Programmable and nonvolatile computing with composition tuning in thin film lithium niobate

Authors: Abhiram Devata, Axel Magaña Ponce, David Barton

Published: February 10, 2026

Matrix-vector multiplications are fundamental operations in artificial intelligence and high-throughput computations, and are executed repeatedly during training and inference. Their high energy cost in electronic processors motivate scalable photonic computing approaches that reduce the energy required per operation. Thin film lithium niobate (TFLN) is a dominant photonic platform due to its large electro-optic effect. However, it lacks nonvolatile index tuning mechanisms, which promise to pave the way for energy-efficient photonic computing. Here, we explore electrochemical lithiation as a route to nonvolatile matrix-vector multiplications in TFLN. The LiNbO3 phase is stable at room temperature over a 2% Li composition window with an associated composition-dependent refractive index. We computationally demonstrate this as a programmable, low-loss approach to perform matrix-vector multiplications by using composition to control matrix weights. We design Mach-Zehnder interferometers to perform image processing tasks under realistic material loss constraints. We also design microring resonators for iterative weight updates, using gradient descent training to program target matrix operations with matrix-vector multiplication accuracy validated at 1.5% average relative error. These demonstrations show a facile route towards nonvolatile photonic computing in TFLN, addressing a critical requirement for energy-efficient photonic matrix operations at scale.

Lithium niobate quadratic integrated nonlinear photonics: enabling ultra-wide bandwidth and ultrafast photonic engines

Authors: Meng Tian, Guanyu Han, Ziyao Feng, Yu Liu, Yu Wang, Wenjun Deng, Ayed Al Sayem, Qiushi Guo

Published: February 9, 2026

Integrated photonic coherent light sources capable of generating emission with broad spectral coverage and ultrashort pulse durations are critical for both fundamental science and emerging technologies. In this Perspective, we start by discussing emerging quantum and classical photonic applications from the standpoint of operating wavelength and timescale, highlighting the technological gaps that persist in current integrated photonic light sources. Next, we introduce the unique properties of lithium niobate-based integrated quadratic nonlinear photonics, and discuss several promising strategies that exploit this platform to realize wavelength-tunable continuous wave light sources and broadband, ultra-short light pulse generation. We also assessed their advantages and limitations while discussing potential solutions. Finally, we outline future prospects and challenges that need to be addressed, aiming at inspiring continued research and innovation in this rapidly evolving field.

High-brightness fiber-based Sagnac source of entangled photon pairs for multiplexed quantum networks

Authors: Tess Troisi, Yoann Pelet, Romain Dalidet, Gregory Sauder, Olivier Alibart, Sébastien Tanzilli, Anthony Martin

Published: February 9, 2026

A fully fibered source of entangled photon pairs based on a nonlinear Sagnac interferometer is reported. Operating at telecom wavelengths, the source relies exclusively on standard fiber-optic components and periodically poled lithium niobate (PPLN) waveguides, resulting in a compact, robust, and field-deployable architecture. The generation stage supports both polarization and energy-time entanglement without modification, enabling versatile operation depending on the targeted application. Broadband spontaneous parametric down-conversion allows dense wavelength-division multiplexing over the telecom C and L bands. High normalized brightness (10.3 kpairs/s/nm/mW$^2$) is achieved on a standard 100 GHz ITU channel pair, together with high entanglement quality. Polarization and energy-time encodings are characterized through state tomography and two-photon interference measurements, yielding fidelities, purities, and visibilities exceeding 96 % over multiple wavelength channels. The stability and reproducibility of the source are further evaluated through long-duration operation in a network environment. These results demonstrate that the proposed Sagnac source constitutes a practical and scalable building block for future plug-and-play quantum communication and quantum networking platforms.

Heterogeneous Optically-Detected Spin-Acoustic Resonance in Solid-State Molecular Thin-film

Authors: Kuan-Cheng Chen, Yongqiang Wen, Xiaotian Xu, Max Attwood, Jingdong Xu, Chen Fu, Sami Ramadan, Shang Yu, Sandrine Heutz, Mark Oxborrow

Published: February 9, 2026

We report an implementation of spin-acoustic resonance in pentacene thin films integrated on a high-quality-factor (high-Q) surface acoustic wave (SAW) resonator on a lithium niobate substrate. Heterogeneous optically detected spin-acoustic resonance (HODSAR) is an optically detected spin-resonance measurement in which the resonant drive is delivered mechanically by a surface acoustic wave (SAW). By leveraging the photo-excited triplet state of pentacene at room temperature, we demonstrate coherent spin manipulation via acoustic driving under zero externally applied magnetic field. The heterogeneously integrated device, referred to as HODSAR, utilizes spin-phonon coupling to achieve mechanically driven, zero-field spin resonance, opening avenues for room-temperature mechanically addressable spin control and device integration. We show that the high-Q multimode response of the SAW resonator enables spectrally selective acoustic addressing of triplet transitions near 105 MHz. Coherent control is evidenced by Rabi oscillations, with a Rabi frequency that increases linearly with the square root of the applied RF input power over the measured drive range, consistent with driven two-level dynamics under acoustic excitation. These results establish spin-acoustic resonance in a heterogeneously integrated molecular thin-film platform and provide a quantitative basis for benchmarking mechanically mediated spin control.

Andreev terahertz radiation generators

Authors: N. T. Bagraev, L. E. Klyachkin, S. A. Kukushkin, A. M. Malyarenko, A. V. Osipov, V. V. Romanov, N. I. Rul, K. B. Taranets

Published: February 9, 2026

The electrical, magnetic and optical properties of edge channels consisting of spin circuits that contain single carriers in nanostructures of silicon, silicon carbide and cadmium fluoride are investigated. It is demonstrated that due to the presence of chains of negative-U dipole centers at the boundaries of the spin circuits, the latter are Andreev molecules for generating terahertz radiation.

Quantization-aware Photonic Homodyne computing for Accelerated Artificial Intelligence and Scientific Simulation

Authors: Lian Zhou, Kaiwen Xue, Amirhossein Fallah, Lijin Liu, Chun-Ho Lee, Kiwon Kwon, Clayton Cheung, Yuan Li, Yue Yu, Yun-Jhu Lee, Songlin Zhao, Ryan Hamerly, Edo Waks, Dirk Englund, Constantine Sideris, Mengjie Yu, Zaijun Chen

Published: February 9, 2026

Modern problems in high-performance computing, ranging from training and inferencing deep learning models in computer vision and language models to simulating complex physical systems with nonlinearly-coupled equations, require exponential growth of computational resources. Photonic analog systems are emerging with solutions of intrinsic parallelism, high bandwidth, and low propagation loss. However, their application has been hindered by the low analog accuracy due to the electro-optic distortion, material nonlinearities, and signal-to-noise ratios. Here we overcome this barrier with a quantization-aware digital-photonic mixed-precision framework across chiplets for accelerated AI processing and physical simulation. Using Lithium Niobate photonics with channel equalization techniques, we demonstrate linear multiplication (9-bit amplitude-phase decoupling) in homodyne optical logics with 6-bit precision at the clock rate of 128 giga-symbol-per-second (128 GS/s), enabling AI processing with 6 ns latency. Codesign hardware-algorithms, including iterative solvers, sparse-dense quantization, and bit-sliced matrix multiplication, explore photonic amplitude and phase coherence for complex-valued, physics-inspired computation. In electromagnetic problems, our approach yields 12-bit solutions for partial differential equations (PDEs) in scattering problems that would conventionally require up to 32-bit and often even 64-bit precision. These results preserve digital-level fidelity while leveraging the high-speed low-energy photonic hardware, establishing a pathway toward general-purpose optical acceleration for generative artificial intelligence, real-time robotics, and accurate simulation for climate challenges and biological discoveries.

Systematic Analysis of Ferroelectric Domain Dynamics in Periodically Poled Lithium Niobate Waveguides Using Two-Photon Microscopy and Digital Imaging Processing

Authors: Jiuyi Zhang, Christopher Cullen, Matthew Konkol, Peng Yao, Timothy Creazzo, Janusz Murakowski, Ruidong Xue, Xiaofeng Zhu, Md Omar Faruk Rasel, Yash Kabra, Dennis Prather

Published: February 8, 2026

We present a characterization and analysis methodology suitable for volume production for characterizing and optimizing x-cut thin-film periodically poled lithium niobate (PPLN) devices using two-photon (2P) microscopy with quantitative image processing. This method enables direct extraction of key structural parameters, such as duty cycle, phase-matching behavior, and domain uniformity, across large device sets in a non-destructive manner. By correlating 2P microscopy-derived structural metrics with systematic variations in poling conditions, we establish a scalable, image-driven approach for evaluating and improving PPLN fabrication. The resulting workflow supports wafer-level process development and accelerates the manufacturing and packaging of lithium niobate photonic integrated circuits (PICs).

Emergence of a lithium dip in ~35 Myr "Snake" Open Clusters

Authors: Yun-Yi Zhang, Hai-Jun Tian, Jian-Rong Shi, Cheng-Cheng Xie, Xiang-Ming Yang

Published: February 7, 2026

We report the discovery of a lithium dip (Li-dip) in the stellar "Snake" (age = $35 \pm 5$ Myr), challenging the classical view that Li-dips emerge only at ages $\gtrsim 150$ Myr. Using high-resolution spectra from GALAH DR4 ($R \sim 28,000$) for 211 member stars, we identify a clear depletion feature in a $T_{\mathrm{eff}}$ range of 6200--6800 K with a depth of $ΔA(\mathrm{Li}) \approx 0.40$ dex. Our analysis reveals two key advances: the Li-dip appears $\gtrsim 100$ Myr earlier than the previous observations, and within the dip temperature range, a significant correlation is found between rotational velocity and lithium depletion. Specifically, fast rotators ($v \sin i > 25$ km s$^{-1}$) exhibit stronger lithium depletion than slow rotators ($v \sin i < 25$ km s$^{-1}$). This trend suggests that faster rotators develop stronger rotational shear at the convective-radiative boundary, which enhances turbulent mixing and accelerates lithium destruction. It is also found that the lower temperature edge of the lithium plateau can reach as low as 5500 K for the young open clusters.

Visible dual-comb spectroscopy across more than 100 THz with lithium niobate nanophotonic waveguides

Authors: Carter Mashburn, Kristina F. Chang, Michael J. Wahl, Mathieu Walsh, Daniel I. Herman, Matthew Heyrich, Tsung-Han Wu, Nazanin Hoghooghi, Ryoto Sekine, Luis Ledezma, Emily Jerris, Alireza Marandi, Jerome Genest, Scott A. Diddams

Published: February 6, 2026

Broadband and high-resolution spectroscopy in the visible and ultraviolet is central to advances in multiple fields, including fundamental quantum physics, biology, atmospheric science and astronomy. Traditionally, these measurements are performed with grating or Fourier-transform spectrometers using incoherent light sources. Leveraging coherent light enables powerful frequency-comb-based techniques, but is limited by the technical complexity of efficiently generating broad spectral bandwidths from relatively narrowband and spectrally distant laser sources. Current visible dual-comb spectrometers require implicit compromises between optical bandwidth, experimental simplicity, and acquisition speed. In this work, we introduce a simple and efficient dual-comb spectrometer that converts robust Er:fiber frequency combs from the near-infrared to the ultraviolet and visible with thin-film lithium niobate (TFLN) nanophotonic waveguides. Using real-time signal processing, we retrieve coherently averaged dual-comb spectra over nearly 120 THz of simultaneous bandwidth in the visible with 100 MHz spectral resolution. With these capabilities, we measure the broadband absorption spectrum of molecular iodine (I2), demonstrating the broadest visible spectral coverage of a dual-comb spectrometer to date. Additional measurements of NO2, atomic rubidium, and atomic sodium further illustrate the achievable combination of spectroscopic bandwidth, resolution, and intrinsic frequency accuracy. Our results demonstrate the powerful integration of low-power frequency combs, nonlinear nanophotonics, and digital signal processing to enable a compact, efficient and versatile approach to high-resolution mapping of complex absorption spectra across 500 THz in the UV-visible and near-infrared spectral regions for multiple applications beyond the research lab

Scalable Preconditioners for the Pseudo-4D DFN Lithium-ion Battery Model

Authors: Thomas Roy, Nicholas W. Brady, Giovanna Bucci, Nicholas R. Cross, Victoria M. Ehlinger, Tiras Y. Lin, Hanyu Li, Marcus A. Worsley

Published: February 6, 2026

The pseudo-4D Doyle-Fuller-Newman (DFN) model enables predictive simulation of lithium-ion batteries with three-dimensional electrode architectures and particle-scale diffusion, extending the standard pseudo-2D (P2D) formulation to fully resolve cell geometry. This leads to large, nonlinear systems with strong coupling across multiple physical scales, posing significant challenges for scalable numerical solution. We introduce block-structured preconditioning strategies that exploit the mathematical properties of the coupled system, employing multigrid techniques for electrode-level operators and localized solvers for particle-scale diffusion. Comprehensive scalability studies are performed across a range of geometries, including homogeneous and heterogeneous cubic cells, flattened jelly-roll configurations, and triply periodic minimal surface electrodes, to assess solver robustness and parallel scalability. The proposed methods consistently deliver efficient convergence and enable the solution of battery models with hundreds of millions of degrees of freedom on large-scale parallel hardware.