NH 4 NO 3 KNO 3 12 14 16 18 1345 136 143 KNO 3 15 5 171 715 1287 1418 NH 4 NO 3 2 4 6 8 1 12 14 16 18
Single shot detection of 8% TNT on silica (NESTT sample) at 12 m distance * Good reproducibility (showing 5 measurements- as measured) 2 8% TNT on silica at 12 m Single shot excitation 1366 Intensity (Counts x1 3 ) 15 1 Detection time =.5 µs 823 94 1211 1535 1556 (O 2 ) 1619 5 6 8 1 12 14 16 18 2
Single shot Raman detection of Urea and Sugar at 12 m distance through sealed glass bottles * Good reproducibility (showing 5 measurements- as measured) 1 Target at 12 m Single shot excitation 111 Intensity (Counts x1 4 ) 8 6 4 2 175 42 548 54 641 85 922 138 1178 1126 1162 1239 Urea 1349 1464 1462 1541 165 Sugar 2 4 6 8 1 12 14 16 18 1 mj, 532 nm, 5 µm slit, laser spot size 1 cm (diameter).
Significant improvement in Raman signal (1 s) * Good reproducibility (5 measurements shown) 4 Gypsum at 12 m 18 Intensity (Counts) 3 2 1 1136 414 494 62 671 1 s (= 15 pulses) 1 pulse 2 4 6 8 1 12 14
Raman Detection of Mixed grains of chemicals at 12 m distance * 1 s detection time * Good reproducibility (5 measurements shown) Intensity (Counts x 1 4 ) 1 8 6 4 153 S 185 S 219 S 248 S 44 S 473 S 513 Nap 715 AN 763 Nap 121 Nap 144 AN 1382 Nap 1465 Nap Target at 12 m 1578 Nap S = Sulfur Nap = Naphthalene AN = Ammonium Nitrate 2 2 4 6 8 1 12 14 16 18 2 1 mj/pulse, 15 Hz, 532 nm, 5 micron slit, laser spot size 1 cm.
Detection of atmosphere, target mineral and both (as measured spectra) Target (Gypsum CaSO 4.2H 2 O) at 5 m * 8 1556 O 2 2331 N 2 3652 H 2 O Atmosphere Intensity (counts) 6 4 414 493 619 671 17 1136 345 3496 Target 2 Target + atmosphere 5 1 15 2 25 3 35 4 45
2 compact Raman+LIBS system Minerals at 9 m, 1 s (3 measurements shown for each mineral) Intensity (Counts x 1 6 ) 3 25 2 15 177 153 219 3 438 473 417 464 499 69 628 676 726 117 198 1129 116 1442 Dolomite Sulfur Anhydrite 176 1 26 264 355 394 694 8 116 Quartz 5 143 396 515 638 Anatase 2 4 6 8 1 12 14 16 18 532 nm, 3 mj/pulse
Remote Raman at 43 meters 1 s detection time, daytime 8 6 NH 4 NO 3 Intensity (Counts) 4 2 KNO 3 KClO 3 Urea 2 4 6 8 1 12 14 16 18 2
Standoff Raman (532 nm) detection through sealed containers A: borosilicate glass vial (2 ml) B: polypropylene (PP) vial (3 ml) C: high-density polyethylene (HDPE) bottle (6 ml) D: amber glass bottle (75 ml) A T= 81% B 54% C 18% D 5.6% E 1.7% E: dark brown glass bottle (5 ml) HDPE Water bottle Bubble wraps containing 2 ml glass vials
Single pulse Raman detection of Ammonium Nitrate at 1 m distance through sealed bottles * 3 as measured spectra shown for each target 3 143 NH 4 NO 3, single pulse excitation, 1 m Intensity (Counts x1 4 ) 25 2 15 1 168 715 1287 1418 AN in HDPE bottle AN in PP bottle 3137 5 AN in brown glass bottle 5 1 15 2 25 3 35 x 5 532 nm, 55 mj/pulse, gate width 1 ns, slit 5 µm
Raman detection of hidden glass vial of Ammonium Nitrate through plastic bubble wrap * 5 as-measured spectra shown 4 143 1 m, 1 s Intensity (Counts x1 4 ) 3 2 1 168 715 1287 AN hidden in bubble wrap 3137 bubble wrap only 5 1 15 2 25 3 35 532 nm, 55 mj/pulse, 15 hz, gate width 1 ns, slit 5 µm
Raman detection of AN through fluorescent label on HDPE bottle 5 4 1 m, 1 s 143 Intensity (Counts x1 6 ) 3 2 1 12 1 8 6 4 2 715 AN in HDPE bottle HDPE bottle Yellow tape (center) Yellow tape (off set) X 1 5 1 15 2 25
Raman+LIBS Spectrograph with 5 spectral images on one ICCD detector ICCD Image (124 x 256 pixels) Wavelength Range 532.5 612.7 nm 457.3 53.9 nm 64.1 697.9 nm 736.5 869.4 nm 645.2 745.7 nm 14 Intensity (Counts x 1 4 ) 12 1 8 6 4 2 5 55 6 65 7 75 8 85 Wavelength (nm) Steel, at 9 m, 1 double pulse LIBS, Pulse separation 1 µs, 1 mj/pulse, gate delay 1 µs, gate width 4 µs. ICCD Gain 25
Single pulse and double pulse LIBS spectra of Aluminum sheet at 9 m. Intensity (Counts x 1 4 ) 1 8 6 4 2 * Spectra showing good reproducibility (4 measurements shown) * LIBS signal enhancement in double pulse excitation Al, O Mn Mn, K Mg Mg, N Ca Ca Na Ca Ca Mn Al Mg Ca H Al Al Al Ca Ca Mg O Ca Ca Ca H 635 64 645 65 655 66 N K O 5 55 6 65 7 75 8 85 Wavelength (nm) Gate delay 1 µs, Gate width 2 µs, ICCD gain 1%, Double pulse separation 1 µs, 1 mj/pulse, spot size 1 mm (dia) There are small shot to shot variations.
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 bottle at 2 m Seawater Depth with 532 nm Laser *3 as-measured spectra shown 25 Single pulse excitation 1 ns detection Water Intensity (Counts) 2 15 1 AN 5 AN Sulfate AN Water Plastic 5 1 15 2 25 3 35 4 45 * 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 Image Single pulse detection, detection time 3 ns
Detection in presence of bio-fluorescence Detection of oil spill One drop (.1 ml) of crude oil in 2 ml of water (5 ppm) Oil film is few micron thick
Current projects: 1. NASA Mars22 mission: Los Alamos National Lab SuperCam 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 3): Long range (~km) Raman system (low cost drone) Thank you.