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Created by sebastien.popoff on 14/12/2020
Time reversed optical waves by arbitrary vector spatiotemporal field generation
[M. Mounaix et al., Nat. Commun., 11 (2020)] Time-reversal allows precisely tailoring the spatio-temporal field and was originally demonstrated in acoustics. Time-reversal requires to temporally modulate the optical field independently over a large number of pixels, which is challenging in optical experiments. In the present paper, the authors developed a system allowing the modulation of the optical field spectrally and spatially over a 2d array. Harnessing this new tool, they perform a time-reversal experiment to focus and shape the optical field temporally and spatially through a multimode fiber. |
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Created by admin on 15/09/2020
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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Created by sebastien.popoff on 01/09/2020
Spatio-temporal shaping of light through a scattering medium
[A. Boniface et al., arxiv, 2007.09050 (2020)] Controlling the spatial and temporal properties of a short pulse is already difficult in free space, and require a well-calibrated and specific setup. When the pulse propagates through a scattering medium, its temporal and spatial properties are randomized, leading to a spatio-temporal speckle. However, the effect of the medium can be described by means of the multi-spectral transmission matrix. In this paper, A. Boniface and his colleagues show that by measuring previously this matrix, and by only controlling the spatial input field using a spatial light modulator, they can modulate at will the spatio-temporal properties of the point spread function of a pulse traveling through a complex medium. |
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Created by sebastien.popoff on 18/08/2020
Taking advantage of imperfections to focus light in photonic crystals inside the stop gap |
