Ultra-violet (UV) and near-UV wavelengths are necessary for many important optical transitions for quantum technologies and various sensing mechanisms for biological and chemical detection. However, all well-known photonic platforms have excessively high losses in the UV, which has prevented photonic integrated circuits (PICs) being used to address these and other important application spaces. Photonic waveguides using low-loss alumina cores have emerged as a promising solution because of almunia's large optical bandgap and the high quality of films enabled by atomic layer deposition. However, to the best of our knowledge, active alumina PICs have only been realized using thermo-optic tuning, which precludes switching speeds shorter than one microsecond, high circuit densities, and cryogenically compatible operation. Here, we introduce a CMOS-fabricated, piezo-optomechanical PIC platform using alumina waveguides with low optical losses at UV wavelengths and aluminum nitride piezoelectric strain actuators, which solves the issues associated with thermal tuning. We demonstrate a high-performance, reconfigurable optical filter operating at wavelengths as low as 320 nm. The filter has a 6 nanosecond switching time, a loaded linewidth of 3.3 GHz, tuning rate of -120 MHz/V, and a hold power less than 20 nW.

Acoustoelectric interactions occur when free carriers in a semiconductor interact with the fields of an acoustic wave in a piezoelectric medium. These interactions can amplify acoustic waves, as well as give rise to extremely large phononic nonlinearities and strong non-reciprocal effects. Despite the tremendous progress in the last ten years, the field is entirely dependent on analytical and perturbative solutions for the two simplest arrangements of piezoelectric-semiconductor materials. While these models have allowed the field to advance substantially, new geometries are arising that do not satisfy assumptions integral to these canonical models. These models rely on simplifying assumptions that remove the tensorial nature of the materials, restricting analysis to plane wave and perturbative solutions. Such restrictions fails to capture the non-perturbative nature of the acoustoelectric effect, illustrating the need for more advanced computational methods to analyze acoustoelectric systems. We develop, for the first time, a finite element method (FEM) model to solve for acoustoelectric interactions in arbitrary geometries. We use the model to verify existing results for amplification, dispersion, and non-reciprocity obtained from the canonical models. We then examine the acoustoelectric effect in two geometries not covered by the canonical models: a thin piezoelectric film placed above a semiconductor substrate and a fully 2D waveguide under a thin semiconductor layer. This work lays the foundation for accurate modeling of arbitrary acoustoelectric geometries such as those currently being developed for all-acoustic radio frequency (RF) signal processing, acoustoelectrically enhanced photonic devices, and quantum acoustoelectric devices.

We demonstrate a CMOS-fabricated AlN-on-SOI electro-optomechanical microdisk resonator. Sweeping the DC bias between +/- 10 V provides electrical control over the 17.9 MHz mechanical mode's dissipation, enabling a 33% reduction in its linewidth.

Acceleration sensing underlies a wide range of commercial and scientific technologies, yet optomechanical accelerometers, despite their impressive displacement sensitivity, have not reached practical viability for commercial or defense applications. Most optomechanical sensors are sensitive to external non-inertial forces, vibrations, temperature drift, and wavelength drift. In the case of the photonic integrated optomechanical accelerometers, these effects are primary sources of bias instability and limit the ability of these sensors to attain navigation-grade performance. We present a photonic integrated, fiber-packaged optomechanical accelerometer that advances toward navigation-grade accelerometry, especially with regard to bias instability. Displacement readout is provided by an integrated differential strain-sensing Mach–Zehnder interferometer attached to an ultra-rigid, bulk-micromachined proof mass with a 93.4 kHz fundamental resonance frequency (22.5 pm/g displacement). The high displacement sensitivity provides a 4.2 μg/Hz acceleration resolution over a 66 kHz operational bandwidth. Furthermore, we show that the combination of high rigidity and intrinsic differential optical readout makes the device insensitive to the common causes of bias instability, and we measure a bias instability of 6.3 μg at 243 s. The device operates over a temperature range of greater than 20 °C and a 17 nm optical bandwidth, eliminating the need for sophisticated laser sources, providing a pathway to reduced size, weight, and power. Our device is well suited for operation in practical environments and establishes a pathway for chip-scale optomechanical accelerometers to approach and potentially surpass the performance of existing chip-scale accelerometer platforms.

We present a strategic plan for neutral atom quantum computation, bringing together hardware development and theory advancements to achieve the goal of practical quantum advantage. The concept of practical quantum advantage is defined, along with how to verify claims of advantage, and approaches to designing quantum algorithms that deliver practical advantage. Future directions for neutral atom quantum processor hardware are described: scaling-up system size, Qubit encodings and atomic platforms, going further below threshold with neutral-atom logical-qubit performance, continuous reloading of qubits, and fast readout. We also explore opportunities for scalable integrated photonic control technologies. Alongside hardware advancements, new developments in quantum error correction and compilation of quantum circuits are proposed. Finally, we examine the opportunity of networking multiple neutral atom quantum processors together to perform distributed quantum computing and overcome possible limitations of a single system.

We demonstrate a high-volume CMOS foundry fabricated, piezoelectrically actuated, slotted W1 photonic crystal cavity with optical resonance tuning of 3.87 THz using 40V bias, increasing the optomechanical coupling rate from 160 GHz/nm to 500 GHz/nm.

Surface acoustic waves (SAWs) enable a wide array of technologies, including radiofrequency filters1,2, chemical and biological sensors3-5, acousto-optic devices6-8, acoustic control of microfluidic flow in lab-on-a-chip systems9-11 and quantum phononics12-19. Although numerous methods exist for generating SAWs, they each have intrinsic limitations that inhibit performance, operation at high frequencies and use in systems constrained in size, weight and power. Here we present a completely solid-state, single-chip SAW phonon laser consisting of a lithium niobate SAW resonator with an internal, d.c. electrically injected and broadband semiconductor gain medium with <0.15 mm2 footprint. Below the threshold bias of 36 V, the device behaves as a resonant amplifier, and above it exhibits self-sustained coherent oscillation, linewidth narrowing and high output powers. A continuous on-chip acoustic output power of up to -6.1 dBm is generated at 1 GHz with a resolution-limited linewidth of <77 Hz and a carrier phase noise of -57 dBc Hz-1 at 1 kHz offset. Through detailed modelling, we show pathways for improving the performance of these devices, including mHz linewidths, high power efficiencies and footprints under 550 μm2 at 10 GHz. This demonstration paves the way for ultrahigh-frequency SAW sources on-chip and highly miniaturized SAW-based systems that can be operated without an external radiofrequency source.

We demonstrate wafer-scale monolithic integration of an optomechanical MEMS photonic integrated circuit platform on a commercial high-density Electronic Integrated Circuit backplane with 2 million electrical connections. We discuss suitability of VLSI hybrid spin-photon quantum computing.

A seamless chip-to-world photonic interface enables broad advancements in optical ranging, display, communication, computation and quantum information science. The ideal solution enables two-dimensional scanning of a diffraction-limited beam from anywhere on a photonic integrated circuit to a large number of resolvable spots. Current beam-scanning technologies are limited by a fundamental trade-off: photonic-integrated-circuits with diffractive optics offer scalability but have poor mode quality1,2, whereas inertially limited micromechanical scanners provide high-quality beams but lack scalable integration3,4. Here we report a photonic ski-jump-a nanoscale waveguide monolithically integrated on a piezoelectric cantilever-to overcome these limitations. It passively curls ~90° out-of-plane within a less-than-0.1 mm2 footprint, emits a submicrometre, broadband diffraction-limited beam, and exhibits kilohertz-rate mechanical resonances with quality factors of over 10,000. Fabricated in a volume complementary metal-oxide-semiconductor (CMOS) foundry, our device enables scalable two-dimensional beam scanning. Driven on-resonance at CMOS-level voltages, it achieves a footprint-adjusted spot rate of 68.6 mega spots s-1 mm-², exceeding state-of-the-art micro-electro-mechanical systems mirrors by more than 50-fold, which is sufficient for one million pixels at 100 Hz from an approximately 1.5 mm diameter footprint. We demonstrate full-colour image and video projection, and single-photon initialization and readout from silicon vacancy centres in diamond. Finally, by demonstrating uniformity across a 64 ski-jump array, we establish a pathway to achieving greater than one gigaspot resolution at kilohertz rates within a sub-5-cm-diameter footprint, creating a seamless optical pipeline between integrated photonic processors and the free-space world.

We demonstrate first-ever acoustoelectrically enhanced acousto-optic modulation for integrated RF-optical links. The lithium niobate and silicon nitride integrated platform achieves an acoustoelectrically enhanced half-wave voltage length product of V π L = 0.038 V-cm.

The quantum vacuum can assume thermal properties as a consequence of system kinematics, highlighting the nuance of our definition of particles in quantum field theory. Here, we explore this phenomenon in acoustoelectric systems, involving the interaction of phonons and plasmons, where the charge carriers drift at a constant velocity exceeding the speed of sound. Through an open quantum systems analysis, we show that the acoustoelectric quantum vacuum acquires a thermal character with a temperature defined by the drift velocity and the phonon wavevector. Realistic parameters yield effective temperatures of several Kelvin, establishing acoustoelectric systems as a promising platform for the investigation of quantum vacuum effects.

We model the noise factor for Brillouin linear amplifiers for a vast parameter space. Previous inferred understandings of the Brillouin noise factor ( F ≈ 1 + n th ) overestimate the noise when there is significant phonon propagation.

The stringent demands of photonic quantum computing protocols motivate photonic integrated circuit (PIC) platforms with passive optical properties such as extremely low losses and correspondingly large circuit depths, as well as active optical properties such as high reconfiguration rates, low power dissipation, and minimal crosstalk. At the same time, many quantum photonic resource state generators, such as single-photon sources and quantum memories, require operation in the visible wavelength range. These requirements make the passive optical properties of CMOS-fabricated, ultralow-loss, low-confinement silicon nitride waveguides especially attractive. However, the conventional active properties of these systems based on thermo-optic modulation are plagued by high levels of crosstalk, slow modulation rates, and high power dissipation. Although there have been recent demonstrations of CMOS-fabricated, visible wavelength, piezo-optomechanical PICs that solve the above challenges associated with implementing active functionality, these have made use of high-confinement waveguides with currently demonstrated losses of order 0.3-1 dB/cm, precluding circuit depths required for scalable quantum algorithms. Here, we demonstrate that combining piezo-optomechanical actuation with a low-confinement, ultra-low loss silicon nitride platform addresses the scalability challenge while enabling high-performance active functionality at visible wavelengths. This platform achieves a propagation loss 0.026 dB/cm at 780 nm, modulation bandwidths in the MHz range, and a phase shifter voltage-length product (V_πL) of approximately 2.8 V·m and negligible hysteresis. We further demonstrate reconfigurable Mach-Zehnder interferometers based on spiral phase shifters with 0.63 dB loss per phase shifter.

We report compact, on-chip visible polarizers with simulated extinction ratios >20 dB and losses <1 dB at 620 nm illumination. Designs on a wafer-scale CMOS-compatible SiN photonic integrated circuit platform exhibit extinction ratios >10 dB.

Programmable photonic integrated circuits (PICs) have recently emerged as an important technology for quantum information science and artificial neural networks. In particular, PICs with microelectromechanical-based modulators have the advantages of voltage-based control, ultra-low-energy consumption, cryogenic compatibility, and CMOS-foundry support. Here, we report a cantilever optical modulator that utilizes hybrid piezoelectric and electrostatic tuning forces together on a monolithic silicon nitride (SiN) PIC platform. The device achieves actuation of visible-wavelength light with quasi-static tuning up to 10 kHz at 1.5 Vπ-cm as well as high-speed (>20 MHz) AC modulation with dynamically adjustable (25–40 MHz) mechanical resonances. We report the physics of how geometric nonlinearities, such as capacitive pull-in, give rise to suspended and contacted cantilever modes. These reversible operating regimes generate different strain profiles and boundary conditions, which are responsible for the active tuning of the mechanical resonances. Our proof-of-concept electrostatic–piezo modulator shows promising potential in large-scale programmable PICs applied to high-speed optical switching and optomechanical sensing.

Next-generation photonic architectures for AI, sensing, and quantum computing require thousands to millions of reprogrammable photonic devices on a chip[1]. The monolithic integration of Electronically-backed Photonic Integrated Circuits (EPICs) allows for very high density electrical interconnection and electronic drivers that can scale with photonics. Piezo-optomechanical photonic integrated circuits (POMPICs) offer low power consumption, high speed modulation, cryogenic compatibility and broadband optical transparency from ultraviolet to infrared wavelengths[2,3], but have not been demonstrated with monolithically integrated CMOS electronics. Here, we show a fully monolithic, all-CMOS fabricated platform for POMPICs co-fabricated with commercial control electronics. 200 millimeter photonic wafers are constructed directly on completed CMOS driver wafers by back-end-of-line processing, connecting integrated piezoelectric actuators under broadband silicon nitride waveguides to a high-density digital backplane comprising >2 million electrical connections per die with 6.4x6.4 micron electrode pitch. We introduce segmented POMPIC components as Photonic Digital-to-Analog converters (PDACs) that convert low-voltage digital electronic signals to multi-bit analog optical phase and amplitude modulation, and we demonstrate parallel control of optical phase shifters, Mach-Zehnder interferometers, optical routing trees, and tunable ring resonators using a standard HDMI interface to program CMOS electronics. We test multiple reticles and perform electronic and photonic characterization across the entire wafer to establish uniformity and yield, demonstrating wafer-scale integration of POMPICs on an electronic backplane and enabling dense, scalable electronic control of piezo-optomechanical circuits.

We analyze stress-engineered photonic "ski-jump" scanning waveguide micro-cantilevers, confirming good die-scale uniformity, wide thermal tunability (81% curvature, 75% frequency), and robust operation under 20-80 Hz vibration. Results validate their potential for large-scale 3D photonic systems.

We demonstrate a programmable photonic memristor with up to 4-bit modulation and device durability of over 100 million read-write cycles on a scalable, CMOS-compatible platform utilizing electrostatic-piezo MEMS tuning mechanisms.

A fundamental challenge in optics has created a paradox for augmented reality: while >48-megapixel cameras are mass-produced in modules smaller than a dime, no displays of comparable resolution and size exist. This is because cameras are lens-limited, while displays are limited by the etendue and size of their light source. We present a light engine architecture based on a "photonic ski-jump" array: a CMOS-fabricated, piezo-actuated scanning waveguide platform that provides a programmable grid of diffraction-limited point sources. By tiling similar to 250 scanners on a single 5x5 mm chip, we can pair the array with mature, low-cost smartphone camera micro-optics to form a compact, ultra-high-resolution projector with a path to >30-megapixel spot grids. We have proven core components of this architecture, fabricating uniform 64-scanner arrays, demonstrating two-dimensional image/video projection, and demonstrating high-quality beam relay through a commercial iPhone camera lens. Together these results outline a path to a complete projector system with a volume under 1 cc, enabling true high-resolution, all-day wearable AR glasses.

We describe all-CMOS-fabricated, piezo-optomechanical, acousto-optic photonic integrated circuits that convert high-power continuous-wave visible laser light to gigahertz-frequency amplitude-modulated signals that can provide gate operations for trapped-atom and ion qubits.