A matrix approach for optical detection and imaging through highly scattering media (Conference Presentation)

2016 ◽  
Author(s):  
Amaury Badon ◽  
Dayan Li ◽  
Geoffroy Lerosey ◽  
Claude Boccara ◽  
Mathias Fink ◽  
...  
Keyword(s):  
Optical Detection ◽  
Matrix Approach ◽  
Scattering Media

Matrix approach of adaptive optics for the imaging of scattering media

2021 ◽  
Author(s):  
Ulysse Najar ◽  
Paul Balondrade ◽  
Victor Barolle ◽  
Laura A. Cobus ◽  
Claude A. Boccara ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Matrix Approach ◽  
Scattering Media

Optical Detection of Tracer Species in Strongly Scattering Media

2015 ◽  
Vol 69 (3) ◽  
pp. 363-369
Author(s):  
Eric M. Brauser ◽  
Peter E. Rose ◽  
John D. McLennan ◽  
Michael H. Bartl
Keyword(s):  
Optical Detection ◽  
Scattering Media

scholarly journals Reflection Matrix Approach for Quantitative Imaging of Scattering Media

2020 ◽  
Vol 10 (2) ◽  
Author(s):  
William Lambert ◽  
Laura A. Cobus ◽  
Mathieu Couade ◽  
Mathias Fink ◽  
Alexandre Aubry
Keyword(s):  
Quantitative Imaging ◽  
Matrix Approach ◽  
Scattering Media ◽  
Reflection Matrix

Passive seismic matrix imaging of La Soufrière of Guadeloupe volcano

2021 ◽  
Author(s):  
Elsa Giraudat ◽  
Arnaud Burtin ◽  
Alexandre Aubry
Keyword(s):  
Seismic Noise ◽  
Seismic Imaging ◽  
Physical Parameters ◽  
Matrix Approach ◽  
Scattering Media ◽  
Reflection Matrix ◽  
Rough Approximation ◽  
Passive Seismic ◽  
Phase Distortions ◽  
Distortion Matrix

<p>Volcanoes are among the most challenging media for seismic imaging given their highly localized and abrupt variations in physical parameters, extreme landforms, fractures, and the presence of magma and other fluids. Because of this high level of heterogeneity and the resulting difficulty to access the wave velocity distribution in the medium, reflection seismic imaging of volcanoes usually suffers from a loss of resolution and contrast. Here, we present a passive seismic imaging technique applied to the case of La Soufrière of Guadeloupe volcano. Inspired by previous works in optics (Badon <em>et al</em>., 2020), in acoustics (Lambert <em>et al</em>., 2020), and recently introduced in seismology (Touma <em>et al</em>., 2020), this technique relies on a matrix approach of passive reflection imaging, which requires only a rough approximation about the medium background velocity. This makes it robust even applied to extreme environments as volcanoes or fault zones. In this approach, the Green’s functions between an array of 76 geophones placed at the surface of the volcano are retrieved by cross-correlation of ambient seismic noise. This set of 2850 inter-element impulse responses forms a reflection matrix. Focusing operations are applied to this reflection matrix at emission and reception to project it in–depth. The focusing process allows to extract body wave components from seismic noise and thus, to retrieve information about reflectivity of in-depth structures. However, at this point, reflectivity images of the subsurface still suffer from phase distortions induced by long-range variations of the seismic velocity. This results in blurred images and hinders appropriate imaging. To overcome these issues, a novel operator is introduced: the distortion matrix. This operator is derived from the focused reflection matrix and connects any point in the medium with the distortion that a wavefront emitted from that point would experience due to heterogeneity. A time-reversal analysis of the distortion matrix allows to retrieve aberrations phase laws and hence to compensate for phase distortions. This correction enables to recover 3D-images of the volcano’s subsurface for the first 10km below the summit with optimized contrast and with an increased resolution. Interestingly, the restored resolution is even at least one half below the diffraction limit imposed by the geophone array angular aperture at the surface. The obtained gain in resolution and contrast allows to unveil internal structures of La Soufrière as hypothetical volcanic vents, magma reservoirs and lateral drainage conduits.</p><p><strong>References</strong></p><p>[Badon <em>et al</em>., 2020] Badon, A., Barolle, V., Irsch, K., Boccara, A. C., Fink, M., and Aubry, A. (2020). Distortion matrix concept for deep optical imaging in scattering media. <em>Science Advances,</em> 6(30).</p><p>[Lambert <em>et al.</em>, 2020] Lambert, W., Cobus, L. A., Frappart, T., Fink, M., and Aubry, A. (2020). Distortion matrix approach for ultrasound imaging of random scattering media. <em>Proceedings of the National Academy of Sciences,</em> 117(26):14645-14656.</p><p>[Touma<em> et al.</em>, 2020] Touma, R., Blondel, T., Derode, A., Campillo, M., & Aubry, A. (2020). A Distortion Matrix Framework for High-Resolution Passive Seismic 3D Imaging: Application to the San Jacinto Fault Zone, California.<em> arXiv preprint arXiv</em>:2008.01608.</p>

OPTICAL DETECTION OF 1D FERROMAGNETISM IN CsNiF3

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-1447-C8-1448
Author(s):  
T. Tsuboi ◽  
R. Laiho
Keyword(s):  
Optical Detection
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