Light fields in complex media: Mesoscopic scattering meets wave control

Rotter, Stefan; Gigan, Sylvain

doi:10.1103/revmodphys.89.015005

Cited by 535 publications

(433 citation statements)

References 506 publications

(798 reference statements)

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“…Despite the complex structure of speckle patterns, each speckle grain has a deterministic relation to the input fields [1]. Over the last decade, wavefront shaping has turned to be an efficient tool to control monochromatic light through highly scattering systems [2], notably by exploiting the transmission matrix [3].…”

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confidence: 99%

Temporal recompression through a scattering medium via a broadband transmission matrix

Mounaix¹,

Aguiar²,

Gigan³

2017

Optica

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The transmission matrix is a unique tool to control light through a scattering medium. A monochromatic transmission matrix does not allow temporal control of broadband light. Conversely, measuring multiple transmission matrices with spectral resolution allows fine temporal control when a pulse is temporally broadened upon multiple scattering, but requires very long measurement time. Here, we show that a single linear operator, measured for a broadband pulse with a co-propagating reference, naturally allows for spatial focusing, and interestingly generates a two-fold temporal recompression at the focus, compared with the natural temporal broadening. This is particularly relevant for non-linear imaging techniques in biological tissues.When monochromatic coherent light propagates in a medium with high refractive index inhomogeneities, it quickly develops into a speckle. Despite the complex structure of speckle patterns, each speckle grain has a deterministic relation to the input fields [1]. Over the last decade, wavefront shaping has turned to be an efficient tool to control monochromatic light through highly scattering systems [2], notably by exploiting the transmission matrix [3].Under illumination with a source of large bandwidth, each spectral component can generate a different speckle pattern [4]. Therefore one needs to adjust these additional spectral/temporal degrees of freedom to temporally control the output pulse [5]. This can be achieved using methods such as nonlinear optical processes [6,7], time-gating [8,9], and frequency-resolved measurements [10,11]. However, these methods underly either low signal-to-noise measurements (non-linear processes), or stability issues as they require lengthy acquisition procedures [12] and the need of external reference.An alternative approach is to use self-referencing signals, at the expense of lacking control on spectral degrees of freedom. Recently, "broadband wavefront shaping" experiments reported outcomes disparate from what is expected from monochromatic wavefront shaping, such as a decrease in the independent spectral degrees of freedom [13,14], and recovery of pure polarization states [15]. Notably, these results could have an impact on biomedical imaging [16]. Nonetheless, the exact temporal properties of the obtained output pulse via broadband wavefront shaping remain elusive. In this letter, we report the first characterization of the so-called broadband transmission matrix of a scattering medium. We exploit it for focusing purposes, and we analyze and interpret its temporal behavior. Unexpectedly, the characterized average pulse length is shorter than the pulse propagating without shaping. Figure 1a illustrates and summarizes propagation of broadband light (ultrashort pulse of duration δt, spectral width ∆λ) through an optically thick scattering medium. Transmitted light results in a speckle intensity pattern with low contrast C 0 < 1. This low contrast results from the incoherent summation of various uncorrelated speckles corresponding to different spect...

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confidence: 99%

Temporal recompression through a scattering medium via a broadband transmission matrix

Mounaix¹,

Aguiar²,

Gigan³

2017

Optica

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“…II, wavefront shaping techniques for optical focusing at depths inside scattering media typically include two categories. These are pre-compensated wavefront shaping techniques 8,19,[58][59][60][61][62][63] to counteract the phase/intensity distortions induced by multiple scatterings and time-reversed wavefront shaping techniques 24,[64][65][66][67][68][69] to phase-conjugate scattered light back to the guidestar inside the scattering medium. Although the goals are identical, these two categories differ in both principle and implementation.…”

Section: Guidedstar-assisted Wavefront Shaping-based Optical Focmentioning

confidence: 99%

Perspective: Wavefront shaping techniques for controlling multiple light scattering in biological tissues: Toward in vivo applications

Park

Lee

et al. 2018

APL Photonics

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Multiple light scattering has been regarded as a barrier in imaging through complex media such as biological tissues. Owing to recent advances in wavefront shaping techniques, optical imaging through intact biological tissues without invasive procedures can now be used for direct experimental studies, presenting promising application opportunities in in vivo imaging and diagnosis. Although most of the recent proof of principle breakthroughs have been achieved in the laboratory setting with specialties in physics and engineering, we anticipate that these technologies can be translated to biological laboratories and clinical settings, which will revolutionize how we diagnose and treat a disease. To provide insight into the physical principle that enables the control of multiple light scattering in biological tissues and how recently developed techniques can improve bioimaging through thick tissues, we summarize recent progress on wavefront shaping techniques for controlling multiple light scattering in biological tissues.

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“…Over the years, however, the realization has arisen that spatial inhomogeneities that scatter light have advantageous properties and allow applications that are otherwise impossible, for instance, an optical diffuser or a high-numerical aperture objective [2][3][4]. While both the know-how of and the control over optics that strongly scatters light has greatly advanced [5][6][7][8][9][10], the state-of-the-art is much less developed regarding optical systems that also strongly absorb light (or even re-emit light of a different color), even though important application fields occur in this regime, for instance solid-state lighting [11][12][13], biomedical optics [14][15][16][17][18][19], or powder technology [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Analytical modeling of light transport in scattering materials with strong absorption

Meretska¹,

Uppu²,

Vissenberg³

et al. 2017

Opt. Express

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Abstract:We have investigated the transport of light through slabs that both scatter and strongly absorb, a situation that occurs in diverse application fields ranging from biomedical optics, powder technology, to solid-state lighting. In particular, we study the transport of light in the visible wavelength range between 420 and 700 nm through silicone plates filled with YAG:Ce 3+ phosphor particles, that even re-emit absorbed light at different wavelengths. We measure the total transmission, the total reflection, and the ballistic transmission of light through these plates. We obtain average single particle properties namely the scattering cross-section σ s , the absorption cross-section σ a , and the anisotropy factor µ using an analytical approach, namely the P3 approximation to the radiative transfer equation. We verify the extracted transport parameters using Monte-Carlo simulations of the light transport. Our approach fully describes the light propagation in phosphor diffuser plates that are used in white LEDs and that reveal a strong absorption (L/l a > 1) up to L/l a = 4, where L is the slab thickness, l a is the absorption mean free path. In contrast, the widely used diffusion theory fails to describe this parameter range. Our approach is a suitable analytical tool for industry, since it provides a fast yet accurate determination of key transport parameters, and since it introduces predictive power into the design process of white light emitting diodes. 8190-8204 (2014). 30. To be sure, in a scattering system the degree of scattering is given by L/ s rather than L/ t r . Since in the vast majority of scattering systems the transport mean free paths exceeds the scattering mean free path ( t r ≥ s ) due to predominantly forward scattering [34], we consider our characterization to be on the safe side. 31. S. Chandrasekhar, Radiative transfer (Dover, New York NY, 1960). 32. M. Kaveh, Analogies in optics and micro electronics (Springer, Netherlands, 1991) 33.

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Light fields in complex media: Mesoscopic scattering meets wave control

Cited by 535 publications

References 506 publications

Temporal recompression through a scattering medium via a broadband transmission matrix

Temporal recompression through a scattering medium via a broadband transmission matrix

Perspective: Wavefront shaping techniques for controlling multiple light scattering in biological tissues: Toward in vivo applications

Analytical modeling of light transport in scattering materials with strong absorption

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