About

Galan Moody is a Professor in the Department of Electrical and Computer Engineering at UC Santa Barbara. His research interests include Quantum Photonics and Optoelectronics, Integrated Photonics, Quantum Computing, Communications, and Networks, Hybrid Quantum Systems, Quantum Dots, and 2D Materials. He is involved in advancing the understanding and development of quantum photonic technologies, contributing to the fields of quantum information science and integrated photonic systems. His work encompasses exploring novel quantum materials and systems to enable next-generation quantum devices and communication networks.

Research topics

• Physics
• Optoelectronics
• Materials science
• Computer Science
• Optics
• Nanotechnology
• Condensed matter physics
• Quantum mechanics
• Engineering
• Electronic engineering

Selected publications

• Bullseye cavities for large optical enhancement from ultraviolet to near-infrared wavelengths

  Journal of Physics Photonics · 2026-04-22

  articleOpen accessSenior author

  Abstract Optical cavities that provide radiative enhancement and efficient photon collection across a broad spectrum are essential for classical and quantum photonic applications. Many platforms to date have been restricted to the near-infrared (NIR) to telecom spectrum with limited cavity enhancement in the ultraviolet (UV) to NIR wavelength range. Here, we develop a silicon nitride ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msub> <mml:mi>Si</mml:mi> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:msub> <mml:msub> <mml:mi mathvariant="normal">N</mml:mi> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> </mml:msub> </mml:mrow> </mml:mrow> </mml:math> ) bullseye cavity platform optimized for maximal optical enhancement at UV and NIR wavelengths. By utilizing a distributed Bragg reflector designed to satisfy the first- and second-order Bragg conditions, the cavity contains guided modes at NIR and UV wavelengths, respectively. We employ finite-difference time-domain simulations to explore the full device parameter space in which our structure can be optimized for off-chip collection efficiencies exceeding 90% or Purcell factors greater than 50. Additionally, we use these two metrics to perform a global optimization where we can achieve simulated optical enhancements greater than 30 for resonances around 425 nm and 835 nm, the highest values reported to date of any optical cavity designs operating below the telecom O-band. We provide an experimental demonstration that includes a CMOS-compatible fabrication process and reflectometry measurements to characterize the cavity resonances. This platform provides a foundation for strong cavity enhancement and efficient off-chip extraction of a wide range of single-photon emitters spanning UV and NIR wavelengths.

  PublisherDOI

• InGaP-on-insulator Waveguides for Entangled Pair Generation

  2025-09-28

  article

  We demonstrate efficient 1550 nm second-harmonic generation in InGaP-on-insulator waveg-uides and report the first wafer-scale nonlinear measurements. Fabricated devices exhibit loss <2 dB/cm, high thickness uniformity, and a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$d_{14}$</tex> coefficient of 121 pm/V. Observed phase-matching trends expose dispersion-model limitations, informing future CMOS-compatible quantum photonic designs. ©2025 The Author(s)

  PublisherDOI

• Magneto-Optics for Cryogenic Communications and Computing Applications

  2025-06-29

  article

  Leveraging the nonreciprocal phase shift in magneto-optic materials, we demonstrate optical modulation for egress data links from a cryostat and optical memory for in-memory computing. These applications highlight the potential of magneto-optics beyond optical isolation.

  PublisherDOI

• Advanced fabrication techniques for high-performance membrane external-cavity surface-emitting lasers

  2025-03-21

  article

  Membrane-external-cavity surface-emitting lasers (MECSELs) consist of an epitaxial active region directly bonded to at least one transparent heatspreader with external cavity mirrors for feedback. These devices enable significant flexibility in emission wavelength and are amenable to enhanced power scaling via optimized thermal management. In this presentation, we describe novel production techniques based on low-temperature direct bonding with the realization of: i) wafer-scale production of high-performance hybrid MECSELs incorporating a back reflector on one face of a dual-SiC-heatspreader (SiC/epi/SiC) stack and ii) high-yield chip-scale double-bonded diamond devices (diamond/epi/diamond) with the potential for significantly enhanced power scaling in optically-pumped semiconductor disk lasers.

  PublisherDOI

• InGaP Ring Resonators: Prospects for High Squeezing and Beyond

  2025-01-01

  article

  We present a non-degenerate squeezing source generated via spontaneous parametric down-conversion in lossy InGaP ring resonators with 11dB of predicted squeezing using experimentally demonstrated parameters.

  PublisherDOI

• High-Performance Near-Infrared Quantum Emission from Color Centers in hBN

  ArXiv.org · 2025-12-18

  preprintOpen accessSenior author

  Color centers hosted in hexagonal boron nitride have emerged as a highly promising platform for single-photon emission and spin-photon technologies relevant to quantum communication and quantum networking. As a wide-bandgap van der Waals material, hBN can host optically active quantum defects across a broad spectral range. Here, we demonstrate a simple and scalable oxygen-plasma process that reproducibly creates single quantum emitters in hBN with blinking-free zero-phonon lines spanning the near-infrared from 700 up to 971 nm. These emitters combine MHz-level brightness, single-photon purity up to 99.9\%, and ultranarrow cryogenic linewidths down to 2.7~GHz under quasi-resonant excitation, placing them in a particularly attractive regime for quantum photonics. Photostability measurements further reveal resistance to photobleaching, sub-nm spectral stability over long timescales, and near-shot-noise-limited intensity fluctuations. Analysis of the phonon sidebands shows weak vibronic coupling and ZPL-dominated emission, with Debye--Waller factors approaching 50\%. Control experiments together with EDS elemental mapping support oxygen incorporation as a necessary ingredient in activating the NIR emitter population, while first-principles calculations identify O$_N$V$_N$ and O$_N$V$_N$H as the leading defect candidates. These results establish a high-performance NIR quantum-emitter platform in hBN for free-space quantum networking and future integrated quantum-photonic architectures.

  PublisherOA PDFDOI

• Integrated mode-hop-free tunable lasers at 780 nm for chip-scale classical and quantum photonic applications

  APL Photonics · 2025-03-01 · 10 citations

  articleOpen accessSenior author

  In the past decade, remarkable advances in integrated photonic technologies have enabled table-top experiments and instrumentation to be scaled down to compact chips with significant reduction in size, weight, power consumption, and cost. Here, we demonstrate an integrated continuously tunable laser in a heterogeneous gallium arsenide-on-silicon nitride (GaAs-on-SiN) platform that emits in the far-red radiation spectrum near 780 nm, with 20 nm tuning range, &amp;lt;6 kHz intrinsic linewidth, and a &amp;gt;40 dB side-mode suppression ratio. The GaAs optical gain regions are heterogeneously integrated with low-loss SiN waveguides. The narrow linewidth lasing is achieved with an extended cavity consisting of a resonator-based Vernier mirror and a phase shifter. Utilizing synchronous tuning of the integrated heaters, we show mode-hop-free wavelength tuning over a range larger than 100 GHz (200 pm). To demonstrate the potential of the device, we investigate two illustrative applications: (i) the linear characterization of a silicon nitride microresonator designed for entangled-photon pair generation and (ii) the absorption spectroscopy and locking to the D1 and D2 transition lines of 87Rb. The performance of the proposed integrated laser holds promise for a broader spectrum of both classical and quantum applications in the visible range, encompassing communication, control, sensing, and computing.

  PublisherDOI

• Characterization of chromium impurities in <i>β</i>-Ga2O3

  Journal of Applied Physics · 2025-03-14 · 7 citations

  articleOpen access

  Chromium is a common transition-metal impurity that is easily incorporated during crystal growth. It is perhaps best known for giving rise to the 694.3 nm (1.786 eV) emission in Cr-doped Al2O3, exploited in ruby lasers. Chromium has also been found in monoclinic gallium oxide, a wide-bandgap semiconductor being pursued for power electronics. In this work, we thoroughly characterize the behavior of Cr in Ga2O3 through theoretical and experimental techniques. β-Ga2O3 samples are grown with the floating zone method and show evidence of a sharp photoluminescence signal, reminiscent of ruby. We calculate the energetics of formation of Cr from first principles, demonstrating that Cr preferentially incorporates as a neutral impurity on the octahedral site. Cr possesses a quartet ground-state spin and has an internal transition with a zero-phonon line near 1.8 eV. By comparing the calculated and experimentally measured luminescence lineshape function, we elucidate the role of coupling to phonons and uncover features beyond the Franck–Condon approximation. The combination of strong emission with a small Huang–Rhys factor of 0.05 and a technologically relevant host material renders Cr in Ga2O3 attractive as a quantum defect.

  PublisherDOI

• Microscopic Theory of Squeezed Light in Quantum Dot Systems

  ArXiv.org · 2025-08-20

  preprintOpen access

  We present a cavity-QED theory for generating squeezed light from semiconductor quantum dots (QDs) integrated in microcavities. We formulate equations of motion for an inhomogeneously broadened QD ensemble that is incoherently pumped and simultaneously driven by a coherent seed field, solve for steady states, and compute the output-field quadrature variances. The analysis identifies operating conditions that yield amplitude-quadrature squeezing, with photon-number fluctuations reduced below the coherent-state limit and squeezing levels as large as 5 dB attainable with presently accessible QD and cavity parameters using only ~ 1 uW pump power. We further show that quantum correlations originating from four-wave mixing play a dual role: they both shape the gain spectrum and generate squeezing. These correlations constitute the quantum counterpart of the mean-field (semiclassical) mechanisms responsible for self-mode-locking in QD lasers and the ultra-narrow lasing linewidths achieved under self-injection locking.

  PublisherOA PDFDOI

• Fabrication, integration, and control of color centers in hexagonal boron nitride

  2025-03-19

  articleSenior author

  Color centers in hexagonal boron nitride (hBN) are an emerging platform for quantum information applications. When compared with other wide bandgap host materials such as silicon carbide and diamond, a key advantage of hBN is the ability to integrate atomically thin flakes with optoelectronic and photonic devices with simple fabrication techniques. In this talk, we will present recent results on site-controlled integration of emitters with integrated photonic resonators in silicon nitride, coupling of hBN emitters to surface acoustic wave cavity phonons for single-photon modulation and control, and progress on engineering new types of emitters related to oxygen- and carbon-based defects.

  PublisherDOI

Recent grants

• Photonic Integration of Site-Controlled van der Waals Emitters for On-Demand Entangled-Photon Pair Generation

  NSF · $398k · 2020–2023

• CAREER: AlGaAs-on-Insulator Integrated Quantum Photonics

  NSF · $500k · 2021–2026

Frequent coauthors

• Steven T. Cundiff

  175 shared

• Rohan Singh

  87 shared

• Hebin Li

  78 shared

• D. Karaiskaj

  University of South Florida

  76 shared

• Mark E. Siemens

  71 shared

• Alan D. Bristow

  60 shared

• A. Cantarero

  Parc Científic de la Universitat de València

  49 shared

• Jagannath Paul

  49 shared

Labs

• Quantum Photonics LabPI

  Not provided

Education

• PhD, Physics

  University of Colorado