Manipulating the transmission matrix of scattering media for nonlinear imaging beyond the memory effect

Hofer, Matthias; Brasselet, Sophie

doi:10.1364/ol.44.002137

Cited by 21 publications

(11 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2b. Nevertheless, lateral effects along the ( , ) transverse dimensions are non-negligible only away from the propagation axis, as previously observed in nonlinear refocus-scanning imaging [23].…”

Section: D Speckle Spectral Correlationssupporting

confidence: 66%

Focusing large spectral bandwidths through scattering media

Vesga¹,

Hofer²,

Balla³

et al. 2019

Opt. Express

Self Cite

View full text Add to dashboard Cite

Wavefront shaping is a powerful method to refocus light through a scattering medium. Its application to large spectral bandwidths or multiple wavelengths refocusing for nonlinear bio-imaging in-depth is however limited by spectral decorrelations. In this work, we demonstrate ways to access a large spectral memory of a refocus in thin scattering media and thick forward-scattering biological tissues. First, we show that the accessible spectral bandwidth through a scattering medium involves an axial spatio-spectral coupling, which can be minimized when working in a confocal geometry. Second, we show that this bandwidth can be further enlarged when working in a broadband excitation regime. These results open important prospects for multispectral nonlinear imaging through scattering media.

show abstract

Section: D Speckle Spectral Correlationssupporting

confidence: 66%

Focusing large spectral bandwidths through scattering media

Vesga¹,

Hofer²,

Balla³

et al. 2019

Opt. Express

Self Cite

View full text Add to dashboard Cite

show abstract

“…4(a) shows measured intensity maps for both ω 𝑝 and ω 𝑠 , as deduced from scanning a refocus in the image plane using a 200 nm-step (2 camera pixels in the image plane), through a 300 m thick spinal cord tissue slice. For each TM strategy described above, correction for the heterogeneity of the reference speckles was ensured using a complementary speckle compensation method described in reference [24]. Fields of views of about 40x40 m 2 are obtained, which surpasses the angular memory effect of the scattering medium [24] since the method is not based on spatial memory limitations.…”

Section: Resultsmentioning

confidence: 99%

“…For each TM strategy described above, correction for the heterogeneity of the reference speckles was ensured using a complementary speckle compensation method described in reference [24]. Fields of views of about 40x40 m 2 are obtained, which surpasses the angular memory effect of the scattering medium [24] since the method is not based on spatial memory limitations. The Homogeneity of the obtained image is best for TMinterm and slightly less performant for TMcoh, which is most probably due to the fact that a single correction for the speckle heterogeneities is performed for both wavelengths in this case.…”

Section: Resultsmentioning

confidence: 99%

Coherent Anti-Stokes Raman Scattering Through Thick Biological Tissues by Single-Wavefront Shaping

et al. 2020

Self Cite

View full text Add to dashboard Cite

Coherent Anti Stokes Raman Scattering (CARS) offers many advantages for nonlinear bio-imaging, thanks to its sub-cellular spatial resolution and unique chemical specificity. Its working principle requires two incident pulsed laser beams with distinct frequencies to be focused in space and time, which focus quality however rapidly deteriorates when propagating at large depths in biological tissues. The depth limits of CARS and the capability of wavefront correction to overcome these limits are currently unknown. In this work we exploit the spectral correlation properties of the transmission matrix of a scattering medium in a pulsed regime, to recover coherent focusing for two distant incident CARS wavelengths which propagation is initially uncorrelated. Using wavefront shaping with a single spatial light modulator, we recover CARS generation through thick mice spinal cord tissues where initially no signal is measurable due to scattering, and demonstrate point scanning over large field of views of tens of micrometers.

show abstract

“…This could be improved using spiral phases, as in Ref. [ 11 ], to increase the performance. Note that in the reflection geometry one cannot use an external reference.…”

Section: Discussionmentioning

confidence: 99%

“…There are two options to implement the reference field: through an external reference arm or through an internal reference using part of the SLM active area. While the former takes advantage of all the degrees of freedom of the SLM and generates a uniform reference, the latter is more stable and provides only a speckled reference [ 11 ]. The transmission matrix can also be retrieved without a reference arm, using phase retrieval algorithms based on several calibrations [ 12 ].…”

mentioning

confidence: 99%

Measuring the transmission matrix of a scattering medium using epi-fluorescence light

Premillieu

Piestun

2020

Optics Communications

View full text Add to dashboard Cite

There are several methods to focus light behind a scattering medium, but very few use fluorescence light as feedback or can be used without access to the distal side of the scatterer. Among all the wave-front shaping techniques, retrieving the transmission matrix of a scattering material is the only one that allows for focusing on multiple spots after a single set of measurements. Here we propose a method to retrieve the transmission matrix of a scatterer using fluorescence light as feedback without access to the distal side. The advantage of this method is that it allows focusing on the whole field of view after a single matrix measurement without affecting the sample, making it suitable for reflection epi-illumination geometry microscopy.Introduction. Fluorescence microscopy is widely used for a diversity of samples due to its high contrast, capability of targeting specific structures, and minimal toxicity, which enable dynamic, structural, and molecular interaction studies. However, when it comes to thick or highly scattering samples, the fluorescent signal is degraded. Confocal and multiphoton microscopy give good resolution but depend on ballistic light to focus through the scattering layers [ 1 , 2 ]. When only a speckle pattern reaches the target, wavefront shaping offers a promising opportunity. Several methods have been developed to create a focus behind a turbid layer using the output speckle field as feedback [ 3 ] in an iterative process. Alternatively, the transmission matrix (TM) approach characterizes the medium with a set of input-output measurements that can be used to generate spots over a wide field of view [ 4 ]. In particular, scattered light fluorescence microscopy has shown subwavelength imaging resolution [ 5 ]. The method uses the transmitted speckle field as feedback to create a focus and by scanning it, within the so called memory effect range [ 6 ], images small structures behind highly scattering materials [ 5 , 7 ]. By adding a curvature on the optimized phase mask, scanning within the memory effect range in three dimensions has been demonstrated as well [ 8 ]. Both transmission and reflection geometry have been studied [ 3 , 5 , 7 , 8 ], paving the way to imaging behind or inside turbid media. Another interesting approach combines the advantages of structured illumination microscopy and wavefront shaping to generate a light-sheet behind a turbid medium, enhancing the signal of fluorescent beads by a factor of ~8 [ 9 ]. Most demonstrations of these wavefront shaping methods have provided very good resolution behind a scattering medium, but

show abstract

Manipulating the transmission matrix of scattering media for nonlinear imaging beyond the memory effect

Cited by 21 publications

References 22 publications

Focusing large spectral bandwidths through scattering media

Focusing large spectral bandwidths through scattering media

Coherent Anti-Stokes Raman Scattering Through Thick Biological Tissues by Single-Wavefront Shaping

Measuring the transmission matrix of a scattering medium using epi-fluorescence light

Contact Info

Product

Resources

About