@article{21561, abstract = {Enhancing interactions in many-body quantum systems, while protecting them from environmental decoherence, is at the heart of many quantum technologies. Waveguide quantum electrodynamics is a promising platform for achieving this, as it hosts infinite-range interactions and decoherence-free subspaces of quantum emitters. However, as coherent interactions between emitters are typically washed out in the wavelength-spacing regime hosting decoherence-free states, coherent control over the latter becomes limited, and many-body Hamiltonians in this important regime remain out of reach. Here we show that by incorporating emitter arrays with nonlinear waveguides hosting parametric gain, we obtain a unique class of many-body interaction Hamiltonians with coupling strengths that increase with emitter spacing, and persist even for wavelength-spaced arrays. We then propose to use these Hamiltonians to coherently generate decoherence-free states directly from the ground state, using only global squeezing drives, without the need for local addressing of individual emitters. Interestingly, we find that the dynamics approaches a unitary evolution in the limit of weak intrawaveguide squeezing, and we discuss potential experimental realizations of this effect. Our results pave the way towards coherent control protocols in waveguide quantum electrodynamics, with applications including quantum computing, simulation, memory, and nonclassical light generation.}, author = {Karnieli, Aviv and Tziperman, Offek and Roques-Carmes, Charles and Fan, Shanhui}, issn = {2643-1564}, journal = {Physical Review Research}, number = {1}, publisher = {American Physical Society }, title = {{Decoherence-free many-body Hamiltonians in nonlinear waveguide quantum electrodynamics}}, doi = {10.1103/physrevresearch.7.l012014}, volume = {7}, year = {2025}, } @article{21562, abstract = {Many quantum systems exhibit high sensitivity to their initial conditions, where microscopic quantum fluctuations can significantly influence macroscopic observables. Understanding how quantum states may influence the behavior of nonlinear dynamic systems may open new avenues in controlling light-matter interactions. To explore this issue, we analyze the sensitivity of a fundamental quantum optical process – parametric oscillation – to quantum initializations. Focusing on optical parametric oscillators (OPOs), we demonstrate that the quantum statistics of arbitrary initial states are imprinted in the early-stage dynamics and can persist in the steady-state probabilities. We derive the “quantum sensitivity” of parametric oscillators, linking the initial quantum state to the system's steady-state outcomes, highlighting how losses and parametric gain govern the system's quantum sensitivity. Moreover, we show that these findings extend beyond OPOs to a broader class of nonlinear systems, including Josephson junction based superconducting circuits. Our work opens the way to a new class of experiments that can test the sensitivity of macroscopic systems to quantum initial conditions and offers a pathway for controlling systems with quantum degrees of freedom.}, author = {Gu, Alex and Sloan, Jamison and Roques-Carmes, Charles and Choi, Seou and Rosenthal, Eric I. and Horodynski, Michael and Salamin, Yannick and Vučković, Jelena and Soljačić, Marin}, issn = {2643-1564}, journal = {Physical Review Research}, number = {2}, publisher = {American Physical Society}, title = {{Quantum sensitivity of parametric oscillators}}, doi = {10.1103/physrevresearch.7.l022056}, volume = {7}, year = {2025}, } @inproceedings{21566, abstract = {We introduce a new class of self-configuring photonic architectures called variational optical processors (VOPs). These devices tackle the problem of decomposing and measuring multimode light fields, both partially coherent and quantum, without requiring prior knowledge of the modes involved. Classical strategies for modal decomposition—such as Karhunen-Loève expansions [1] for partially coherent beams or Schmidt decompositions [2] for bipartite quantum states—often rely on comprehensive tomography and complex data processing. By contrast, VOPs discover the relevant modes in situ through a simple optimization of detection signals at their outputs (e.g., measured optical power or coincidence counts), eliminating the overhead usually associated with scanning and reconstruction. Prior demonstrations of self-configuring photonic networks have proven the feasibility of such approaches for analyzing and generating multimode coherent optical fields [3].}, author = {Roques-Carmes, Charles and Karnieli, Aviv and Miller, David A.B. and Fan, Shanhui}, booktitle = {2025 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference}, issn = { 2833-1052 }, location = {Munich, Germany}, publisher = {IEEE}, title = {{Variational optical processors}}, doi = {10.1109/cleo/europe-eqec65582.2025.11109871}, year = {2025}, } @inproceedings{21567, abstract = {Scintillation, the emission of light by materials impinged by high-energy particles, is vital for scientific and technological applications - used in most security scanners and medical imaging systems. The incident particles excite energetic electrons that undergo a cascade of interactions forming electron-hole pairs, which recombine to emit light. Due to the complex physics of scintillators, their improvement requires optimizing multiple material properties that are often contradictory: high stopping power, efficient light emission, and optical transparency.}, author = {Regev, Nathan and Shultzman, Avner and Loignon-Houle, Francis and Roques-Carmes, Charles and Kaminer, Ido}, booktitle = {2025 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference}, issn = {2833-1052 }, location = {Munich, Germany}, publisher = {IEEE}, title = {{Neural network inverse design of nanophotonic scintillators}}, doi = {10.1109/cleo/europe-eqec65582.2025.11110329}, year = {2025}, } @inproceedings{21570, abstract = {Nanophotonic scintillators, which feature nanostructures at the scale of their emission wavelength, provide a promising approach to enhancing light yield with a substantially reduced thickness. Here, we demonstrate a six-fold emission enhancement over a wafer scale area of 4 cm x 4 cm and 0.5 mm thickness. This facilitates the development of brighter and thinner X-ray scintillators, which could lead to low-dose and high-resolution X-ray imaging with promising applications in medical imaging and nondestructive inspection.}, author = {Martin-Monier, Louis and Pajovic, Simo and Abebe, Muluneh G. and Chen, Joshua and Vaidya, Sachin and Min, Seokhwan and Choi, Seou and Kooi, Steven E. and Maes, Bjorn and Hu, Juejun and Soljačić, Marin and Roques-Carmes, Charles}, booktitle = {19th International Congress on Artificial Materials for Novel Wave Phenomena}, issn = {2573-2706 }, location = {Amsterdam, Netherlands }, publisher = {IEEE}, title = {{Large-area nanophotonic scintillators for X-ray imaging}}, doi = {10.1109/metamaterials65622.2025.11174194}, year = {2025}, } @inproceedings{21571, abstract = {Recent developments at the intersection of nanophotonics and scintillator materials development have led to the conceptualization and demonstration of so-called “nanophotonic scintillators [1–4].” Nanophotonic scintillators consist of scintillator materials integrated into nanophotonic structures, patterned at the scale of their optical emission wavelength. Nanophotonic scintillators are a promising platform to control and enhance spontaneous light emission in scintillators. Mechanisms of light control and generation enhancement with nanophotonic scintillators include (1) angular light emission control and outcoupling enhancements with surface-patterned scintillators [1, 2]; and (2) enhancement of the rate of spontaneous emission by volumetric patterning, leveraging the Purcell effect [3, 4]. Each of these methods entail the development of dedicated nanofabrication methods to realize wavelength-scale patterns into scintillator materials. In this talk, I will review some recent theoretical and experimental developments in nanophotonic scintillators. I will first present a general theoretical framework to model scintillation in arbitrary nanophotonic structures, which also lends itself to shape optimization of nanophotonic structures for enhanced scintillation. Then, I will review some recent experimental demonstrations in surface-patterned photonic crystal scintillators and multilayer scintillators. Based on this framework and recent theoretical proposals, I will also present other nanophotonic scintillator designs for enhanced spatial resolution and efficiency, as well as software-hardware co-design of nanophotonic scintillators for enhanced x-ray imaging [5, 6].}, author = {Roques-Carmes, Charles}, booktitle = {Nuclear Science Symposium, Medical Imaging Conference and Room Temperature Semiconductor Detector Conference }, issn = {2577-0829 }, location = {Yokohama, Japan}, publisher = {2025 IEEE Nuclear Science Symposium (NSS), Medical Imaging Conference (MIC) and Room Temperature Semiconductor Detector Conference (RTSD)}, title = {{A few recent developments in nanophotonic scintillators}}, doi = {10.1109/nss/mic/rtsd57106.2025.11287777}, year = {2025}, } @article{21572, abstract = {This study focuses on advancing metascintillators to break the 100 ps barrier and approach the 10 ps target. We exploitnanophotonic features, specifically the Purcell effect, to shape and enhance the scintillation properties of the first-generation metascintillator. We demonstrate that a faster emission is achievable along with a more efficient conversionefficiency. This results in a coincidence time resolution improved by a factor of 1.3, crucial for TOF-PET applications.}, author = {Shultzman, A. and Schütz, R. and Kurman, Y. and Lahav, N. and Dosovitskiy, G. and Roques-Carmes, Charles and Bekenstein, Y. and Konstantinou, G. and Latella, R. and Zhang, L. and Loignon-Houle, F. and Gonzalez, A. J. and Benlloch, J. M. and Kaminer, I. and Lecoq, P.}, issn = {2469-7303}, journal = {IEEE Transactions on Radiation and Plasma Medical Sciences}, keywords = {Nanophotonics, Positron emission tomography, scintillators}, number = {2}, pages = {141--147}, publisher = {Institute of Electrical and Electronics Engineers}, title = {{Toward a second generation of metascintillators using the Purcell effect}}, doi = {10.1109/trpms.2024.3471251}, volume = {9}, year = {2025}, } @inproceedings{21576, abstract = {In quantum optics, optical parametric oscillators (OPOs) have long served as testbeds for exploring quantum states and generating randomness. Here, we demonstrate that by applying vacuum-level coherent biasing, OPOs can be engineered as versatile hardware elements for stochastic computing. Specifically, we present a time-multiplexed, biased OPO system that enables discriminative and generative machine learning tasks, such as uncertainty-aware classification and the generation of MNIST digits directly from quantum vacuum noise. Beyond machine learning, we propose the use of biased OPO arrays for implementing fundamental stochastic logic gates and solving combinatorial optimization problems. Finally, we discuss the potential of on-chip OPO systems, which promise substantial improvements in latency and energy efficiency, paving the way for integrated stochastic computing architectures.}, author = {Roques-Carmes, Charles and Salamin, Yannick and Choi, Seou and Horodynski, Michael and Sloan, Jamison and Luo, Di and Soljacic, Marin}, booktitle = {AI and Optical Data Sciences VI}, issn = {0277-786X}, location = {San Francisco, CA, United States}, publisher = {SPIE}, title = {{Stochastic computing with biased optical parametric oscillators}}, doi = {10.1117/12.3037014}, volume = {13375}, year = {2025}, } @inproceedings{21577, abstract = {Nonlinear optics is the workhorse for countless applications in classical and quantum optics, from optical bistability to single photon pair generation. However, the intrinsic weakness of optical nonlinearity has largely limited the efficiency of nonlinear frequency conversion. Here, motivated by recent advances in using non-Hermitian photonics to enable non-reciprocal light transport, we explore how the interplay between non-Hermiticity and optical nonlinearity leads to a fundamentally new regime of nonlinear frequency conversion. We describe how nonreciprocity in coupling between discrete frequency modes can be engineered to yield unidirectional energy flow towards the boundary mode of a frequency comb, closely resembling a non-Hermitian skin effect. Applying this mechanism to an infrared (IR) comb with cascaded second-order nonlinearity, we demonstrate high (>85%) nonlinear conversion efficiency into the “skin” mode and high-power THz generation through enhancement of THz-creating nonlinear processes. We also show how these effects are robust to defects and disorder in the comb and can be harnessed to generate stable limit cycles and comb generation at IR and THz frequencies.}, author = {Pontula, Sahil and Vaidya, Sachin and Roques-Carmes, Charles and Uddin, Shiekh Z. and Soljacic, Marin and Salamin, Yannick}, booktitle = {Nonlinear Frequency Generation and Conversion: Materials and Devices XXIV}, location = {San Francisco, CA, United States}, publisher = {SPIE}, title = {{Non-reciprocal frequency conversion in a multimode nonlinear cavity}}, doi = {10.1117/12.3040830}, volume = {13347}, year = {2025}, } @inproceedings{21578, abstract = {Scintillation describes the conversion of high-energy particles into light in transparent media and finds diverse applications such as high-energy particle detection and industrial and medical imaging. This process operates on multiple timescales, with the final radiative step consisting of spontaneous emission, which can be modeled within the framework of fluctuational electrodynamics. Scintillation can therefore be controlled and enhanced via nanophotonic effects, which has been experimentally demonstrated in recent works. Such designs have thus far obeyed Lorentz reciprocity, meaning there is a direct equivalence between scintillation emission from the design and absorption of a plane wave in the far-field. However, scintillators that do not obey reciprocity have not been explored, even though they represent a novel platform for probing emission which is both nonequilibrium and nonreciprocal in nature. In this work, we propose to harness nonreciprocity to achieve directional control of scintillation emission, granting an additional degree of control over scintillation. Such directionality of light output is important in improving collection efficiencies along off-normal directions towards detectors in certain radiation detection schemes. We present the design of a nonreciprocal scintillator using a one-dimensional magnetophotonic crystal in the Voigt configuration. Our work demonstrates the potential of controlling nonequilibrium emission such as scintillation by breaking reciprocity and expands the space of nanophotonic design for achieving such control.}, author = {Long, Olivia and Pajovic, Simo and Roques-Carmes, Charles and Tsurimaki, Yoichiro and Rivera, Nicholas and Soljacic, Marin and Boriskina, Svetlana and Fan, Shanhui}, booktitle = {Photonic and Phononic Properties of Engineered Nanostructures XV}, location = {San Francisco, CA, United States}, publisher = {SPIE}, title = {{Nonreciprocal scintillation using magneto-optical photonic crystals}}, doi = {10.1117/12.3041590}, volume = {13377}, year = {2025}, } @inproceedings{21579, abstract = {We propose and experimentally demonstrate a method to study intracavity quantum states and their dynamics in an optical parametric oscillator (OPO). By measuring the OPO steady state’s sensitivity to an external bias field, we show how intracavity quantum states can be reconstructed. Our method includes precise control over the pump phase, facilitating arbitrary quadrature reconstruction and enabling complete visualization of cavity states using Husimi Q-function representations. We experimentally demonstrate the quantum tomography of an intracavity squeezed vacuum state generated by an OPO pumped below threshold. Additionally, by controlling the bias time delay and amplitude relative to the pump it allows for the reconstruction of the intracavity state at various times, offering insights into the temporal evolution of the OPO intracavity state. This approach provides a powerful tool for exploring and understanding the intricate behavior of quantum states within optical cavities.}, author = {Salamin, Yannick and Roques-Carmes, Charles and Choi, Seou and Sloan, Jamison and Horodynski, Michael and Luo, Di and Soljačić, Marin}, booktitle = {AI and Optical Data Sciences VI}, location = {San Francisco, CA, United States}, publisher = {SPIE}, title = {{Quantum tomography and intracavity dynamics with a biased optical parametric oscillator}}, doi = {10.1117/12.3043893}, volume = {13375}, year = {2025}, } @inproceedings{21580, abstract = {Free electrons are an emerging new type of quantum probe, with high quantum coherence, sub fsec – sub-nm resolution, high tunability and pristine coherent control. Recent experimental and theoretical advancements showcased the quantum nature of the interaction between a free electron and light and bound-electron qubits, with demonstrations of strong electron-photon coupling and coincidence, and proposals for quantum light generation.}, author = {Karnieli, Aviv and Roques-Carmes, Charles and Yu, Renwen and Fan, Shanhui}, booktitle = {Quantum Sensing, Imaging, and Precision Metrology III}, location = {San Francisco, CA, United States}, publisher = {SPIE}, title = {{Quantum optics with free electrons: From quantum sensing to strong coupling and single-photon nonlinearity}}, doi = {10.1117/12.3053188}, volume = {13392}, year = {2025}, } @inproceedings{21593, abstract = {We show that photonic crystals patterned on tungsten X-ray tube anodes can enhance their thermal emissivity, thus improving heat dissipation. We predict that this approach could facilitate high-power X-ray imaging modalities such as phase-contrast imaging.}, author = {Pajovic, Simo and Roques-Carmes, Charles and Choi, Seou and Kooi, Steven E. and Gupta, Rajiv and Zalis, Michael E. and Celanovic, Ivan and Soljačić, Marin}, booktitle = {Conference on Lasers and Electro-Optics}, location = {Long Beach, CA, United States}, pages = {AA108_5}, publisher = {Optica Publishing Group}, title = {{Nanophotonic thermal management for high-brightness X-ray sources}}, doi = {10.1364/cleo_at.2025.aa108_5}, year = {2025}, } @inproceedings{21594, abstract = {We present an approach for high-resolution scintillation-based imaging by utilizing phase mask metasurfaces, predicting a 10-fold spatial resolution enhancement while maintaining high light yield with thick scintillators.}, author = {Chen, Joshua and Pajovic, Simo and Vaidya, Sachin and Michaels, William and Pontula, Sahil and Choi, Seou and Martin-Monier, Louis and Hu, Juejun and Cogswell, Carol and Roques-Carmes, Charles and Soljačić, Marin}, booktitle = {Conference on Lasers and Electro-Optics}, location = {Long Beach, CA, United States}, publisher = {Optica Publishing Group}, title = {{Phase mask metasurfaces for high-resolution X-ray imaging}}, doi = {10.1364/cleo_at.2025.aa137_2}, year = {2025}, } @inproceedings{21606, abstract = {We demonstrate how vacuum fluctuations can induce switching between two macroscopic steady states in nonlinear driven-dissipative systems. We investigate how switching behavior depends on the system parameters of optical parametric oscillators.}, author = {Huang, Yihao and Choi, Seou and Salamin, Yannick and Sloan, Jamison and Roques-Carmes, Charles and Horodynski, Michael and Soljačić, Marin}, booktitle = {Conference on Lasers and Electro-Optics}, location = {Long Beach, CA, United States}, publisher = {Optica Publishing Group}, title = {{Vacuum-induced switching between macroscopic states}}, doi = {10.1364/cleo_fs.2025.ff100_4}, year = {2025}, } @inproceedings{21607, abstract = {We introduce “variational optical processors,” self-configuring photonic networks that learn modal representations of partially coherent or quantum optical fields through optimization, applicable to diverse classical and quantum optical processing tasks.}, author = {Roques-Carmes, Charles and Karnieli, Aviv and Miller, David A. B. and Fan, Shanhui}, booktitle = {Conference on Lasers and Electro-Optics}, location = {Long Beach, CA, United States}, pages = {FF105_7}, publisher = {Optica Publishing Group}, title = {{Variational optical processors}}, doi = {10.1364/cleo_fs.2025.ff105_7}, year = {2025}, } @inproceedings{21608, abstract = {We design self-configuring optical network architectures for continuous-variable quantum information processing of multimode squeezed vacuum, allowing scalable implementations in real and synthetic dimensions.}, author = {Karnieli, Aviv and Roques-Carmes, Charles and Mor, Paul-Alexis and Lustig, Eran and Sloan, Jamison and Vučković, Jelena and Miller, David A. B. and Fan, Shanhui}, booktitle = {Conference on Lasers and Electro-Optics}, location = {Long Beach, CA, United States}, publisher = {Optica Publishing Group}, title = {{Continuous-variable quantum information processing in real and synthetic dimensions with self-configuring optics}}, doi = {10.1364/cleo_fs.2025.ff105_8}, year = {2025}, } @inproceedings{21609, abstract = {We study the breakdown of the squeezed reservoir assumption commonly employed in enhancing light-matter interaction. We conclude that using an effective squeezed bath on a single mode can provide enhancement, with sufficiently large bandwidth.}, author = {Le, Trung Kien and Lukin, Daniil and Roques-Carmes, Charles and Karnieli, Aviv and Guidry, Melissa A. and Lustig, Eran and Fan, Shanhui and Vučković, Jelena}, booktitle = {Conference on Lasers and Electro-Optics}, location = {Long Beach, CA, United States}, publisher = {Optica Publishing Group}, title = {{Cavity quantum electrodynamics in finite-bandwidth squeezed reservoir}}, doi = {10.1364/cleo_fs.2025.ff109_7}, year = {2025}, } @inproceedings{21610, abstract = {We introduce a framework for studying quantum mechanical interactions between an electron beam and systems with quantized degrees of freedom, such as color centers and electromagnetic fields in cavities. We showcase applications of our framework in quantum metrology and spin control.}, author = {Grzesik, Jakob and Roques-Carmes, Charles and Karnieli, Aviv and Black, Dylan S. and Catanzaro, Dominic and Solgaard, Olav and Fan, Shanhui and Vučković, Jelena}, booktitle = {Conference on Lasers and Electro-Optics}, location = {Long Beach, CA, United States}, pages = {FF113_2}, publisher = {Optica Publishing Group}, title = {{A general framework for interactions between electron beams and quantum optical systems}}, doi = {10.1364/cleo_fs.2025.ff113_2}, year = {2025}, } @inproceedings{21611, abstract = {Scintillation represents a promising platform for exploring emission that is both nonequilibrium and nonreciprocal. In this work, we propose a nonreciprocal scintillator using a one-dimensional magnetophotonic crystal in the Voigt configuration.}, author = {Long, Olivia Y. and Pajovic, Simo and Roques-Carmes, Charles and Tsurimaki, Yoichiro and Rivera, Nicholas and Soljačić, Marin and Boriskina, Svetlana V. and Fan, Shanhui}, booktitle = {Conference on Lasers and Electro-Optics}, location = {Long Beach, CA, United States}, publisher = {Optica Publishing Group}, title = {{Nonreciprocal scintillation using magnetophotonic crystals}}, doi = {10.1364/cleo_fs.2025.ff128_5}, year = {2025}, }