Subsurface spectroscopy of heterogeneous materials using optical wavefront shaping

Journal Article · 26 September 2023 · AIP Conference Proceedings

DOI: https://doi.org/10.1063/12.0020576 · OSTI ID:2305479

Anderson, Benjamin R. ^[1]; Gese, Natalie J. ^[1]; Eilers, Hergen ^[1]

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1. Washington State University, Spokane, WA (United States)

Plastic-bonded explosives and propellants consist of energetic molecular crystals embedded in a polymer matrix that also includes additives, such as taggants, plasticizers, grit, antioxidants, etc. Furthermore, this heterogeneous composition renders these materials optically opaque, limiting optical characterization techniques (e.g., Raman spectroscopy) to probing chemical reactions at the sur-face. However, many reactions of interest are believed to occur inside the material where current optical techniques can not probe. To address this challenge, we have developed a new optical technique that utilizes feedback assisted wavefront shaping (using spatial light modulators) to focus probe light inside a heterogeneous material, such that we can perform subsurface spectroscopy. Recently, we demonstrated this technique by monitoring subsurface photodegradation and thermal degradation of Eu-doped molecular crystals using both fluorescence and Raman spectroscopy. Based off these successes we are now looking into improvements to this technique to allow for greater time resolution, including replacing our spatial light modulators with fast digital mirror devices, using ns optical phase conjugation, and self-healing optical beams.

• Research Organization: Washington State Univ., Pullman, WA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Office of Defense Programs (DP)
• Grant/Contract Number: NA0004083
• OSTI ID: 2305479
• Journal Information: AIP Conference Proceedings, Vol. 2844, Issue 1; Conference: Shock Compression of Condensed Matter - 2022: Proceedings of the Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter, Anaheim, CA (United States), 10-15 Jul 2022; ISSN 0094-243X
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English