Compact and programmable large-scale optical processor in free space

Maria Gorizia Ammendola; Nazanin Dehghan; Lukas Scarfe; Alessio D’Errico; Francesco Di Colandrea; Ebrahim Karimi; Filippo Cardano

doi:10.1038/s41377-026-02236-2

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Compact and programmable large-scale optical processor in free space

Original Articles

- Compact and programmable large-scale optical processor in free space
- Light: Science & Applications Vol. 15, Issue 6, Pages: 2009-2022(2026)
- Affiliations：
  
  1.Scuola Superiore Meridionale, Via Mezzocannone, 4, 80138 Napoli, Italy
  2.Nexus for Quantum Technologies, University of Ottawa, K1N 5N6, Ottawa, ON, Canada
  3.Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico Ⅱ, Complesso Universitario di Monte Sant’Angelo, Via Cintia, 80126 Napoli, Italy
  4.National Research Council of Canada, 100 Sussex Drive, Ottawa, ON K1A 0R6, Canada
  5.Institute for Quantum Studies, Chapman University, Orange, CA 92866, USA
- Author bio：
  
  Francesco Di Colandrea (francesco.dicolandrea@unina.it)
  Filippo Cardano (filippo.cardano2@unina.it)
- Funds：
- DOI：10.1038/s41377-026-02236-2
  CLC：
- Received：26 September 2025，
  
  Revised：2026-02-06，
  
  Accepted：09 February 2026，
  
  Online First：19 March 2026，
  
  Published：30 June 2026
- Accepted：
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Ammendola, M. G. et al. Compact and programmable large-scale optical processor in free space. Light: Science & Applications, 15, 2009-2022 (2026).
DOI：

Ammendola, M. G. et al. Compact and programmable large-scale optical processor in free space. Light: Science & Applications, 15, 2009-2022 (2026). DOI： 10.1038/s41377-026-02236-2.

摘要

Abstract

Photonic circuits are central to classical and quantum information processing. While integrated technologies dominate

free-space architectures are emerging as attractive alternatives

offering broad bandwidth and direct manipulation of optical modes without confinement in waveguides. A key challenge for scalability lies in circuit depth

as the number of layers manipulating the optical field typically grows with the system size. Here

we introduce a programmable free-space photonic platform that implements translation-invariant

high-dimensional unitary transformations using only three layers. Information is encoded in structured light modes defined by circular polarization and quantized transverse momenta

and processed with spatial light modulators interleaved with half-wave plates. We implement unitaries that are equivalent to quantum walks over up to 30 time steps

in one- and two-dimensional lattices

distributing a single input mode across more than 7

000 outputs

where conventional approaches would require tens or hundreds of layers. The platform supports diverse quantum walk dynamics

including disorder

synthetic gauge fields

and topological effects

previously explored only in separate experiments. Using coincidence detection with a time-tagging camera

we show compatibility with quantum optics protocols and provide examples of quantum walks of heralded single photons. These results contribute to establishing free-space optical processors as promising resources for high-dimensional quantum simulation and scalable optical information processing.

关键词

Keywords

references

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