Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session K31: Instrumentation 2: Optical, Thermal, and MoreRecordings Available
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Sponsoring Units: GIMS Chair: Shan Wu, Lawrence Berkeley National Laboratory Room: McCormick Place W-192A |
Tuesday, March 15, 2022 3:00PM - 3:12PM |
K31.00001: Measurement of Phonon Angular Momentum via the Einstein-de Haas Effect, Fiber-Optic Interferometry, and a High-Q Oscillator Matthew Dwyer, Devan Shoemaker, Akhil Sadam, John T Markert We report initial design and use of capacitive and fiber-optic-interferometer systems to measure the predicted[1] macroscopic phonon angular momentum. An oscillating magnetic field is applied to an insulating ferromagnet attached to our single-crystal high-Q double torsional oscillator. By the Einstein-de Haas effect, oscillator displacement measurements compared between liquid-nitrogen-temperatures and those closer to the Debye temperature allow extraction of the phonon angular momentum. We predict a force change of 5 x 10-7 N for a 1 mm3 MgZn ferrite sample, which should be easily measurable. Our oscillator, with a resonance at 13.3 kHz, has a thermal noise limit on the order of 10-15 N/√Hz. With capacitive detection, we achieved a force noise of ~10-8 N/√Hz, and interferometer detection has improved our force sensitivity to about 10-11 N/√Hz. Competing effects are being minimized; for example, induced eddy current momentum can overwhelm the phonon effect for metallic ferromagnets. |
Tuesday, March 15, 2022 3:12PM - 3:24PM |
K31.00002: Reaching the Shock Limit via Synchronous Laser Excitation of Multiple Ultrafast Acoustic Waves Jude Deschamps, Yun Kai, Jet Lem, Ievgeniia Chaban, Alexey Lomonosov, Abdelmadjid Anane, Steven E Kooi, Keith A Nelson, Thomas Pezeril In recent years, controlling emergent phenomena in correlated materials through collective lattice vibrations has attracted more and more attention. Strain engineering methods favoring superconductivity, ferroelectricity, or adequate for tuning excitonic, magnetic, metal-insulator transitions are among the latest examples. Large elastic static strains of several percents can be applied to bulk or nano samples up to the onset of plasticity or fracture. However, the excitation of ultrashort vibrations carrying out large strains to percent levels—the threshold at which many physico-chemical properties of materials would be significantly perturbed—still remains a challenge. Conventional laser-shock experiments, based on single-shot laser absorption in a transducer layer, can generate the strains required, although at the price of irreversible sample damage and noisy data. |
Tuesday, March 15, 2022 3:24PM - 3:36PM |
K31.00003: A wireless, skin-interfaced biosensor for cerebral hemodynamic monitoring in pediatric care Changsheng Wu, Alina Rwei, Wei Lu, John A Rogers, Debra E Weese-Mayer Pediatric patients often suffer from cerebral perfusion complications which are linked to persistent neurodevelopmental impairment and higher risks of death. This work reported a wireless, miniaturized, and mechanically soft, flexible device that supports measurement of cerebral hemodynamics quantitatively comparable to existing clinical standards. The system features a multi-photodiode array and a pair of light-emitting diodes for simultaneous monitoring of systemic and cerebral hemodynamics, with ability to measure cerebral oxygenation, heart rate, peripheral oxygenation, and potentially vascular tone, through the utilization of multiwavelength reflectance-mode photoplethysmography and functional near-infrared spectroscopy. This device enables continuous monitoring of biomarkers critical to pediatric neurodevelopment from the patient's own home and during activities of daily living, which allows doctors to gauge health conditions and influence of a pharmacologic agent in diverse settings, not necessary from a major medical center. This platform has the potential to substantially enhance the quality of pediatric care across a wide range of scenarios, not only in advanced hospital settings but also in regular homes and clinics of lower- and middle-income countries. |
Tuesday, March 15, 2022 3:36PM - 3:48PM |
K31.00004: Low Fluence, High Sensitivity Optical Pump/Supercontinuum Probe Spectroscopy Wesley E Deeg, Manita Rai, Darius H Torchinsky Obtaining spectroscopic information from ultrafast time-resolved measurements either requires discrete scanning of the probe wavelength and repeated measurement, or the use of high fluence laser systems and supercontinuum generation that must be measured with a CCD camera. While this latter approach can yield a wealth of information across a wide swath of photon energies, the required CCD cameras can be expensive while not providing as sensitive measurement as available with lock-in detection. Here, we describe a novel optical pump-supercontinuum probe apparatus based on a nonlinear photonic bandgap fiber and a digital mirror device that allows for lock-in detection of the time resolved change in reflectivity across a spectrum that spans from ~500 - 800 nm with the possibility to reach wavelengths as long as 1600 nm. Notably, our device relies on a single element detector instead of CCD cameras, and since it is based on a Ti:sapphire oscillator system, it can be performed at high repetition rates and and much lower incident fluences as compared with approaches based on amplified lasers. |
Tuesday, March 15, 2022 3:48PM - 4:00PM |
K31.00005: 20GHz pulse position modulation with a low jitter Photon Number Resolving Superconducting Nanowire Single Photon Detector Andrew Mueller The emergence of high performance Superconducting Nanowire Single Photon Detectors (SNSPDs) is pivotal to the development of future quantum and photon-starved classical communication systems. These detectors achieve low jitter, high efficiency, and photon number resolution (PNR) all in a single device. We demonstrate the use of a differential readout Niobium Nitride SNSPD in a 20GHz pulse position modulation (PPM) communication protocol. The detector uses differential readout as well as impedance matching tapers for efficient coupling of energy out of the nanowire. Furthermore, the tapers induce photon number dependent distortions on the rising edge of the readout pulse. Therefore timetagging these pulses at a constant voltage convolves photon arrival time and photon number information. We demonstrate a method for measuring RF pulse slope that may be used to (1) measure photon number per optical pulse and (2) extract a low jitter photon arrival time measurement that is uncorrelated with photon number. Our photon-starved communication demonstration therefore fully exploits the lower jitter of a new SNSPD type to run at high rate, while managing its complex manifestation of photon number resolution. |
Tuesday, March 15, 2022 4:00PM - 4:12PM |
K31.00006: A ruthenium oxide thermometer for dilution refrigerators operating down to 5 mK Gabor A Csathy, Sean A Myers, Hongxi Li At the lowest temperatures achieved in dilution refrigerators, ruthenium oxide resistance thermometers often saturate and therefore lose their sensitivity. In an effort to extend the range of such temperature sensors, we built a thermometer which maintains sensitivity to 5 mK. A key component of this thermometer is an in situ radio frequency filter which is based on a modern rf absorption material. We show that the use of such a filter is only effective when it is encased in the same rf-tight enclosure as the ruthenium oxide sensor. Our design delivers an attenuation level that is necessary to mitigate the effects of parasitic heating of a fraction of pW present in our circuit. Furthermore, we show that the likely origin of this parasitic heating is the black body radiation present within the experimental space of the refrigerator. |
Tuesday, March 15, 2022 4:12PM - 4:24PM |
K31.00007: Microwave Resoant Cavity Transducer for Fluid Flow Sensing Alexander Heifetz, Sasan Bakhtiari, Eugene R Koehl, Tianyang Fang, Jafar Saniie, Anthonie Cilliers We are developing a microwave cavity-based transducer for applications in high-temperature fluid flow sensing. This sensor is a hollow metallic cylindrical cavity, which can be fabricated from stainless steel, and expected to be resilient to ionizing radiation, high temperature (above 500C) and corrosive environment of molten salt cooled and liquid sodium cooled nuclear reactors. Currently, limited options exist for flow sensing in such fluids, particularly for salts such as FLiBe (mixture of lithium fluoride and beryllium fluoride), with melting point at ambient pressure above 450C. The principle of sensing consists of making one flat wall of the cylindrical cavity flexible enough so that dynamic pressure, which is proportional to fluid velocity, will cause microscopic membrane deflection. Cavity volume change due to membrane deflection leads to a measurable shift in the resonant frequency. Membrane thickness is determined according to the constraint that maxium stress, which is on the membrane circumference, should remain an order of magnitude below material yield strength. A cylindrical resonator prototype with 0.875in diameter and 0.01in membrane thickness was fabricated from brass for microwave K-band operation. Microwave field was coupled from a waveguide through a subwavelength-size aperture on the side of the cavity. A leak-proof assembly consisting of a piping Tee with a bulkhead WR-42 microwave waveguide was developed for cavity insertion into a fluid stream. Preliminary tests were conducted in a water flow loop at room temperature and ambient pressure. Optimal response to flow sensing was observed when the cavity was excited in TE011 resonant mode. |
Tuesday, March 15, 2022 4:24PM - 4:36PM |
K31.00008: Seebeck coefficient measurements for cryogenic temperatures Liana Shpani, Nicole M Verboncoeur, Mingqi Ge, James O Sears, Adam Holic, Matthias U Liepe Minimizing thermoelectric currents in cryomodules in particle accelerators during the cooldown procedure is essential to operate superconducting radio-frequency cavities most efficiently. Determining the thermoelectric performance of materials used in accelerator cryomodules is therefore needed. The temperature-dependent Seebeck coefficient describes the electric potential that develops across a conductor in the presence of a temperature gradient and can generate electric currents. This work uses an experimental setup to measure the Seebeck coefficient at cryogenic temperatures, namely in the 10-200K range, for materials commonly used in cryomodules, such as niobium, titanium, niobium-titanium, copper, silicon bronze, and stainless steel. |
Tuesday, March 15, 2022 4:36PM - 4:48PM |
K31.00009: A Simultaneous High Temperature and High Magnetic Field Furnace for Advanced Materials Synthesis and Processing Steven Flynn, Michael E Bates, Jared C Lee, Michael R Tonks, Michael S Kesler, Michele V Manuel, Victoria M Miller, Mark W Meisel, James J Hamlin Recent work applying magnetic fields to materials synthesis and processing has demonstrated promising effects on the properties of the products. Enhanced kinetics, improved mechanical properties, shifting phase equilibria, or even highly altered quantum states have been observed following heat treatments in high magnetic fields. The underlying physical processes responsible for these effects, as well as the opportunities for materials design and discovery they offer, remain largely underexplored. A critical obstacle to developing this understanding is the lack of instrumentation which can perform a controlled experiment over a wide range of both field and temperature. Here we describe our development of a maximum 1200 °C furnace insert for a 400 MHz NMR (9.4 T), 89 mm bore magnet. Preliminary examples of field-assisted synthesis and processing experiments are also reported. |
Tuesday, March 15, 2022 4:48PM - 5:00PM |
K31.00010: Direct comparison of millikelvin primary electron thermometers and cryogenic low-pass filters Elias R Hansen, Joost van der Heijden, Merlin von Soosten, Joonas T Peltonen, Jukka P Pekola, Jonatan Kutchinsky, Ferdinand Kuemmeth With the growing quantity and increasing complexity of millikelvin quantum electronics experiments, the ability to keep the effective temperature of electrons close to the temperature provided by a dilution refrigerator becomes ever more challenging. This requires the integration of robust low-pass filters, appropriate thermal anchoring, and radiation shielding, while it also increases the demand for accurate primary electron thermometers to be directly implemented in experimental setups. Here, we present a direct comparison of two established primary electron thermometers: Coulomb blockade thermometers (CBT) based on series of tunnel junctions between metallic islands [1], and normal-metal-insulator-superconductor (NIS) junctions [2]. Their operating principles are disparate, as aluminum is used as superconductor for the NIS but as normal metal for the CBT. We characterize both types of thermometers inside cryofree dilution refrigerators down to 10 mK base temperatures, measuring electron temperatures below 30 mK. We use these electron thermometry methods to investigate the influence of several types of low-pass filtering at different stages in the dilution refrigerator. |
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