We have developed a field-deployable vector magnetometer using a small rubidium vapor cell, which is capable of measuring the magnitude and direction of the earth's magnetic field with high accuracy and sensitivity. The magnetometer measures Larmor precession of rubidium atoms using the phenomenon, called synchronous coherent population trapping (SCPT). This gives the advantage of producing a high contrast and narrow linewidth resonance needed for measuring the magnetic field with high accuracy and sensitivity. The magnetometer exhibits sub-nT/√Hz sensitivities in measuring the field components along the three directions.

We present investigations of coherent population trapping (CPT) and Ramsey-CPT interrogations in laser-cooled 87Rb atoms towards the development of a cold atom-based clock.CPT and Ramsey-CPT interrogations are performed by turning off the magneto-optical trap (MOT) and allowing the atoms to freely expand. Ramsey-CPT interrogation is performed in the time-domain by delivering resonant Raman pulses to the atoms separated by a free evolution time which is determined by the atomic expansion time in our system. Our results show promise for improving the clock performance using this cold atom-based apparatus.

No abstract pending ARL review - talk will focus on diamond quantum sensors

We report dual er qubits in two distinct symmetry sites of an epitaxially grown single crystal Y2O3 thin film. Coupling of Er spins to a superconducting microwave resonator and a fiber micro-cavity enables simultaneous optical-spin coherence spectroscopy at millikelvin temperature. At optimal field orientations, over millisecond spin coherence times are observed for Er qubits in both C2 and C3i symmetry sites. Single Er ions in both C2 and C3i sites are addressed optically, respectively at the field configuration where their millisecond spin coherence times are measured. By correlating the spin spectral diffusion and optical dephasing rate of C3i Er qubits, we report a magnetic noise limited spin-optical dephasing rate of only 2.6 kHz, demonstrating significant prospect of Er in epitaxial Y2O3 thin film as a highly coherent spin-photon interface for quantum network.

Quantum computing (QC) is theorized to solve certain important problems much faster than classical computers. The current state of QC, the noisy intermediate-scale quantum (NISQ) era, is limited in the scope of problems it can solve, largely due to the quantity of reliable qubits available to universal quantum operations. And while all available quantum computing systems have their advantages, ion-based systems have been shown to be a reliable option with low infidelity and a capability for universal gating procedure. These advantages are dependent on achieving low crosstalk when addressing ions, a vital challenge for this QC system, particularly when using only bulk optic systems. Here we show a microfabricated planar waveguide which can selectively interact in free space with 8 trapped Ba+ ions. This performance meets or exceeds that of similar waveguides couple to trapped ion systems and shows a reliable method to selectively interact with ions bound by a Paul Trap using imaged waveguide outputs.

In this presentation, I will discuss efforts in the quantum community and at IonQ to develop chip-scale technology to enable higher-performance and more scalable trapped-ion quantum computer systems. The presentation will focus on the benefits and challenges of using this technology today and in the future, and on approaches to ensure successful integration of new quantum technology into commercial quantum computer systems.

General-purpose fault-tolerant quantum computers will utilize millions of physical qubits, thus requiring an underlying qubit technology that can be manufactured at scale. Integrated silicon photonics is an intrinsically scalable and manufacturable platform where all necessary gates are available to manipulate qubits, encoded in photons, with very high fidelity and low noise. In this talk, we will discuss architectures for fault-tolerant quantum computing with photonics in the newly introduced fusion-based quantum computing paradigm. Fusion-based quantum computing presents a new framework for fault-tolerant quantum computation, focused on the efficient integration of quantum error correction and physical-level hardware operation. Its primitives, small, entangled resource states, and projective entangling gates make it particularly useful in an integrated photonics platform, offering significant architectural simplifications and reducing requirements on physical level operations.

Analog quantum simulators rely on programmable quantum devices to emulate Hamiltonians describing various physical phenomenon. Photonic coupled cavity arrays are a promising platform for realizing such devices. Using a silicon photonic coupled cavity array made up of 8 high quality-factor resonators and equipped with specially designed thermo-optic island heaters for independent control of cavities, we demonstrate a programmable device implementing tight-binding Hamiltonians with access to the full eigen-energy spectrum. We report a ~50% reduction in the thermal crosstalk between neighboring sites of the cavity array compared to traditional heaters, and then present a control scheme to program the cavity array to a given tight-binding Hamiltonian.

AIM Photonics offers multiple technology platforms including a full Silicon Photonics MPW, Low Loss Quantum MPW, Sensors MPW, Silicon Photonics Interposer and Electronic Interposer. In this paper, we will present our low loss quantum enabled technology and discuss the approach to enable new materials and novel devices while maintaining the core electrical and optical performance specs of the current technology.

In the ultrafast domain, high intensity applications and quantum information science share common obstacles when it comes to efficient frequency conversion. This talk will cover several recent advances in nonlinear optical frequency conversion that overcome the usual behaviors that limit applications. We will discuss precise, efficient, ultrabroadband frequency translation by adiabatic phase matching and efficient parametric amplification by hybridized wave mixing, and where these concepts may fit in a wide range of future applications.

Tunable external cavity diode lasers (ECDLs) are essential in quantum systems like sensors, clocks, and computers. However, typical ECDLs are lab-oriented and sensitive to environmental factors. DRS Daylight Solutions has developed a compact, robust ECDL with enhanced frequency stability, spanning 369nm to 1800nm, offering mode-hop-free tuning over 50GHz and exceptional free-running linewidth. It demonstrates remarkable stability even under extreme conditions, with features like a hermetically sealed chassis and optional fiber coupling for versatile use in diverse environments and applications, advancing the development of quantum systems.

We describe a CMOS photonic integrated circuit for fully on-chip generation of frequency-bin and polarization- entangled photon pairs. The Sagnac-inspired design uses an on-chip polarization splitter-rotator to bidirectionally pump a microring resonator and generate entangled photon pairs through spontaneous four-wave mixing in frequency bins spaced 38.4 GHz apart with < 6 GHz linewidth. By recombining the counterpropagating outputs into orthogonal polarization modes with a second polarization splitter-rotator, the source outputs polarization Bell states with high fidelity (95% on average for ≥ 10 bins away from the pump) across the C- and L-bands (> 9 THz)—a bandwidth currently limited only by the passband of our wavelength-selective switch. Our source has applications in flex-grid entanglement distribution, where adjacent frequency bins may be combined to improve the flux and coincidences received by an end-user. Additionally, the source can support a high density of information per photon pair as a hyperentangled resource in the polarization and frequency-bin degrees of freedom.

With recent and rapid progress, compound semiconductor on insulator (CSOI) photonics is transforming quantum technologies by providing new functionalities and capabilities not possible with traditional, silicon-based photonics. In this talk, I will discuss how we can leverage the strong nonlinearities and low propagation loss of CSOI photonics to engineer and manipulate complex quantum photonic states on chip. I will present recent results on creating indistinguishable arrays of entangled-pair and squeezed light sources pumped with continuous wave and pulsed excitation, on-chip line-by-line quantum frequency comb shaping, and tunable microring resonator arrays for frequency bin qudits.

In this talk I will present a novel differential amplification scheme for quantum homodyne detection which increases the signal-to-noise for the detection of a quantum signal by 3dB relative to previous known methods. I will also present an open-source quantum photonic design suite used to model this and other photonic integrated circuits.

Quantum Photonic Integrated Circuits (Q-PICs) chips are playing a pivotal role in achieving the dense integration necessary for scalable quantum technologies. In this talk, I will introduce essential Q-PIC components, notably nonlinear waveguide photon sources that operate across a broad spectrum, extending from visible to telecom wavelengths. I will also delve into the development of efficient circuitry for manipulating photonic qubits, in particular, thermo-optic phase shifters that operate using just a milliWatt and high performance Silicon electro-optic modulators. I will also discuss the packaging of Q-PICs, in particular, low-loss fiber-to-chip coupling, flip-chip integration with electronic interconnects and heterogeneous integration of nonlinear and III-V materials using Micro-Transfer Printing and Photonic Wire Bonding.

Nonlinear optics plays an important role in the operation and networking of optical quantum systems. Frequency conversion processes are often used in producing laser light at relevant wavelengths for control and interrogation of quantum systems, in creating frequency combs for precision measurements and optical clock readout, and in linking quantum systems to and from telecommunications-band optical fiber networks. Recent development of robust photonic integrated circuit (PIC) platforms possessing strong optical nonlinearities has brought some of this functionality to the chip-scale, with low-power, continuous-wave nonlinear optics in particular possible in microresonator geometries. In this talk, I will review my lab’s progress in developing Kerr nonlinear microresonators for the above applications. I will discuss how these systems can be tailored for low-noise, nonlinear light generation in the visible, for octave-spanning frequency combs suitable for deployable optical clocks, and for networking of quantum nodes.

Quantum dots (QDs) have emerged as promising quantum light sources due to their ability to generate single photons and their compatibility with well-established semiconductor technologies. Meanwhile, nonlinear photonics utilizing aluminum gallium arsenide (AlGaAs) or indium gallium phosphide (InGaP) on insulator waveguides facilitates the manipulation of photons through quantum frequency conversion (QFC) and spontaneous parametric down-conversion (SPDC). It is of significant interest to integrate QDs and nonlinear materials on large-diameter silicon photonic wafers to build quantum networks leveraging scalable photonics manufacturing.

Here we present an overview of quantum networking research at ARL

Integrated photonics has grown in the last decade to fill the market with classical devices that offer tremendous SWaP benefits over conventional bulk optics and fiber components. For quantum systems the device losses were still too large to allow for large system scaling as well as too narrow a transparency window to cover all the qubit technologies. Over the last couple years, both industry and government laboratories have worked closely with commercial institutions to address both issues by reducing the waveguide losses and initiating the process to include ultrawide-bandgap photonic materials into the fabrication process. These research areas, the results, and the next steps forward for integrating other materials and qubit systems into the platform will be the subject of my talk.

The hardware limitations of conventional electronics in deep neural network (DNN) applications have spurred exploration into alternative architectures, including optical accelerators. This work investigates the scalability and performance metrics—such as throughput, energy consumption, and latency—of various optical and opto-electronic architectures, with a focus on recently developed hardware error correction techniques, in-situ training methods, initial field trials, as well as extensions into DNN-based inference on quantum signals with reversible, quantum-coherent resources.