arXiv subjects

Andrew D. Beyer

Publications and source records attributed to Andrew D. Beyer.

At least 19 recordsLinked to original sources

arXiv2026

Enhanced Mid-Infrared Single-Photon Detection with Antenna-Coupled Superconducting Nanowires

Scaling the photon-detection area of superconducting nanowire single-photon detectors (SNSPDs) has traditionally been achieved by nanowire meandering. However, material inhomogeneities and fabrication-induced defects, such as line-edge roughness, increase with nanowire length, leading to reduced internal photon-detection efficiency and elevated dark-count rates. This trade-off becomes increasingly pronounced as nanowires are scaled to sub-100 nm widths and sub-5 nm thicknesses required for mid- to far-infrared sensitivity. Here, we demonstrate an antenna-coupled SNSPD architecture that enhances the effective photon-detection area without increasing nanowire length. A crossed bowtie antenna integrated with an 80 nm-wide, 3 nm-thick WSi nanowire yields 15.7$\times$ increase in effective detection area at 7.4 $μ$m compared to a bare nanowire of identical geometric footprint, while maintaining the same internal detection efficiency and dark-count rate. Antenna coupling provides a scalable approach to increasing photon-detection area while reducing the noise-equivalent power, offering performance benefits for applications in astronomy, biological imaging, and molecular spectroscopy.

physics.optics↗

arXiv2026

Low-Frequency Noise Performance of Microstrip-Coupled Lumped-Element Aluminum KIDs using Hydrogenated Amorphous Silicon Parallel-Plate Capacitors for NEW-MUSIC

We present measurements of the low-frequency noise of microstrip-coupled, lumped-element aluminum kinetic inductance detectors that use hydrogenated amorphous silicon parallel-plate capacitors (Al/a-Si:H MS-PPC-LEKIDs), which are under development for the Next-generation Extended Wavelength Multiband Submillimeter Inductance Camera (NEW-MUSIC). We show that, under dark conditions, these devices are generation recombination (GR) noise dominated down to 0.1 Hz and, under optical load, they are likely dominated by GR and photon noise down to tenths of a Hz and possibly lower, both in spite of the use of a-Si:H PPCs. Our measurements set limits on the low-frequency two-level-system (TLS) noise of the a-Si:H material that are consistent with higher frequency measurements in the 0.1-10 kHz regime. These results establish that our MS-PPC-LEKID design for NEW-MUSIC will be photon-noise-limited under a range of observing conditions and, more generally, that a-Si:H PPC-KIDs are a viable new detector technology for even low modulation-rate applications such as astronomy.

astro-ph.IM↗

arXiv2026

Quantum Parity Detectors: a qubit based particle detection scheme with meV thresholds for rare-event searches

The next generation of rare-event searches, such as those aimed at determining the nature of particle dark matter or in measuring fundamental neutrino properties, will benefit from particle detectors with thresholds at the meV scale, 100-1000x lower than currently available. Quantum parity detectors (QPDs) are a class of proposed quantum devices, extending recent work on superconducting qubit sensors, that exploit the fingerprints of single quasiparticle tunneling across a coherent weak-link as their detection concept. As envisioned, phonons generated by particle interactions within a crystalline substrate cause an eventual quasiparticle cascade within a surface-patterned superconducting qubit element. This process alters the fundamental charge parity of the device in a binary manner, which can be used to deduce the initial properties of the energy deposition. This work lays out multiple resonator coupled readout schemes depending on qubit architecture, provides an analytic formulation for reconstructing sensor energies, and details strategies for multiplexing large arrays of sensors. We further compute the sensitivity of QPDs and detail an R&D pathway to demonstrating sub-eV energy deposit thresholds.

physics.ins-det↗

arXiv2026

Superconducting Parallel-Plate Resonators for the Detection of Single Electron Spins

We introduce a multilayer superconducting microwave resonator with sub-Ohm impedance optimized for high coupling strength to single electron spins. The design minimizes the magnetic far-field and therefore achieves a Purcell factor $F_P > 10^{15}$. We show several ways to fabricate this type of resonator and present resonators with an intrinsic $Q$-factor exceeding $2 \cdot 10^4$ at the single-photon level. We further characterize these resonators in magnetic fields up to $500 \, \text{mT}$. Finally, we evaluate the impact of the achievable Purcell factor on single-spin detection through photon counting and dispersive readout.

quant-ph↗

arXiv2025

Improved Modeling of Quasi-Static Thermal and Optical Response of Lumped-Element Aluminum Manganese KIDs

We report on the optical characterization of the AlMn kinetic inductance detectors (KIDs) in development for use in the Next-generation Extended Wavelength-MUltiband Sub/millimeter Inductance Camera (NEW-MUSIC) on the Leighton Chajnantor Telescope (LCT). NEW-MUSIC will cover 80-420 GHz, split into six spectral bands, with polarimetry. This broad spectral coverage will enable study of a range of scientific topics such as the accretion and feedback in galaxies and galaxy cluster evolution via the Sunyaev-Zeldovich effect, the transient synchrotron emission from the explosive deaths of massive stars and other time-domain phenomena, and dusty sources from low to high redshift (with polarization). Al KIDs have already been demonstrated for bands 2-5. AlMn KIDs will be used for the 90~GHz band, as Al's pair-breaking energy is too high. However, AlMn has only barely been explored as a KID material. To this end, we first improved the modeling techniques used for Al KIDs within BCS theory by eliminating the use of analytical approximations for the expressions of the complex conductivity and found these changes reduced fit parameter degeneracy in the analysis of AlMn. Then, we tested the addition of a gap smearing parameter, a standard extension to BCS theory in use for high kinetic inductance materials, and found it did not improve the fits.

astro-ph.IM↗

arXiv2025

Assessing the operating characteristics of an ion-milled phonon-mediated quantum parity detector

Phonon sensitive superconducting qubits promise to provide sub-eV energy deposit thresholds, useful for future rare-event experiments looking for interactions from dark matter and neutrinos. We detail here engineering results from a Quantum Parity Detector (QPDs), one of a class of phonon sensitive qubits, and, as a first measurement, show that this device has a quiescent quasiparticle density of $1.8 \pm 0.8 μ\mathrm{m}^{-3}$, in line with expectation. We also outline an argon ion-mill process for multi-step Josephson Junction fabrication, expanding the sparse literature on this topic, which proves useful in avoiding secondary parasitic junctions.

physics.ins-det↗

arXiv2025

High-efficiency, high-count-rate 2D superconducting nanowire single-photon detector array

Superconducting nanowire single-photon detectors (SNSPDs) are the current leading technology for the detection of single-photons in the near-infrared (NIR) and short-wave infrared (SWIR) spectral regions, due to record performance in terms of detection efficiency, low dark count rate, minimal timing jitter, and high maximum count rates. The various geometry and design parameters of SNSPDs are often carefully tailored to specific applications, resulting in challenges in optimising each performance characteristic without adversely impacting others. In particular, when scaling to larger array formats, the key challenge is to manage the heat load generated by the many readout cables in the cryogenic cooling system. Here we demonstrate a practical, self-contained 64-pixel SNSPD array system which exhibits high performance of all operational parameters, for use in the strategically important SWIR spectral region. The detector is an 8x8 array of 27.5 x 27.8 μm pixels on a 30 μm pitch, which leads to an 80 -- 85% fill factor. At a wavelength of 1550nm, a uniform average per-pixel photon detection efficiency of 77.7% was measured and the observed system detection efficiency (SDE) across the entire array was 65%. A full performance characterisation is presented, including a dark count rate of 20 cps per pixel, full-width-half-maximum (FWHM) jitter of 100 ps per pixel, a 3-dB maximum count rate of 645 Mcps and no evidence of crosstalk at the 0.1% level. This camera system therefore facilitates a variety of picosecond time-resolved measurement-based applications that include biomedical imaging, quantum communications, and long-range single-photon light detection and ranging (LiDAR) and 3D imaging.

quant-ph↗

arXiv2024

Low two-level-system noise in hydrogenated amorphous silicon

At sub-Kelvin temperatures, two-level systems (TLS) present in amorphous dielectrics source a permittivity noise, degrading the performance of a wide range of devices using superconductive resonators such as qubits or kinetic inductance detectors. We report here on measurements of TLS noise in hydrogenated amorphous silicon (a-Si:H) films deposited by plasma-enhanced chemical vapor deposition (PECVD) in superconductive lumped-element resonators using parallel-plate capacitors (PPCs). The TLS noise results presented in this article for two recipes of a-Si:H improve on the best achieved in the literature by a factor >5 for a-Si:H and other amorphous dielectrics and are comparable to those observed for resonators deposited on crystalline dielectrics.

physics.ins-det↗

arXiv2024

NEW-MUSIC: The Next-generation Extended-Wavelength Multiband Sub/millimeter Inductance Camera

The Next-generation Extended Wavelength-MUltiband Sub/millimeter Inductance Camera (NEW-MUSIC) on the Leighton Chajnantor Telescope (LCT) will be a first-of-its-kind, six-band, transmillimeter-wave ("trans-mm") polarimeter covering 2.4 octaves of spectral bandwidth to open a new window on the trans-mm time-domain frontier, in particular new frontiers in energy, density, time, and magnetic field. NEW-MUSIC's broad spectral coverage will also enable the use of the Sunyaev-Zeldovich effects to study accretion, feedback, and dust content in the hot gaseous haloes of galaxies and galaxy clusters. Six-band spectral energy distributions, with polarization information, will yield new insights into stellar and planetary nurseries. NEW-MUSIC will employ hierarchical, phased arrays of polarization-sensitive superconducting slot-dipole antennas, coupled to photolithographic bandpass filters, to nearly optimally populate LCT's 14' field-of-view with six spectral bands over 80-420 GHz (1:5.25 spectral dynamic range; 2.4 octaves). Light will be routed to Al or AlMn microstripline-coupled, parallel-plate capacitor, lumped-element kinetic inductance detectors (MS-PPC-LEKIDs), an entirely new KID architecture that substantially enhances design flexibility while providing background-limited performance. Innovative, wide-bandwidth, etched silicon structures will be used to antireflection-treat the back-illuminated focal plane. NEW-MUSIC will cost-effectively reuse much of the MUSIC instrument, initially deploying a quarter-scale focal plane capable of the bulk of NEW-MUSIC science followed later by a full-FoV focal plane needed for NEW-MUSIC wide-area survey science.

astro-ph.IM↗

arXiv2024

An SNSPD-based detector system for NASA's Deep Space Optical Communications project

We report on a free-space-coupled superconducting nanowire single-photon detector array developed for NASA's Deep Space Optical Communications project (DSOC). The array serves as the downlink detector for DSOC's primary ground receiver terminal located at Palomar Observatory's 200-inch Hale Telescope. The 64-pixel WSi array comprises four quadrants of 16 co-wound pixels covering a 320 micron diameter active area and embedded in an optical stack. The detector system also includes cryogenic optics for filtering and focusing the downlink signal and electronics for biasing the array and amplifying the output pulses. The detector system exhibits a peak system detection efficiency of 76% at 1550 nm, a background-limited false count rate as low as 3.7 kcps across the array, timing jitter less than 120 ps FWHM, and a maximum count rate of ~ 1 Gcps.

physics.ins-det↗

arXiv2024

Characterization of the low electric field and zero-temperature two-level-system loss in hydrogenated amorphous silicon

Two-level systems (TLS) are an important, if not dominant, source of loss and noise for superconducting resonators such as those used in kinetic inductance detectors and some quantum information science platforms. They are similarly important for loss in photolithographically fabricated superconducting mm-wave/THz transmission lines. For both lumped-element and transmission-line structures, native amorphous surface oxide films are typically the sites of such TLS in non-microstripline geometries, while loss in the (usually amorphous) dielectric film itself usually dominates in microstriplines. We report here on the demonstration of low TLS loss at GHz frequencies in hydrogenated amorphous silicon (a-Si:H) films deposited by plasma-enhanced chemical vapor deposition in superconducting lumped-element resonators using parallel-plate capacitors (PPCs). The values we obtain from two recipes in different deposition machines, 7$\,\times\,10^{-6}$ and 12$\,\times\,10^{-6}$, improve on the best achieved in the literature by a factor of 2--4 for a-Si:H and are comparable to recent measurements of amorphous germanium. Moreover, we have taken care to extract the true zero-temperature, low-field loss tangent of these films, accounting for temperature and field saturation effects that can yield misleading results. Such robustly fabricated and characterized films render the use of PPCs with deposited amorphous films a viable architecture for superconducting resonators, and they also promise extremely low loss and high quality factor for photolithographically fabricated superconducting mm-wave/THz transmission lines used in planar antennas and resonant filters.

physics.ins-det↗

arXiv2024

High-rate multiplexed entanglement source based on time-bin qubits for advanced quantum networks

Entanglement distribution based on time-bin qubits is an attractive option for emerging quantum networks. We demonstrate a 4.09 GHz repetition rate source of photon pairs entangled across early and late time bins separated by 80 ps. Simultaneous high rates and high visibilities are achieved through frequency multiplexing the spontaneous parametric down conversion output into 8 time-bin entangled pairs. We demonstrate entanglement visibilities as high as 99.4%, total entanglement rates up to 3.55e6 coincidences/s, and predict a straightforward path towards achieving up to an order of magnitude improvement in rates without compromising visibility. Finally, we resolve the density matrices of the entangled states for each multiplexed channel and express distillable entanglement rates in ebit/s, thereby quantifying the tradeoff between visibility and coincidence rates that contributes to useful entanglement distribution. This source is a fundamental building block for high-rate entanglement-based quantum key distribution systems or advanced quantum networks.

quant-ph↗

arXiv2024

Hierarchical phased-array antennas coupled to Al KIDs: a scalable architecture for multi-band mm/submm focal planes

We present the optical characterization of two-scale hierarchical phased-array antenna kinetic inductance detectors (KIDs) for millimeter/submillimeter wavelengths. Our KIDs have a lumped-element architecture with parallel plate capacitors and aluminum inductors. The incoming light is received with a hierarchical phased array of slot-dipole antennas, split into 4 frequency bands (between 125 GHz and 365 GHz) with on-chip lumped-element band-pass filters, and routed to different KIDs using microstriplines. Individual pixels detect light for the 3 higher frequency bands (190-365 GHz) and the signals from four individual pixels are coherently summed to create a larger pixel detecting light for the lowest-frequency band (125-175 GHz). The spectral response of the band-pass filters was measured using Fourier transform spectroscopy (FTS), the far-field beam pattern of the phased-array antennas was obtained using an infrared source mounted on a 2-axis translating stage, and the optical efficiency of the KIDs was characterized by observing loads at 294 K and 77 K. We report on the results of these three measurements.

astro-ph.IM↗

arXiv2024

Improvements of readout signal integrity in mid-infrared superconducting nanowire single photon detectors

Superconducting nanowire single-photon detectors (SNSPDs) with high timing resolution and low background counts in the mid infrared (MIR) have the potential to open up numerous opportunities in fields such as exoplanet searches, direct dark matter detection, physical chemistry, and remote sensing. One challenge in pushing SNSPD sensitivity to the MIR is a decrease in the signal-to-noise ratio (SNR) of the readout signal as the critical currents become increasingly smaller. We overcome this trade-off with a new device architecture that employs impedance matching tapers and superconducting nanowire avalanche photodetectors to demonstrate increased SNR while maintaining saturated internal detection efficiency at 7.4 μm and getting close to saturation at 10.6 μm. This work provides a novel platform for pushing SNSPD sensitivity to longer wavelengths while improving the scalability of the readout electronics.

physics.ins-det↗

arXiv2023

Parallel-Plate Capacitor Titanium Nitride Kinetic Inductance Detectors for Infrared Astronomy

The Balloon Experiment for Galactic INfrared Science (BEGINS) is a concept for a sub-orbital observatory that will operate from $λ$ = 25-250 $μ$m to characterize dust in the vicinity of high-mass stars. The mission's sensitivity requirements will be met by utilizing arrays of 1,840 lens-coupled, lumped-element kinetic inductance detectors (KIDs) operating at 300 mK. Each KID will consist of a titanium nitride (TiN) parallel strip absorbing inductive section and parallel plate capacitor (PPC) deposited on a silicon (Si) substrate. The PPC geometry allows for reduction of the pixel spacing. At the BEGINS focal plane the detectors require optical NEPs from $2\times10^{-16}$ W/$\sqrt{\textrm{Hz}}$ to $6\times10^{-17}$ W/$\sqrt{\textrm{Hz}}$ from 25-250 $μ$m for optical loads ranging from 4 pW to 10 pW. We present the design, optical performance and quasiparticle lifetime measurements of a prototype BEGINS KID array at 25 $μ$m when coupled to Fresnel zone plate lenses. For our optical set up and the absorption efficiency of the KIDs, the electrical NEP requirement at 25 $μ$m is $7.6\times10^{-17}$ W/$\sqrt{\textrm{Hz}}$ for an absorbed optical power of 0.36 pW. We find that over an average of five resonators the the detectors are photon noise limited down to about 200 fW, with a limiting NEP of about $7.4\times10^{-17}$ W/$\sqrt{\textrm{Hz}}$.

astro-ph.IM↗

arXiv2023

Quantum entanglement between optical and microwave photonic qubits

Entanglement is an extraordinary feature of quantum mechanics. Sources of entangled optical photons were essential to test the foundations of quantum physics through violations of Bell's inequalities. More recently, entangled many-body states have been realized via strong non-linear interactions in microwave circuits with superconducting qubits. Here we demonstrate a chip-scale source of entangled optical and microwave photonic qubits. Our device platform integrates a piezo-optomechanical transducer with a superconducting resonator which is robust under optical illumination. We drive a photon-pair generation process and employ a dual-rail encoding intrinsic to our system to prepare entangled states of microwave and optical photons. We place a lower bound on the fidelity of the entangled state by measuring microwave and optical photons in two orthogonal bases. This entanglement source can directly interface telecom wavelength time-bin qubits and GHz frequency superconducting qubits, two well-established platforms for quantum communication and computation, respectively.

quant-ph↗

arXiv2023

Parallel Plate Capacitor Aluminum KIDs for Future Far-Infrared Space-Based Observatories

Future space-based far-infrared astrophysical observatories will require exquis-itely sensitive detectors consistent with the low optical backgrounds. The PRobe far-Infrared Mission for Astrophysics (PRIMA) will deploy arrays of thousands of superconducting kinetic inductance detectors (KIDs) sensitive to radiation between 25 and 265 $μ$m. Here, we present laboratory characterization of prototype, 25 -- 80 $μ$m wavelength, low-volume, aluminum KIDs designed for the low-background environment expected with PRIMA. A compact parallel plate capacitor is used to minimize the detector footprint and suppress TLS noise. A novel resonant absorber is designed to enhance response in the band of interest. We present noise and optical efficiency measurements of these detectors taken with a low-background cryostat and a cryogenic blackbody. A microlens-hybridized KID array is found to be photon noise limited down to about 50 aW with a limiting detector NEP of about $6.5 \times 10^{-19}~\textrm{W/Hz}^{1/2}$. A fit to an NEP model shows that our optical system is well characterized and understood down to 50 aW. We discuss future plans for low-volume aluminum KID array development as well as the testbeds used for these measurements.

astro-ph.IM↗

arXiv2023

Low-noise single-photon counting superconducting nanowire detectors at infrared wavelengths up to 29 $μ$m

We report on the extension of the spectral sensitivity of superconducting nanowire single-photon detectors to a wavelength of 29 $μ$m. This represents the first demonstration of a time correlated single-photon counting detector at these long infrared wavelengths. We achieve saturated internal detection efficiency from 10 to 29 $μ$m, whilst maintaining dark count rates below 0.1 counts per second. Extension of superconducting nanowire single-photon detectors to this spectral range provides low noise and high timing resolution photon counting detection, effectively providing a new class of single-photon sensitive detector for these wavelengths. These detectors are important for applications such as exoplanet spectroscopy, infrared astrophysics, physical chemistry, remote sensing and direct dark-matter detection.

quant-ph↗