- 8
- April
- 2025
CREF promotes original and high-impact lines of research, based on physical methods, but with a strong interdisciplinary character and in relation to the main problems of the modern knowledge society.
The CREF was born with a dual soul: a research centre and a historical museum. Its aim is to preserve and disseminate the memory of Enrico Fermi and to promote the dissemination and communication of scientific culture.
Higher education and projects for young researchers
Title: Large-scale photonic computing with nonlinear disordered media
Authors: Hao Wang, Jianqi Hu, Andrea Morandi, Alfonso Nardi, Fei Xia, Xuanchen Li, Romolo Savo, Qiang Liu, Rachel Grange & Sylvain Gigan
published in Nature Computational Science (2024) Cite this article
Abstract
Neural networks find widespread use in scientific and technological applications, yet their implementations in conventional computers have encountered bottlenecks due to ever-expanding computational needs. Photonic computing is a promising neuromorphic platform with potential advantages of massive parallelism, ultralow latency and reduced energy consumption but mostly for computing linear operations. Here, we demonstrate a large-scale, high-performance, nonlinear photonic neural system based on a disordered polycrystalline slab of lithium niobate nanocrystals. Mediated by random quasi-phase-matching and multiple scattering, linear and nonlinear optical speckle features are generated as the interplay between the simultaneous linear random scattering and the second-harmonic generation, defining a complex neural network in which the second-order nonlinearity acts as internal nonlinear activation functions. Benchmarked against linear random projection, such nonlinear mapping embedded with rich physical computational operations shows improved performance across a large collection of machine learning tasks in image classification, regression and graph classification. Demonstrating up to 27,648 input and 3,500 nonlinear output nodes, the combination of optical nonlinearity and random scattering serves as a scalable computing engine for diverse applications.
Via Panisperna 89 A – 00184 Roma
PEC: centrofermi@pec.centrofermi.it
CUU: UF5JTW
Phone: +39 06 4550 2901
VAT: 06431991006
CF: 97214300580
Mail: via Panisperna 89a – 00184 Rome
Guest Entrance: Piazza del Viminale 1 – 00184 Rome