Retrieving time-dependent Green’s functions in optics with low-coherence interferometry

Badon, Amaury; Lerosey, Geoffroy; Boccara, Albert Claude; Fink, Mathias; Aubry, Alexandre

doi:10.1364/cleo_qels.2015.fw1c.1

Cited by 8 publications

(10 citation statements)

References 5 publications

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“…To reach a better axial resolution, the measurement of the reflection matrix can be made under a simple white light illumination. A recent study has actually demonstrated the passive measurement of the time-dependent point-to-point reflection matrix from an incoherent illumination [43]. As already demonstrated in full-field OCT [42], the temporal incoherence of the white-light source would provide an excellent axial resolution (δz ∼1 µm).…”

Section: Discussionmentioning

confidence: 86%

Smart optical coherence tomography for ultra-deep imaging through highly scattering media

Badon

Lerosey

et al. 2017

Imaging and Applied Optics 2017 (3D, AIO, COSI, IS, MATH, pcAOP)

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Multiple scattering of waves in disordered media is a nightmare whether it be for detection or imaging purposes. The best approach so far to get rid of multiple scattering is optical coherence tomography. It basically combines confocal microscopy and coherence time-gating to discriminate ballistic photons from a predominant multiple scattering background. Nevertheless, the imaging depth range remains limited to 1 mm at best in human soft tissues. Here we propose a matrix approach of optical imaging to push back this fundamental limit. By combining a matrix discrimination of ballistic waves and iterative time-reversal, we show both theoretically and experimentally an extension of the imaging-depth limit by at least a factor two compared to optical coherence tomography. In particular, the reported experiment demonstrates imaging through a strongly scattering layer from which only one reflected photon over 1000 billion is ballistic. This approach opens a new route towards ultra-deep tissue imaging.

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Section: Discussionmentioning

confidence: 86%

Smart optical coherence tomography for ultra-deep imaging through highly scattering media

Badon

Lerosey

et al. 2017

Imaging and Applied Optics 2017 (3D, AIO, COSI, IS, MATH, pcAOP)

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“…Another possibility would be to switch from a scanning to a full-field illumination scheme. A measurement of the coherent reflection matrix R can be performed under a spatially incoherent illumination (46,47). This full-field configuration would allow to record the R− and D-matrices over millimetric volumes in a moderate acquisition time.…”

Section: Discussionmentioning

confidence: 99%

Distortion matrix concept for deep optical imaging in scattering media

Badon,

Barolle,

Irsch

et al. 2019

Preprint

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In optical imaging, light propagation is affected by the inhomogeneities of the medium. Sample-induced aberrations and multiple scattering can strongly degrade the image resolution and contrast. Based on a dynamic correction of the incident and/or reflected wave-fronts, adaptive optics has been employed to compensate for those aberrations. However, it mainly applies to spatiallyinvariant aberrations or to thin aberrating layers. Here, we propose a global and non-invasive approach based on the distortion matrix concept. This matrix basically connects any focusing point of the image with the distorted part of its wave-front in reflection. A time-reversal and entropy analysis of the distortion matrix allows to correct for high-order aberrations and forward multiple scattering over multiple isoplanatic areas. Proof-of-concept experiments are performed through biological tissues and an opaque cornea. We demonstrate a Strehl ratio enhancement up to 2500 and recover a diffraction-limited resolution until a depth of ten scattering mean free paths.

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“…It is now well-known that the Green's function of the wave equation can be estimated from the cross correlation of the signals emitted by ambient noise sources and recorded by passive sensors [3,4,6,10,7,11,19,22,24]. In a homogeneous medium and when the source of the waves is a space-time stationary random field that is also delta-correlated in space and time, it has been shown [21,17] that the derivative of the cross correlation of the signals recorded by two sensors is proportional to the symmetrized Green's function between the sensors.…”

Section: Introductionmentioning

confidence: 99%

Ambient noise correlation-based imaging with moving sensors

Fink¹,

Garnier²

2017

Inverse Problems &Amp; Imaging

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Waves can be used to probe and image an unknown medium. Passive imaging uses ambient noise sources to illuminate the medium. This paper considers passive imaging with moving sensors. The motivation is to generate large synthetic apertures, which should result in enhanced resolution. However Doppler effects and lack of reciprocity significantly affect the imaging process. This paper discusses the consequences in terms of resolution and it shows how to design appropriate imaging functions depending on the sensor trajectory and velocity.

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Retrieving time-dependent Green’s functions in optics with low-coherence interferometry

Cited by 8 publications

References 5 publications

Smart optical coherence tomography for ultra-deep imaging through highly scattering media

Smart optical coherence tomography for ultra-deep imaging through highly scattering media

Distortion matrix concept for deep optical imaging in scattering media

Ambient noise correlation-based imaging with moving sensors

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