Measurements on the optical transmission matrices of strongly scattering nanowire layers

Akbulut, D.; Strudley, Tom; Bertolotti, Jacopo; Zehender, Tilman; Bakkers, Erik P. A. M.; Lagendijk, Ad; Vos, Willem L.; Muskens, Otto L.; Mosk, Allard

doi:10.1109/cleoe-iqec.2013.6801893

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…While this method allows to measure every input angle directly, thanks to the movable mirrors, it does not permit to generate a given arbitrary wavefront directly. On the detection side, in order to record the amplitude hologram of the output speckle in a single image rather than in a sequence, off-axis holography was implemented (Akbulut et al, 2013;Kim et al, 2012). Using a set of polarization beamsplitters and polarization optics, it is also possible to control or to detect both polarizations at the same time, thus access-re th we as re se ed igsis sis nseal rix ce ess tly f a ric a nt mission matrix of our system, which is done in approximately 3 min (and requires 4N measurements), comparable to the time needed to perform an iterative focusing as FIG.…”

Section: Accessing the Monochromatic Transmission Matrix Of An Opaquementioning

confidence: 99%

Light fields in complex media: Mesoscopic scattering meets wave control

2017

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The newly emerging field of wave front shaping in complex media has recently seen enormous progress. The driving force behind these advances has been the experimental accessibility of the information stored in the scattering matrix of a disordered medium, which can nowadays routinely be exploited to focus light as well as to image or to transmit information even across highly turbid scattering samples. We will provide an overview of these new techniques, of their experimental implementations as well as of the underlying theoretical concepts following from mesoscopic scattering theory. In particular, we will highlight the intimate connections between quantum transport phenomena and the scattering of light fields in disordered media, which can both be described by the same theoretical concepts. We also put particular emphasis on how the above topics relate to application-oriented research fields such as optical imaging, sensing and communication.

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Section: Accessing the Monochromatic Transmission Matrix Of An Opaquementioning

confidence: 99%

Light fields in complex media: Mesoscopic scattering meets wave control

2017

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“…1a). This reference beam can either be co-propagating in the medium [7,21], or use an external reference arm [22,8]. The phase and amplitude of the measured field can then be extracted by simple linear combinations of interference patterns with a phaseshifted or off-axis reference.…”

Section: Introductionmentioning

confidence: 99%

Reference-less measurement of the transmission matrix of a highly scattering material using a DMD and phase retrieval techniques

Drémeau¹,

Liutkus²,

Martina³

et al. 2015

Opt. Express

218

140

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This paper investigates experimental means of measuring the transmission matrix (TM) of a highly scattering medium, with the simplest optical setup. Spatial light modulation is performed by a digital micromirror device (DMD), allowing high rates and high pixel counts but only binary amplitude modulation. On the sensor side, without a reference beam, the CCD camera provides only intensity measurements. Within this framework, this paper shows that the TM can still be retrieved, through signal processing techniques of phase retrieval. This is experimentally validated on three criteria : quality of prediction, distribution of singular values, and quality of focusing.

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“…3 However, the interference between numerous modes, along with polarization mixing, distort images into randomized speckle patterns at the fiber output. To reconstruct original images, various approaches have been explored, including transmission matrix formulation[, [4][5][6][7] phase conjugation, 8,9 and deep learning . 10 Deep learning techniques present an attractive solution for image reconstruction problems due to their high reconstruction fidelity, and unlike other methods, they do not require complex phase measurements and a stable reference arm.…”

Section: Introductionmentioning

confidence: 99%

Application of conditional generative adversarial networks toward time-efficient and high-fidelity imaging via multimode fibers

Maqbool,

Talal Hassan,

Cheema

2024

AI and Optical Data Sciences V

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Several modes exist in multimode fibers due to their large core diameter. Due to this property, they can transport images from one point to another. However, due to mode and polarization mixing, they randomize any information at their input to form speckle patterns. Original images from these patterns can be successfully reconstructed using methods like phase conjugation, transmission matrix measurement, and deep learning. Deep learning techniques are attractive as they are less time-consuming and do not require complex phase measurements and setups. Recently, researchers have used attention blocks with U-NET architecture to regenerate images from speckles. In this case, the average structural similarity index measure (SSIM) of reconstructed images is 0.8772. However, the network is complex and has high computation costs. As conditional generative adversarial networks (CGAN) produce better results for image-to-image translation problems, scientists have used them to reconstruct images from speckles with an average SSIM of 0.8686. We have designed a CGAN model that is fast (1 hour training time, 9.4ms inference time), stable (no mode collapse), and produces high-accuracy results. We have created our own data sets by sending 60000(MNIST and Fashion MNIST) images at fiber input using a spatial light modulator while simultaneously recording speckle patterns on camera. The average SSIM achieved in our case is 0.9010 for 5000 unseen MNIST test images, which is greater than the previously reported values. The high-fidelity and fast imaging using our CGAN model offers the potential for developing thin, minimally invasive endoscopes using multimode fibers.

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Measurements on the optical transmission matrices of strongly scattering nanowire layers

Cited by 4 publications

References 9 publications

Light fields in complex media: Mesoscopic scattering meets wave control

Light fields in complex media: Mesoscopic scattering meets wave control

Reference-less measurement of the transmission matrix of a highly scattering material using a DMD and phase retrieval techniques

Application of conditional generative adversarial networks toward time-efficient and high-fidelity imaging via multimode fibers

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