Atoms can be controlled by manipulating their internal states using agile, quiet and reliable laser sources. An external-cavity diode laser (ECDL) is a crucial enabling technology to realize such laser sources since it allows for the narrowing of the linewidth of a laser diode and precise tuning of the laser frequency. This project aims to miniaturize the external cavity using a photonic integrated circuit (PIC) (i.e., a single chip), which will increase the reliability and functionality of the optical frequency source for quantum experiments. A PIC ECDL will be designed and fabricated using aluminum nitride (AlN). Since several atomic transitions of interest in quantum applications are in the visible spectrum, AlN is an ideal material due to its large bandgap that allows for low-loss waveguide propagation. AlN also enables key functionality for preparing narrow linewidth and agile optical frequencies. Thus, an AlN waveguide will be fabricated and tested to ensure low waveguide losses at visible wavelengths. An external cavity feedback laser will be fabricated by coupling a laser diode directly into the AlN waveguide. A micro-ring resonator feedback circuit will be used to select and narrow the laser output. The light will be further coupled into fibre optics for delivery to atoms in a vacuum chamber, demonstrating the viability of using PIC ECDLs to interact with atomic energy levels. This AlN PIC ECDL would be a compact optical frequency source that could help enhance existing quantum experiments, enable experiments currently unviable with bulk optical setups and allow for the translation of quantum atomic technologies out of the laboratory (i.e., large-scale quantum computation, high-precision gravimeters for resource mapping and portable optical atomic clocks).
Figure 1. A conceptual render of an external cavity diode laser in an aluminum nitride integrated photonic circuit.
Related Content

Rydberg Atom Array Quantum Simulator
Summary Quantum simulators enable probing the static and dynamic properties of correlated quantum many-body systems that would otherwise be numerically inaccessible using classical simulators. We are developing quantum simulators based on arrays of neutral atoms excited to Rydberg states. Such Rydberg atom arrays are advantageous for simulating the dynamics of interacting spin systems (Ising spin […]
February 27, 2020

Cryo-CMOS to Control and Operate 2D Fault-Tolerant Qubit Network
Summary Large-scale, fault-tolerant quantum computation requires precise and stable control of individual qubits. This project will use complementary metal-oxide-semiconductor (CMOS) technology to provide a cost-effective scalable platform for reliable and high-density control infrastructure for silicon spin qubits. We will use sub-micron CMOS technology to address device and circuit-level challenges and explore the integration of […]
June 14, 2018
Novel Superconducting Qubits for Error-Corrected Processors
Summary In this project, we develop novel superconducting qubits for error-corrected processors to enable large-scale quantum computing. Our design efforts will specifically target error-corrected architectures through a variety of paths. Possible features will include built-in parity measurements and the use of bosonic codes, such as Fock state and Cat codes, as our starting focus. Early […]
June 26, 2019

Ultrafast Dynamical Studies of Valley-Based Qubits
Summary As monolayers, transition metal dichalcogenides (TMDCs) – such as tungsten diselenide (WSe2) – become direct-bandgap semiconductors capable of emitting light. Compared to conventional direct-bandgap semiconductors, such as III-V semiconductors like GaAs, excitons (quasiparticles made of an electron hole bound with an electron) and single-layer TMDCs (SL-TMDCs) have much stronger binding energy. Excitons and […]
June 29, 2018