@article{21747,
  abstract     = {Entanglement does not always require one particle per party. It was predicted some 30 years ago that a single photon traversing a beam splitter could violate a Bell inequality. Although initially debated, single-photon nonlocality was eventually demonstrated via homodyne measurements. Here, we present an alternate realization that avoids the complexity of homodyne measurements and potential loopholes in their implementation. We violate a Bell inequality by performing joint measurements on two copies of the same single-photon entangled state, where one photon acts as a phase reference for the other, making it self-referential. We observe CHSH parameters of 2.71 = 0.09 and 2.23 = 0.07, depending on the joint measurements implemented. This offers a perspective on single-photon nonlocality and a more accessible experimental route, potentially applicable to general mode-entangled states in diverse platforms.},
  author       = {Kun, Daniel and Strömberg, Karl T and Dakić, Borivoje and Walther, Philip and Rozema, Lee A.},
  issn         = {2334-2536},
  journal      = {Optica},
  number       = {4},
  pages        = {745--751},
  publisher    = {Optica Publishing Group},
  title        = {{Testing single-photon entanglement using self-referential measurements}},
  doi          = {10.1364/OPTICA.586172},
  volume       = {13},
  year         = {2026},
}

@article{21641,
  abstract     = {Spectral filters are widely used in sensing and communicating with light, such as for separating wavelength channels in communications or sensing the specific spectra of some object or material of interest. The filter function is, however, often fixed, and precise filtering can require precise manufacturing. We propose an approach to integrated optical spectral filtering that allows arbitrary programmability, can compensate automatically for imperfections in filter fabrication, allows multiple simultaneous and separately programmable filter functions on the same input, and can configure itself automatically to the problem of interest, for example, to filter or reject multiple arbitrarily chosen frequencies. The approach exploits splitting the input light into an array of multiple waveguides of different lengths that then feed a programmable interferometer array that can also self-configure. It can give a spectral response similar to arrayed waveguide gratings but offers many other filtering functions, as well as supporting other structures based on non-redundant arrays for precise spectral filtering. Simultaneous filtering also allows an automatic measurement of the temporal coherency matrix and physical separation into the Karhunen–Loève expansion of temporally partially coherent light fields. With this approach, a wide range of spectral operations can be controllably, automatically, and precisely performed by an integrated photonic device with simple programmability.},
  author       = {Miller, David A. B. and Roques-Carmes, Charles and Valdez, Carson G. and Kroo, Anne R. and Vlk, Marek and Fan, Shanhui and Solgaard, Olav},
  issn         = {2334-2536},
  journal      = {Optica},
  number       = {9},
  pages        = {1417--1426},
  publisher    = {Optica Publishing Group},
  title        = {{Universal programmable and self-configuring optical filter}},
  doi          = {10.1364/optica.557630},
  volume       = {12},
  year         = {2025},
}

@article{21640,
  abstract     = {Conventional computing architectures have no known efficient algorithms for combinatorial optimization tasks such
as the Ising problem, which requires finding the ground state spin configuration of an arbitrary Ising graph. Physical
Ising machines have recently been developed as an alternative to conventional exact and heuristic solvers; however,
these machines typically suffer from decreased ground state convergence probability or universality for high edge-
density graphs or arbitrary graph weights, respectively. We experimentally demonstrate a proof-of-principle integrated
nanophotonic recurrent Ising sampler (INPRIS), using a hybrid scheme combining electronics and silicon-on-insulator
photonics, that is capable of converging to the ground state of various four-spin graphs with high probability. The
INPRIS results indicate that noise may be used as a resource to speed up the ground state search and to explore larger
regions of the phase space, thus allowing one to probe noise-dependent physical observables. Since the recurrent pho-
tonic transformation that our machine imparts is a fixed function of the graph problem and therefore compatible with
optoelectronic architectures that support GHz clock rates (such as passive or non-volatile photonic circuits that do not
require reprogramming at each iteration), this work suggests the potential for future systems that could achieve orders-
of-magnitude speedups in exploring the solution space of combinatorially hard problems. },
  author       = {Prabhu, Mihika and Roques-Carmes, Charles and Shen, Yichen and Harris, Nicholas and Jing, Li and Carolan, Jacques and Hamerly, Ryan and Baehr-Jones, Tom and Hochberg, Michael and Čeperić, Vladimir and Joannopoulos, John D. and Englund, Dirk R. and Soljačić, Marin},
  issn         = {2334-2536},
  journal      = {Optica},
  number       = {5},
  pages        = {551--558},
  publisher    = {Optica Publishing Group},
  title        = {{Accelerating recurrent Ising machines in photonic integrated circuits}},
  doi          = {10.1364/optica.386613},
  volume       = {7},
  year         = {2020},
}