Towards eye-safe standoff Raman imaging systems

Martin Glimtoft, Petra Bååth, Heikki Saari, Jussi Mäkynen, Antti Näsilä, Henric Östmark

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

12 Citations (Scopus)

Abstract

Standoff Raman imaging systems have shown the ability to detect single explosives particles. However, in many cases, the laser intensities needed restrict the applications where they can be safely used. A new generation imaging Raman system has been developed based on a 355 nm UV laser that, in addition to eye safety, allows discrete and invisible measurements. Non-dangerous exposure levels for the eye are several orders of magnitude higher in UVA than in the visible range that previously has been used. The UV Raman system has been built based on an UV Fabry-Perot Interferometer (UV-FPI) developed by VTT. The design allows for precise selection of Raman shifts in combination with high out-of-band blocking. The stable operation of the UV-FPI module under varying environmental conditions is arranged by controlling the temperature of the module and using a closed loop control of the FPI air gap based on capacitive measurement. The system presented consists of a 3rd harmonics Nd:YAG laser with 1.5 W average output at 1000 Hz, a 200 mm Schmidt-Cassegrain telescope, UV-FPI filter and an ICCD camera for signal gating and detection. The design principal leads to a Raman spectrum in each image pixel. The system is designed for field use and easy manoeuvring. Preliminary results show that in measurements of <60 s on 10 m distance, single AN particles of <300 μm diameter can be identified.
Original languageEnglish
Title of host publicationProceedings of SPIE
Subtitle of host publicationVolume 9072, Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XIX, 2014
PublisherInternational Society for Optics and Photonics SPIE
Number of pages11
Volume9072
ISBN (Print)978-1-6284-1009-9
DOIs
Publication statusPublished - 2014
MoE publication typeA4 Article in a conference publication
EventSPIE Defense + Security - Baltimore, Maryland, United States
Duration: 5 May 20149 May 2014

Publication series

SeriesProceedings of SPIE
Volume9072
ISSN0277-786X

Conference

ConferenceSPIE Defense + Security
CountryUnited States
CityBaltimore, Maryland
Period5/05/149/05/14

Fingerprint

Fabry-Perot interferometers
modules
ultraviolet lasers
YAG lasers
safety
pixels
cameras
telescopes
Raman spectra
harmonics
filters
output
shift
air
lasers
temperature

Keywords

  • hyperspectral sensors
  • Raman imaging
  • Fabry-Perot interferometer
  • Piezo actuators

Cite this

Glimtoft, M., Bååth, P., Saari, H., Mäkynen, J., Näsilä, A., & Östmark, H. (2014). Towards eye-safe standoff Raman imaging systems. In Proceedings of SPIE: Volume 9072, Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XIX, 2014 (Vol. 9072). International Society for Optics and Photonics SPIE. Proceedings of SPIE, Vol.. 9072 https://doi.org/10.1117/12.2049676
Glimtoft, Martin ; Bååth, Petra ; Saari, Heikki ; Mäkynen, Jussi ; Näsilä, Antti ; Östmark, Henric. / Towards eye-safe standoff Raman imaging systems. Proceedings of SPIE: Volume 9072, Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XIX, 2014. Vol. 9072 International Society for Optics and Photonics SPIE, 2014. (Proceedings of SPIE, Vol. 9072).
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abstract = "Standoff Raman imaging systems have shown the ability to detect single explosives particles. However, in many cases, the laser intensities needed restrict the applications where they can be safely used. A new generation imaging Raman system has been developed based on a 355 nm UV laser that, in addition to eye safety, allows discrete and invisible measurements. Non-dangerous exposure levels for the eye are several orders of magnitude higher in UVA than in the visible range that previously has been used. The UV Raman system has been built based on an UV Fabry-Perot Interferometer (UV-FPI) developed by VTT. The design allows for precise selection of Raman shifts in combination with high out-of-band blocking. The stable operation of the UV-FPI module under varying environmental conditions is arranged by controlling the temperature of the module and using a closed loop control of the FPI air gap based on capacitive measurement. The system presented consists of a 3rd harmonics Nd:YAG laser with 1.5 W average output at 1000 Hz, a 200 mm Schmidt-Cassegrain telescope, UV-FPI filter and an ICCD camera for signal gating and detection. The design principal leads to a Raman spectrum in each image pixel. The system is designed for field use and easy manoeuvring. Preliminary results show that in measurements of <60 s on 10 m distance, single AN particles of <300 μm diameter can be identified.",
keywords = "hyperspectral sensors, Raman imaging, Fabry-Perot interferometer, Piezo actuators",
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Glimtoft, M, Bååth, P, Saari, H, Mäkynen, J, Näsilä, A & Östmark, H 2014, Towards eye-safe standoff Raman imaging systems. in Proceedings of SPIE: Volume 9072, Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XIX, 2014. vol. 9072, International Society for Optics and Photonics SPIE, Proceedings of SPIE, vol. 9072, SPIE Defense + Security, Baltimore, Maryland, United States, 5/05/14. https://doi.org/10.1117/12.2049676

Towards eye-safe standoff Raman imaging systems. / Glimtoft, Martin; Bååth, Petra; Saari, Heikki; Mäkynen, Jussi; Näsilä, Antti; Östmark, Henric.

Proceedings of SPIE: Volume 9072, Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XIX, 2014. Vol. 9072 International Society for Optics and Photonics SPIE, 2014. (Proceedings of SPIE, Vol. 9072).

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

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AU - Glimtoft, Martin

AU - Bååth, Petra

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AU - Näsilä, Antti

AU - Östmark, Henric

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N2 - Standoff Raman imaging systems have shown the ability to detect single explosives particles. However, in many cases, the laser intensities needed restrict the applications where they can be safely used. A new generation imaging Raman system has been developed based on a 355 nm UV laser that, in addition to eye safety, allows discrete and invisible measurements. Non-dangerous exposure levels for the eye are several orders of magnitude higher in UVA than in the visible range that previously has been used. The UV Raman system has been built based on an UV Fabry-Perot Interferometer (UV-FPI) developed by VTT. The design allows for precise selection of Raman shifts in combination with high out-of-band blocking. The stable operation of the UV-FPI module under varying environmental conditions is arranged by controlling the temperature of the module and using a closed loop control of the FPI air gap based on capacitive measurement. The system presented consists of a 3rd harmonics Nd:YAG laser with 1.5 W average output at 1000 Hz, a 200 mm Schmidt-Cassegrain telescope, UV-FPI filter and an ICCD camera for signal gating and detection. The design principal leads to a Raman spectrum in each image pixel. The system is designed for field use and easy manoeuvring. Preliminary results show that in measurements of <60 s on 10 m distance, single AN particles of <300 μm diameter can be identified.

AB - Standoff Raman imaging systems have shown the ability to detect single explosives particles. However, in many cases, the laser intensities needed restrict the applications where they can be safely used. A new generation imaging Raman system has been developed based on a 355 nm UV laser that, in addition to eye safety, allows discrete and invisible measurements. Non-dangerous exposure levels for the eye are several orders of magnitude higher in UVA than in the visible range that previously has been used. The UV Raman system has been built based on an UV Fabry-Perot Interferometer (UV-FPI) developed by VTT. The design allows for precise selection of Raman shifts in combination with high out-of-band blocking. The stable operation of the UV-FPI module under varying environmental conditions is arranged by controlling the temperature of the module and using a closed loop control of the FPI air gap based on capacitive measurement. The system presented consists of a 3rd harmonics Nd:YAG laser with 1.5 W average output at 1000 Hz, a 200 mm Schmidt-Cassegrain telescope, UV-FPI filter and an ICCD camera for signal gating and detection. The design principal leads to a Raman spectrum in each image pixel. The system is designed for field use and easy manoeuvring. Preliminary results show that in measurements of <60 s on 10 m distance, single AN particles of <300 μm diameter can be identified.

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KW - Piezo actuators

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DO - 10.1117/12.2049676

M3 - Conference article in proceedings

SN - 978-1-6284-1009-9

VL - 9072

T3 - Proceedings of SPIE

BT - Proceedings of SPIE

PB - International Society for Optics and Photonics SPIE

ER -

Glimtoft M, Bååth P, Saari H, Mäkynen J, Näsilä A, Östmark H. Towards eye-safe standoff Raman imaging systems. In Proceedings of SPIE: Volume 9072, Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XIX, 2014. Vol. 9072. International Society for Optics and Photonics SPIE. 2014. (Proceedings of SPIE, Vol. 9072). https://doi.org/10.1117/12.2049676