Created by sebastien.popoff on 04/07/2020


Endoscopy combining photoacoustic and fluorescence imaging with a small footprint


[S. Mezil et al., arxiv, 2006.10856 (2020)]

Achieving optical-resolution photoacoustic imaging can currently only be obtained using endoscopy. It usually implies a quite bulky endoscope and/or a low signal-to-noise detection. In this paper, the authors present a technique that combines wavefront shaping through a multimode fiber, to scan the focus spot, with a single-mode fiber-based ultrasound sensor to achieve a high signal-to-noise with a small footprint (250 by 125 microns).

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Created by sebastien.popoff on 12/06/2020

Talks Wavefront shaping

Time reversed optical waves by arbitrary vector spatiotemporal field generation

Mickael Mounaix, Nicolas K. Fontaine, David T. Neilson, Roland Ryf, Haoshuo Chen, Juan Carlos Alvarado-Zacarias and Joel Carpenter

This video published on J. Carpenter Youtube Channel explained the details of the experiment of this paper [Mounaix et al., arxiv, 1909.07003, (2019)]. The authors use spatial and spectral shaping with a spatial light modulator to achieve spatio-temporal focusing of light by time-reversal through a multimode fiber.

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Created by sebastien.popoff on 24/10/2019


All-fiber wavefront shaping by transmission matrix engineering

[S. Resisi et al., APL Photonics, 5 (2020)]

In the past 10 years, many applications were successfully demonstrated for wavefront shaping in multimode fibers, from endoscopic to telecommunications through optical tweezers. However, these techniques require to modulate the incident field using free space modulators. In the present paper, S. Resisi and co-authors introduce a new approach that relies on modulating the transmission matrix itself by applying changes that modify its boundary conditions. Using an all-fiber apparatus, focusing light at the distal end of the fiber and conversion between fiber modes is demonstrated. Since in this approach the number of degrees of control can be larger than the number of fiber modes, it allows simultaneous control over multiple inputs and multiple wavelengths.

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Created by sebastien.popoff on 26/05/2019

Tutorials Multimode fibers

Compare Different Methods of Modes Estimation of Bent Multimode Fibers with pyMMF

In a previous tutorial, I explained how to calculate the modes of a bent multimode fibers. I introduced two methods, following the approach published in [M. Plöschner, T. Tyc, and T. Čižmár, Nat. Photon. (2015)]. In this short tutorial, I show how to use pyMMF to simulate bent fibers and compare the two different methods. A Jupyter notebook can be found on my Github account: compare_bending_methods.ipynb.

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