Volume holograms with linear diffraction efficiency relation by (3+1)D printing

We demonstrate the fabrication of volume holograms using 2-photon polymerization with dynamic control of light exposure. We refer to our method as (3+1)D printing. Volume holograms that are recorded by interfering reference and signal beams have a diffraction efficiency relation that is inversely proportional with the square of the number of superimposed holograms. By using (3+1)D printing for fabrication, the refractive index of each voxel is created independently and thus by, digitally filtering the undesired interference terms, the diffraction efficiency is now inversely proportional to the number of multiplexed gratings. We experimentally demonstrated this linear dependence by recording M=50 volume gratings. To the best of our knowledge, this is the first experimental demonstration of distributed volume holograms that overcome the 1/M^2 limit

Visualization 1: Two-photon imaging through a multimode fiber

Optical sectioning Originally published in Optics Express on 14 December 2015 (oe-23-25-32158

3423795.pdf

Supplementary measurement

Multicasting Optical Reconfigurable Switch

Artificial Intelligence (AI) demands large data flows within datacenters, heavily relying on multicasting data transfers. As AI models scale, the requirement for high-bandwidth and low-latency networking compounds. The common use of electrical packet switching faces limitations due to its optical-electrical-optical conversion bottleneck. Optical switches, while bandwidth-agnostic and low-latency, suffer from having only unicast or non-scalable multicasting capability. This paper introduces an optical switching technique addressing the scalable multicasting challenge. Our approach enables arbitrarily programmable simultaneous unicast and multicast connectivity, eliminating the need for optical splitters that hinder scalability due to optical power loss. We use phase modulation in multiple planes, tailored to implement any multicast connectivity map. Using phase modulation enables wavelength selectivity on top of spatial selectivity, resulting in an optical switch that implements space-wavelength routing. We conducted simulations and experiments to validate our approach. Our results affirm the concept's feasibility and effectiveness, as a multicasting switch

Media 1: Focusing and scanning light through a multimode optical fiber using digital phase conjugation

Originally published in Optics Express on 07 May 2012 (oe-20-10-10583

La Lanterne : journal politique quotidien

15 décembre 18821882/12/15 (N2064,A6)

Nonlinear Processing with Linear Optics

Deep neural networks have achieved remarkable breakthroughs by leveraging multiple layers of data processing to extract hidden representations, albeit at the cost of large electronic computing power. To enhance energy efficiency and speed, the optical implementation of neural networks aims to harness the advantages of optical bandwidth and the energy efficiency of optical interconnections. In the absence of low-power optical nonlinearities, the challenge in the implementation of multilayer optical networks lies in realizing multiple optical layers without resorting to electronic components. In this study, we present a novel framework that uses multiple scattering that is capable of synthesizing programmable linear and nonlinear transformations concurrently at low optical power by leveraging the nonlinear relationship between the scattering potential, represented by data, and the scattered field. Theoretical and experimental investigations show that repeating the data by multiple scattering enables non-linear optical computing at low power continuous wave light

Media 1: Resolution enhancement in nonlinear scanning microscopy through post-detection digital computation

Originally published in Optica on 20 December 2014 (optica-1-6-455

Media 1: Dynamic bending compensation while focusing through a multimode fiber

Originally published in Optics Express on 23 September 2013 (oe-21-19-22504

Visualization 1: Digital confocal microscopy through a multimode fiber

Dynamic projection of light patterns at the output of a multimode fiber (‘La Linea’, 1971, Osvaldo Cavandoli). Originally published in Optics Express on 07 September 2015 (oe-23-18-23845