Created by sebastien.popoff on 06/10/2020

Highlights

Model-based wavefront shaping microscopy

[A. Thendiyammal et al.,  Opt. Lett., 45 (2020)]

Wavefront shaping offers the possibility to increasing microscopic imaging depth. By learning how to focus deep inside a (not too) scattering medium, we also learn how to compensate for scattering effects around this area, allowing us to retrieve an image of this area. Typically, finding the wavefront that focuses light at a given target is done using a feedback optimization procedure, or by measuring the response of the system. In this paper, the authors propose another approach. They first create a model of the system thanks to some calibration measurements. The model is then used for finding the optical input wavefront that would be utilized for imaging at different depths. They experimentally demonstrate the advantage of this technique for two-photon fluorescent imaging through a low scattering medium.

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Created by sebastien.popoff on 29/09/2020

Highlights Tutorials Spatial Light Modulators

Easy characterization of SLMs' phase deformation

[D. Marco et al., Opt. Lett., 45 (2020)]

Technical papers are important for the scientific community, it helps in particular to reproduce experimental setups. They are unfortunately not valued enough by scientific journals. I want today to highlight such a paper. Liquid crystals phase modulators - and indeed any kind of spatial light modulator (SLM) - are not free of imperfections. One effect that appears is a phase distortion of the reflected field due to spatial non-uniformities that occur during the fabrications. In practice, if you illuminate an SLM with a plane wave and you display a uniform mask, one does not end up with a plane wave, but an aberrated wavefront. In the present paper, the authors use a quite easy to implement technique to retrieve the phase distortion introduced by the SLM.

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Created by sebastien.popoff on 16/09/2020

Job offers

Postdoctoral position: Matrix approach for resonant multiple scattering of light (theory)

Langevin Institute, Paris

We propose a 2 years postdoctoral position in the Waves Theory and Mesoscopic Physics group of the Langevin Institute under the supervision of Arthur Goetschy. The goal of the project is to provide a theory for the scattering matrix of strongly scattering media made of resonant units for wavefront shaping applications. Applicants should have a Ph.D. in wave physics with a solid background on wave propagation in complex systems.
Contact: arthur.goetschy@espci.psl.eu

More information here:
 

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Created by admin on 15/09/2020

Highlights

Real-time shaping of entangled photons by classical control and feedback

[O. Lib, G. Hasson and Y. Bromberg, Sci. Adv. 6 (2020)]

Wavefront shaping offers the possibility to compensate for the effect of propagation through heterogeneous media. However, when using a single or a few photons, the feedback signal is typically too weak to allow real-time wavefront shaping applications, which limits applications for quantum communications using entangled photons. In this paper from the team of Yaron Bromberg at the Hebrew University of Jerusalem, the authors overcome this challenge by using as feedback the classical signal of the pump that follows the same path as the entangled photon. It allows adapting in real-time the pump wavefront to compensate for the aberrations/scattering introduced by a heterogeneous dynamic sample.

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