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A multispectral camera records image data in various wavelengths across the electromagnetic spectrum to acquire additional information that a conventional camera fails to capture. With the advent of high-resolution image sensors and color filter technologies, multispectral imagers in the visible wavelengths have become popular with increasing commercial viability in the last decade. However, multispectral imaging in longwave infrared (LWIR, 8–14 µm) is still an emerging area due to the limited availability of optical materials, filter technologies, and high-resolution sensors. Images from LWIR multispectral cameras can capture emission spectra of objects to extract additional information that a human eye fails to capture and thus have important applications in precision agriculture, forestry, medicine, and object identification. In this work, we experimentally demonstrate an LWIR multispectral image sensor with three wavelength bands using optical elements made of an aluminum (Al)-based plasmonic filter array sandwiched in germanium (Ge). To realize the multispectral sensor, the filter arrays are then integrated into a three-dimensional (3D) printed wheel stacked on a low-resolution monochrome thermal sensor. Our prototype device is calibrated using a blackbody and its thermal output has been enhanced with computer vision methods. By applying a state-of-the-art deep learning method, we have also reconstructed multispectral images to a better spatial resolution. Scientifically, our work demonstrates a versatile spectral thermography technique for detecting target signatures in the LWIR range and other advanced spectral analyses.


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Longwave infrared multispectral image sensor system using aluminum-germanium plasmonic filter arrays

Show Author's information Noor E Karishma Shaik1( )Bryce Widdicombe1Dechuan Sun1Sam E John2Dongryeol Ryu3Ampalavanapillai Nirmalathas1Ranjith R Unnithan1( )
Department of Electrical and Electronic Engineering, University of Melbourne, Parkville, VIC 3010, Australia
Department of Biomedical Engineering, University of Melbourne, Parkville, VIC 3010, Australia
Department of Infrastructure Engineering, University of Melbourne, Parkville, VIC 3010, Australia

Abstract

A multispectral camera records image data in various wavelengths across the electromagnetic spectrum to acquire additional information that a conventional camera fails to capture. With the advent of high-resolution image sensors and color filter technologies, multispectral imagers in the visible wavelengths have become popular with increasing commercial viability in the last decade. However, multispectral imaging in longwave infrared (LWIR, 8–14 µm) is still an emerging area due to the limited availability of optical materials, filter technologies, and high-resolution sensors. Images from LWIR multispectral cameras can capture emission spectra of objects to extract additional information that a human eye fails to capture and thus have important applications in precision agriculture, forestry, medicine, and object identification. In this work, we experimentally demonstrate an LWIR multispectral image sensor with three wavelength bands using optical elements made of an aluminum (Al)-based plasmonic filter array sandwiched in germanium (Ge). To realize the multispectral sensor, the filter arrays are then integrated into a three-dimensional (3D) printed wheel stacked on a low-resolution monochrome thermal sensor. Our prototype device is calibrated using a blackbody and its thermal output has been enhanced with computer vision methods. By applying a state-of-the-art deep learning method, we have also reconstructed multispectral images to a better spatial resolution. Scientifically, our work demonstrates a versatile spectral thermography technique for detecting target signatures in the LWIR range and other advanced spectral analyses.

Keywords: infrared plasmonics, thermal optics, germanium (Ge), aluminum (Al), longwave infrared (LWIR) multispectral system

References(45)

[1]

Akula, A.; Ghosh, R.; Sardana, H. K. Thermal imaging and its application in defence systems. AIP Conf. Proc. 2011, 1391, 333–335.

[2]

Manolakis, D.; Steven, G.; DiPietro, R. S. Long-wave infrared hyperspectral remote sensing of chemical clouds: A focus on signal processing approaches. IEEE Signal Process. Mag. 2014, 31, 120–141.

[3]
Tratt, D. M.; Buckland, K. N.; Keim, E. R.; Johnson, P. D. Urban-industrial emissions monitoring with airborne longwave-infrared hyperspectral imaging. In 8th Workshop on Hyperspectral Image and Signal Processing: Evolution in Remote Sensing (WHISPERS), Los Angeles, 2016, pp 1–5.
[4]
George, T.; Gulati, S.; Martin, S.; Nozaki, S. Comparison of mid wave infrared (MWIR) and long wave infrared (LWIR) imagery for precision agriculture applications. In 2019 IEEE Aerospace Conference, Big Sky, 2019, pp 1–15.
[5]
The correct material for infrared (IR) applications [Online]. https://www.edmundoptics.com.au/knowledge-center/application-notes/optics/the-correct-material-for-infrared-applications/ (accessed September 21, 2022)
[6]

Talghader, J. J.; Gawarikar, A. S.; Shea, R. P. Spectral selectivity in infrared thermal detection. Light:Sci. Appl. 2012, 1, e24.

[7]

Tran, C. D. Infrared multispectral imaging: Principles and instrumentation. Appl. Spectrosc. Rev. 2003, 38, 133–153.

[8]

Manolakis, D.; Pieper, M.; Truslow, E.; Lockwood, R.; Weisner, A.; Jacobson, J.; Cooley, T. Longwave infrared hyperspectral imaging: Principles, progress, and challenges. IEEE Geosci. Remote Sens. Mag. 2019, 7, 72–100.

[9]
Gagnon, M. A.; Jahjah, K. A.; Marcotte, F.; Tremblay, P.; Farley, V.; Guyot, É.; Chamberland, M. Time-resolved thermal infrared multispectral imaging of gases and minerals. In Proceedings of the SPIE 9249, Electro-Optical and Infrared Systems: Technology and Applications XI, Amsterdam, 2014, pp 92490U.
[10]
Schreer, O.; Zettner, J.; Spellenberg, B.; Schmidt, U.; Danner, A.; Peppermueller, C.; Saenz, M. L.; Hierl, T. Multispectral high-speed midwave infrared imaging system. In Proceedings of the SPIE 5406, Infrared Technology and Applications XXX, Orlando, 2004, pp 249–257.
[11]

Takagawa, Y.; Ogawa, S.; Kimata, M. Detection wavelength control of uncooled infrared sensors using two-dimensional lattice plasmonic absorbers. Sensors 2015, 15, 13660–13669.

[12]

Wang, A.; Dan, Y. P. Mid-infrared plasmonic multispectral filters. Sci. Rep. 2018, 8, 11257.

[13]
Genet, C.; Ebbesen, T. W. Light in tiny holes. Nanosci. Technol. 2009, 445, 39–46.
[14]

Meinzer, N.; Barnes, W. L.; Hooper, I. R. Plasmonic meta-atoms and metasurfaces. Nat. Photonics 2014, 8, 889–898.

[15]

Bouchon, P.; Pardo, F.; Portier, B.; Ferlazzo, L.; Ghenuche, P.; Dagher, G.; Dupuis, C.; Bardou, N.; Haïdar, R.; Pelouard, J. L. Total funneling of light in high aspect ratio plasmonic nanoresonators. Appl. Phys. Lett. 2011, 98, 191109.

[16]

Hao, J. M.; Wang, J.; Liu, X. L.; Padilla, W. J.; Zhou, L.; Qiu, M. High performance optical absorber based on a plasmonic metamaterial. Appl. Phys. Lett. 2010, 96, 251104.

[17]

Lapray, P. J.; Wang, X. B.; Thomas, J. B.; Gouton, P. Multispectral filter arrays: Recent advances and practical implementation. Sensors 2014, 14, 21626–21659.

[18]

He, X.; Liu, Y. J.; Ganesan, K.; Ahnood, A.; Beckett, P.; Eftekhari, F.; Smith, D.; Uddin, H.; Skafidas, E.; Nirmalathas, A. et al. A single sensor based multispectral imaging camera using a narrow spectral band color mosaic integrated on the monochrome CMOS image sensor. APL Photonics 2020, 5, 046104.

[19]

Monno, Y.; Kikuchi, S.; Tanaka, M.; Okutomi, M. A practical one-shot multispectral imaging system using a single image sensor. IEEE Trans. Image Process. 2015, 24, 3048–3059.

[20]

Burgos, S. P.; Yokogawa, S.; Atwater, H. A. Color imaging via nearest neighbor hole coupling in plasmonic color filters integrated onto a complementary metal-oxide semiconductor image sensor. ACS Nano 2013, 7, 10038–10047.

[21]
Pinton, N.; Grant, J.; Choubey, B.; Cumming, D.; Collins, S. Recent progress in plasmonic colour filters for image sensor and multispectral applications. In Proceedings of the SPIE 9884, Nanophotonics VI, Brussels, 2016, pp 988438.
[22]

Goetz, S.; Bauch, M.; Dimopoulos, T.; Trassl, S. Ultrathin sputter-deposited plasmonic silver nanostructures. Nanoscale Adv. 2020, 2, 869–877.

[23]

Chong, X. Y.; Li, E. W.; Squire, K.; Wang, A. X. On-chip near-infrared spectroscopy of CO2 using high resolution plasmonic filter array. Appl. Phys. Lett. 2016, 108, 221106.

[24]

Jang, W. Y.; Ku, Z.; Jeon, J.; Kim, J. O.; Lee, S. J.; Park, J.; Noyola, M. J.; Urbas, A. Experimental demonstration of adaptive infrared multispectral imaging using plasmonic filter array. Sci. Rep. 2016, 6, 34876.

[25]

Park, H.; Crozier, K. B. Multispectral imaging with vertical silicon nanowires. Sci. Rep. 2013, 3, 2460.

[26]

Gérard, D.; Gray, S. K. Aluminium plasmonics. J. Phys. D:Appl. Phys. 2015, 48, 184001.

[27]

Vetter, K. Recent developments in the fabrication and operation of germanium detectors. Annu. Rev. Nucl. Part. Sci. 2007, 57, 363–404.

[28]

Stanley, R. Plasmonics in the mid-infrared. Nat. Photonics 2012, 6, 409–411.

[29]

Mirnaziry, S. R.; Setayesh, A.; Abrishamian, M. S. Design and analysis of plasmonic filters based on stubs. J. Opt. Soc. Am. B 2011, 28, 1300–1307.

[30]

Shoji, T.; Tsuboi, Y. Plasmonic optical tweezers toward molecular manipulation: Tailoring plasmonic nanostructure, light source, and resonant trapping. J. Phys. Chem. Lett. 2014, 5, 2957–2967.

[31]

Ogawa, S.; Kimata, M. Wavelength- or polarization-selective thermal infrared detectors for multi-color or polarimetric imaging using plasmonics and metamaterials. Materials 2017, 10, 493.

[32]

Tsakmakidis, K. L.; Boyd, R. W.; Yablonovitch, E.; Zhang, X. Large spontaneous-emission enhancements in metallic nanostructures: Towards LEDs faster than lasers. Opt. Express 2016, 24, 17916–17927.

[33]

Yu, J. Y.; Ohtera, Y.; Yamada, H. Scattering-parameter model analysis of side-coupled plasmonic Fabry–Perot waveguide filters. Appl. Phys. A 2018, 124, 516.

[34]

Unnithan, R. R.; Sun, M.; He, X.; Balaur, E.; Minovich, A.; Neshev, D. N.; Skafidas, E.; Roberts, A. Plasmonic colour filters based on coaxial holes in aluminium. Materials 2017, 10, 383.

[35]
Shaik, N. E. K.; Weston, L.; Nirmalathas, A.; Unnithan, R. R. Aluminum plasmonics in thermal wavelengths for multispectral imaging. In 2020 Conference on Lasers and Electro-Optics (CLEO), San Jose, 2020, pp 1–2.
[36]
Craig, B.; Shrestha, V. R.; Meng, J. J.; Crozier, K. B. Experimental demonstration of mid-infrared computational spectroscopy with a plasmonic filter array. In 2018 Conference on Lasers and Electro-Optics (CLEO), San Jose, 2018, pp 1–2.
[37]

Tittl, A.; Michel, A. K. U.; Schäferling, M.; Yin, X. H.; Gholipour, B.; Cui, L.; Wuttig, M.; Taubner, T.; Neubrech, F.; Giessen, H. A switchable mid-infrared plasmonic perfect absorber with multispectral thermal imaging capability. Adv. Mater. 2015, 27, 4597–4603.

[38]

Lee, S. J.; Ku, Z.; Barve, A.; Montoya, J.; Jang, W. Y.; Brueck, S. R. J.; Sundaram, M.; Reisinger, A.; Krishna, S.; Noh, S. K. A monolithically integrated plasmonic infrared quantum dot camera. Nat. Commun. 2011, 2, 286.

[39]

Dao, T. D.; Ishii, S.; Yokoyama, T.; Sawada, T.; Sugavaneshwar, R. P.; Chen, K.; Wada, Y.; Nabatame, T.; Nagao, T. Hole array perfect absorbers for spectrally selective midwavelength infrared pyroelectric detectors. ACS Photonics 2016, 3, 1271–1278.

[40]

Dai, Q.; Rajasekharan, R.; Butt, H.; Qiu, X. H.; Amaragtunga, G.; Wilkinson, T. D. Ultrasmall microlens array based on vertically aligned carbon nanofibers. Small 2012, 8, 2501–2504.

[41]
Choi, Y.; Kim, N.; Hwang, S.; Kweon, I. S. Thermal image enhancement using convolutional neural network. In 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Daejeon, 2016, pp 223–230.
[42]

Mittal, A.; Soundararajan, R.; Bovik, A. C. Making a “completely blind” image quality analyzer. IEEE Signal Process. Lett. 2013, 20, 209–212.

[43]
Polyanskiy, M. Refractive index—optical constants of aluminum, Rakic, MediaWiki [Online]. https://refractiveindex.info/?shelf=mainbook=Alpage=Rakic (accessed Sep 13, 2018).
[44]
Wang, X. T.; Yu, K.; Wu, S. X.; Gu, J. J.; Liu, Y. H.; Dong, C.; Qiao, Y.; Loy, C. C. ESRGAN: Enhanced super-resolution generative adversarial networks. In Proceedings of the European Conference on Computer Vision, Munich, 2019, pp 63–79.
[45]
Agustsson, E.; Timofte, R. NTIRE 2017 challenge on single image super-resolution: Dataset and study. In Proceedings of the 2017 IEEE Conference on Computer Vision and Pattern Recognition Workshops, Honolulu, 2017, pp 1122–1131.
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Publication history

Received: 26 September 2022
Revised: 13 March 2023
Accepted: 14 March 2023
Published: 25 May 2023
Issue date: July 2023

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© The author(s) 2023

Acknowledgements

Acknowledgements

The numerical simulations were undertaken in the NCI National Facility in Canberra, Australia, which is supported by the Australian Commonwealth Government. This work was performed in part at the Melbourne Centre for Nanofabrication (MCN) in the Victorian Node of the Australian National Fabrication Facility (ANFF). This project received funding from the Linkage Grant from Australian Research Council (No. LP160101475). The authors thank Dr. Nandakishor Desai, Mr. Luke Weston and Assoc. Prof. Karim Seghouane for helpful discussions. NKS would like to additionally acknowledge the financial support provided by Melbourne Research Scholarship during PhD.

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Copyright: © 2023 by the author(s). This article is an open access article distributed under Creative Commons Attribution License (CC BY 4.0), visit https://creativecommons.org/licenses/by/4.0/.

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