Pump Oscillator Research Articles

Single-mode squeezed-light generation and tomography with an integrated optical parametric oscillator.

Quantum optical technologies promise advances in sensing, computing, and communication. A key resource is squeezed light, where quantum noise is redistributed between optical quadratures. We introduce a monolithic, chip-scale platform that exploits the χ(2) nonlinearity of a thin-film lithium niobate (TFLN) resonator device to efficiently generate squeezed states of light. Our system integrates all essential components-except for the laser and two detectors-on a single chip with an area of one square centimeter, reducing the size, operational complexity, and power consumption associated with conventional setups. Using the balanced homodyne measurement subsystem that we implemented on the same chip, we measure a squeezing of 0.55 decibels and an anti-squeezing of 1.55 decibels. We use 20 milliwatts of input power to generate the parametric oscillator pump field by using second harmonic generation on the same chip. Our work represents a step toward compact and efficient quantum optical systems posed to leverage the rapid advances in integrated nonlinear and quantum photonics.

170 GHz quasi-optical sub-harmonic mixer with a back-to-back lenses packaging based on HDI.

The paper presents a 170 GHz quasi-optical sub-harmonic mixer with a 3D-printed back-to-back lenses packaging. The quasi-optical mixer is comprised by a pair of antiparallel GaAs Schottky diodes, a patch antenna for receiving local oscillator (LO) pump signal, a symmetric-slit patch antenna for receiving radio frequency (RF) signal, dual 3D-printed lenses and a matching network. The quasi-optical mixer with a pair of antiparallel GaAs Schottky diodes is designed on a multilayer build-up printed circuit board (PCB) utilizing commercially low-cost and high-density interconnect (HDI) technology. The LO and RF antennas are placed on the front and back of the multilayer build-up substrate, respectively, thus significantly simplifying the quasi-optical design. Furthermore, dual 3D-printed lenses placed back-to-back are proposed for LO and RF antennas radiation gain enhancement and mechanical robustness. Additionally, the buried planar reflectors in the substrate maintain effective radiation isolation between the antennas. For facilitating coupling efficiency of signal power into the Schottky diodes and signal isolation between the LO pump signal and RF signal, a compact matching network with low-loss quasi-coaxial via transition structure is integrated in the mixer circuit. The measured single-sideband conversion loss is from 11.3 to 15.4 dB in an operation range of 160 to 180 GHz. The measured radiation patterns agree well with the simulated results.

A frequency boosting technique for cold-start charge pump units

A novel frequency boosting design technique for charge pump architectures is proposed, enabling high speed performance with no additional circuitry or design complexity. The charge pump's oscillator exploits the boosted output voltage of the topology, to provide higher switching frequency to the pumping capacitors. A Dickson charge pump using native NMOS devices is designed and fabricated in XFAB 0.18-μm process, as a product vehicle. The proposed solution is theoretically analyzed and compared to the standard approach. Mathematical analysis, together with simulation results and hardware measurements confirm the validity of the proposed technique, as well as its advantages versus the standard design methodology.

Manipulating nanoliter fluid circuits on an all-glass chip by the magnetic field

Actively controlled nanoliter fluid circuits are an urgently needed technology in electronics, biomedicine, chemical synthesis, and biosensing. The difficulty lies in how to drive the microfluid in an isolated and airtight manner in glass wafer. We used a magnetic oscillator pump to realize the switching of the circulation direction and controlling the flow rate of the 10nL fluid. Results of two-dimensional numerical simulations shows that the flow field can reach a steady state and a stable flow can be obtained. The contribution of each vibration cycle to the flow rate is proportional to the frequency, decays exponentially with the viscosity, is proportional to the 4.2 power of the amplitude, and is proportional to the radius. Compared with the existing fluid technology, this technology realizes the steering and flow control of a fully enclosed magnetic control fluid circuit as small as 10nL in hard materials for the first time.

Development of an SIS Mixer-Based Low-Noise Amplifier Amenable to Josephson Oscillator Pumping

We propose a low-noise and low-power-consumption microwave amplifier using superconductor-insulator-superconductor (SIS) mixers as quasi-particle frequency up- and down-converters pumped by a Josephson array oscillator in the millimeter-wave band. A proof-of-concept study of an amplifier with two W-band waveguide mixers using Nb/Al-AlOx/Nb junctions in a cascade connection demonstrated an average gain of 6 dB and a noise temperature of 12 K from nearly DC to 5 GHz. We also designed and fabricated a Josephson array oscillator at 100 GHz, which consisted of 31 overdamped Josephson junctions placed at each half-wavelength in an Nb microstrip line. The estimated output power of the oscillator was 0.2 μW at 100 GHz, which can be increased by increasing the number of the oscillator junctions. These results suggest that the proposed SIS mixer-based amplifier is suitable for on-chip integrated circuits to be implemented in large-scale multipixel SIS receivers and quantum computers.

Sub-40 fs optical parametric oscillator beyond the gain bandwidth limit.

We report a compact and passively stable optical parametric oscillator for direct generation of sub-40 fs pulses, five times shorter than the 200 fs pump oscillator. By employing an intracavity all normal dispersion feedback fiber, we achieved low-noise and coherent broadening beyond the parametric gain bandwidth limitation. We demonstrate spectral coverage from 1.1 to 2.0 µm with excellent passive power and spectral stability below 0.1% rms and a footprint smaller than 14 × 14 cm2.

Noise and Conversion Analyses for High-T c Superconducting Harmonic Mixers: Theoretical Modeling and Experimental Verification

High- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> superconducting (HTS) harmonic mixers are attractive frontends for terahertz wireless communication and sensing applications. However, the investigation of HTS harmonic mixers has long been hindered by the lack of effective theoretical method in device modeling. This article presents a modeling approach for analyzing the noise and conversion properties of HTS harmonic mixers. By quantitively analyzing the contribution of the parasitic components to frequency conversion, a parasitics-selection based equivalent circuit model is built with the architecture complexity reduced to a six-port network. Besides, a fast hybrid-solution method that combines the single-tone current excitation and perturbation-derivation processing techniques, is developed for efficiently calculating the conversion impedance matrix for harmonic mixing. Detailed derivations are then carried out to acquire the semianalytic expressions of noise temperature and conversion gain after solving the noise correlation matrix for harmonic mixing. The presented modeling method has been verified by the fourth harmonic mixing experiments for a dual-band antenna-coupled HTS Josephson-junction mixer module. The measured and simulated results are in good agreement in terms of the noise temperature and conversion gain as well as their dependance on dc biasing, local oscillator pumping, and operating temperatures. The results have validated the effectiveness of the presented modeling method for analyzing the properties of HTS Josephson junction mixers.

Simulation of transient dose rate effect on analog phase locked loop

The transient dose rate effect (TDRE) on analog phase locked loop (PLL) is presented in this paper. New TDRE models of NMOS and PMOS are proposed through the combination of SPICE and Sentaurus TCAD, which improve a previous modeling method and especially incorporate the effects of the Length/Width ratio of transistors, resistance network of the substrate, and bias condition of contacts. The primary photocurrents in TDRE models, calculated by TCAD, are successfully fitted by double-exponential functions. Firstly, the TDRE of each PLL's sub-circuit is simulated. Then, the global effect of the PLL is simulated and the coupled relationship among sub-circuits is analyzed. Simulation results indicate that the current-based charge pump and voltage-controlled oscillator are sensitive to TDRE, and there is a significant coupled relationship between the two sub-circuits. On the contrary, the phase frequency detector shows low sensitivity to TDRE. Lastly, as two Radiation-Hardened-By-Design (RHBD) methods, using the voltage-based charge pump and using the voltage-controlled oscillator with a large drive current are proved to be effective in improving the TDRE of PLL.

Effects of syringe pump fluctuations on cell-free layer in hydrodynamic separation microfluidic devices

Syringe pumps are widely used biomedical equipment, which offer low-cost solutions to drive and control flow through microfluidic chips. However, they have been shown to transmit mechanical oscillations resulting from their stepper motors into the flow, perturbing device performance. These detrimental effects have mostly been reported on microdroplet production, but have never been reported on hydrodynamic two-phase separation, such as in microdevices making use of cell-free layer phenomena. While various mechanisms can be used to circumvent syringe pump oscillations, it is of interest to study the oscillation effects in naïve systems, which are common in research settings. Previous fluctuation studies focused on relatively low flow rates, typically below 5 ml/h, and showed a linear decay of the relative pressure fluctuations as a function of the flow rate. In this work, we have uncovered that the relative pressure fluctuations reach a plateau at higher flow rates, typically above 5 ml/h. Using a novel low-cost coded compressive rotating mirror camera, we investigated the effect of fluctuations in a hydrodynamic microfluidic separation device based on a cell-free layer concept. We demonstrated that cell-free zone width fluctuations have the same frequency and amplitude than the syringe pump-induced pressure oscillations and illustrated the subsequent degradation of particle separation. This work provides an insight into the effect of syringe pump fluctuations on microfluidic separation, which will inform the design of microfluidic systems and improve their resilience to pulsating or fluctuating flow conditions without the use of ancillary equipment.

A Flow-through Microelectrode Sensor for Monitoring in Operando Concentrations in Redox Flow Batteries

The development of next-generation redox flow batteries (RFBs) heavily relies on the advancement of new component materials (e.g., redox electrolytes, membranes/separators) that enable low-cost, high-performance, and long-duration energy storage systems.1 The efficient evaluation of candidate materials thus requires simple and robust methods for investigating the evolution of system components during operation—in particular, near real-time monitoring of the battery state-of-health would enable timely interventions that extend lifetime or prevent safety incidents. Prior work has primarily comprised the measurement of electrolyte state-of-charge,2–4 and while this can qualitatively describe the state of the redox electrolyte, knowledge of the individual active species concentrations is needed to quantitatively assess the causes of performance loss. Accordingly, we have established the use of microelectrodes for studying the ex situ decomposition of RFB active materials, showing that this technique can simultaneously describe contributions from self-discharge reactions and molecular decomposition.5 However, considering the flow disturbances (e.g., pump oscillations, irregular flow, non-uniform mixing, etc.) associated with operating RFBs, it is especially challenging to integrate microelectrodes directly into flow cells, as the steady-state current can be highly variable due to undesired advection. Here, we seek to expand the versatility of microelectrodes by leveraging and directing this flow to study redox electrolytes within an operating cell.In this presentation, we describe the integration of microelectrodes into an in-line, flow-through electrochemical cell for use as an operando diagnostic tool to measure redox species concentrations in RFBs (see Figure). The cell consists of a three-electrode assembly, with a pseudo-reference electrode, to accurately quantify species concentrations via the steady-state current obtained from the microelectrode. First, we validate the proposed working principle using multi-physics simulations, and assess the measurement protocol ex situ under quiescent and flow conditions. Using a model electroactive compound (N-(2-(2-methoxyethoxy)ethyl)phenothiazine, MEEPT) prepared at varying states of charge, voltammetry reveals that the steady-state current can be reliably measured with a platinum wire pseudo-reference electrode, which can be used in place of standard fritted reference electrodes to reduce contamination and drift. Subsequent e x situ current measurements under steady flow yield a stable current response that increases with flow rate, in general agreement with simulation results. Importantly, as long as the flow conditions remain consistent throughout testing, the current remains linear with concentration, allowing the concentration to be determined from the steady-state current using an empirical mass transfer coefficient. As a proof-of-concept, we demonstrate the use of this sensor in a symmetric, non-aqueous redox flow cell using MEEPT. Finally, and perhaps most notably, this diagnostic tool is comprised of commercial off-the-shelf components, making it a readily accessible to any laboratory studying RFBs. Acknowledgments This work was funded by the National Science Foundation (NSF) under Award Number 1805566. B.J.N. and K.M.T. gratefully acknowledge the NSF Graduate Research Fellowship Program under Grant Number 1122374. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF. References B. R. Chalamala, T. Soundappan, G. R. Fisher, M. R. Anstey, V. V. Viswanathan, and M. L. Perry, Proceedings of the IEEE, 102, 976–999 (2014).C. Stolze, J. P. Meurer, M. D. Hager, and U. S. Schubert, Chem. Mater., 31, 5363–5369 (2019).M. Skyllas-Kazacos and M. Kazacos, Journal of Power Sources, 196, 8822–8827 (2011).C. Stolze, M. D. Hager, and U. S. Schubert, Journal of Power Sources, 423, 60–67 (2019).J. A. Kowalski, A. M. Fenton, B. J. Neyhouse, and F. R. Brushett, J. Electrochem. Soc., 167, 160513 (2020). Figure 1

Design Artificial Stem Cell Nests for Stem Cell Niche in a Microfluidic Petri Dish Programmed by a Cell Phone

AbstractThis article describes a technology to transform a petri dish into a microfluidic chip with a stem cell nest for stem cell niche engineering. A permanent magnet sphere is put in a 30 mm petri dish as an oscillator pump (O‐pump). An earphone‐sized actuator outside the petri dish receives the programmed audio signal from an MP3 player or a mobile phone to drive the in‐dish O‐pump for a microflow. There are guiding walls to form a wake area for the cell nest at the dish's center. The cell nest uses the wake to create a stable, ultraslow internal microcirculation flow. The retention half‐life of nanoparticles in the cell nest is 1419.8 ± 1.3 s. By setting the microfluidic program and supplementing five drops of the culture medium outside the cell nest every 2 d, the growth rate of embryonic stem cells in the cell nest during the 8 d automatic culture appears significantly optimized. The single clone area of embryonic stem cells increases from (3.57 ± 0.52) × 105 to (11.67 ± 1.33) × 105 µm2 after 2 d of the automatic culture and advances to (53.34 ± 8.37) × 105 µm2 after 4 d.

A Highly Programmable Magnetic Micropump

AbstractA cheap, small, convenient, reliable, and durable lab‐on‐a‐chip is needed for various scenarios in practical applications. The authors hope to use the chip only after plugging in a mobile phone. An ideal micropump design is obtained by simplifying the micropump theory, reducing the micropump to 1 mm (oscillator pump, O‐pump), the external device (actuator) to 5 mm, and the power to 10 mW. This system costs ≈$10 and can work in harsh fluid environments (such as animal cell culture) for an extended period (a few months of testing). An MP3 player drives two O‐pumps by a programmable playlist. The O‐pump is a permanent magnet positive sphere in an open fluid space, which is not easy to block and rolls freely without wear. Only controlled by the magnetic field, the O‐pump avoids interference from the current, electric field, and chemical activity. The fluid is driven by a vibrating motion, in open or sealed channels, with no unique materials and no other equipment. The debris, bubbles, and fibers in the blood viscosity fluid do not affect the pump's function. The system can be applied in different scenarios, such as the automatic cultivation of stem cells or point‐of‐care devices.

Acute and Chronic Pre-Clinical Implants of the CorWave LVAD: Hydraulic, Hemocompatibility and Hemodynamic Results

The CorWave LVAD employs a unique "wave membrane" technology, inspired from the motion of aquatic animals, to generate blood flow. This low shear method of blood propulsion can be rapidly modulated to produce a physiologic pulse. The present study evaluated the hydraulic, hemodynamic and hemocompatibility performance of the device in vitro and in animal implants. The pump membrane, oscillation frequency and magnitude, and blood flow path were simulated by CFD analysis in COMSOL and refined to improve hydraulic efficiency and eliminate areas of flow stagnation. Hydraulic testing in a mock circulatory loop and hemolysis measurements in static and pulsatile conditions were then performed in vitro. Acute and chronic implants of the improved pumps were carried out in sheep. The device was successfully operated in 4 different modes: continuous or fixed (similar to rotary VADs with a constant operating point), synchronous co-pulsation and counter-pulsation, and asynchronous pulsation modes. Sensorless detection of native ventricle systole was developed using a mock circulatory loop, with performance confirmed in acute implants in sheep with induced heart failure. The pump could generate average flow rates of 6+ lpm against physiologic pressure, and instantaneous flow rates exceeding 12 LPM during pulsatile operation. Acute and chronic animal implants (up to 60+ days) demonstrated low hemolysis and an absence of significant thrombus or thromboembolic events. The first long-term chronic animal studies of the CorWave LVAD validated the hemocompatibility and hemodynamic performance of the pump. The ability to restore physiologic pulsatility by sensorless synchronization with the native heart was demonstrated in pre-clinical implants. Extensive computational simulation and bench top testing were used to optimize this unique LVAD, displaying the full flow capacity and adding physiologically relevant pulsatility without excessive shear rates.

Focus on lasers, imaging, and microscopy

Focus on lasers, imaging, and microscopy

Numerical investigations of the flow induced oscillation of a torque converter

The flow induced oscillation of a three-element torque converter was investigated numerically under various operational conditions. A two-way coupling fluid–structure interaction simulation was performed using ANSYS-Fluent along with the ANSYS Transient Structural module. The fluid pressure excitation and the dynamic structure response were investigated at various turbine/pump rotation speed ratios . The maximum pressure blade load and structural deflections were observed in the stall condition, corresponding to the highest torque transmission ratio. The pressure pulsations and structure oscillations were monitored at locations selected on the basis of time-averaged distributions. The turbine oscillations were dominated by the frequency of pump blade passing at . The stator always oscillated under impact from the upstream flow with the dominating pump shaft frequency. Both the time-averaged and instantaneous features revealed that the pump oscillations were almost independent of SR.

Markovian Dynamics of Josephson Parametric Amplification

Abstract. In this work, we derive the dynamics of the lossy DC pumped non-degenerate Josephson parametric amplifier (DCPJPA). The main element in a DCPJPA is the superconducting Josephson junction. The DC bias generates the AC Josephson current varying the nonlinear inductance of the junction. By this way the Josephson junction acts as the pump oscillator as well as the time varying reactance of the parametric amplifier. In quantum-limited amplification, losses and noise have an increased impact on the characteristics of an amplifier. We outline the classical model of the lossy DCPJPA and derive the available noise power spectral densities. A classical treatment is not capable of including properties like spontaneous emission which is mandatory in case of amplification at the quantum limit. Thus, we derive a quantum mechanical model of the lossy DCPJPA. Thermal losses are modeled by the quantum Langevin approach, by coupling the quantized system to a photon heat bath in thermodynamic equilibrium. The mode occupation in the bath follows the Bose-Einstein statistics. Based on the second quantization formalism, we derive the Heisenberg equations of motion of both resonator modes. We assume the dynamics of the system to follow the Markovian approximation, i.e. the system only depends on its actual state and is memory-free. We explicitly compute the time evolution of the contributions to the signal mode energy and give numeric examples based on different damping and coupling constants. Our analytic results show, that this model is capable of including thermal noise into the description of the DC pumped non-degenerate Josephson parametric amplifier.

Single-beam phase-modulated stimulated Raman scattering microscopy with spectrally focused detection

We present a single-beam coherent Raman microscopy method based on pump–probe, time-resolved stimulated Raman scattering (SRS) measurements with shaped probe pulses. In the single-beam method, we divide a broadband laser spectrum into three frequency bands for the pump, phase-modulated (PM) probe, and local oscillator (LO) probe pulses. Multiple low-wavenumber Raman modes are efficiently excited by an impulsive pump pulse, and a specific Raman mode can be selectively probed using temporal beam coupling between the PM and LO probe pulses via the Raman-induced refractive index modulation. To achieve both high sensitivity and a high spectral resolution, we allocate a large spectral bandwidth (164 cm−1) to two probe bands and use a new selective detection scheme based on the spectral focusing technique. By giving a strong group delay dispersion to the probes (45000 fs2), we can obtain an improved spectral resolution of down to 25 cm−1. In a proof-of-concept experiment, the intrinsic molecular-vibration contrast of sevoflurane, an inhaled anesthetic drug, is successfully visualized. This result suggests that single-beam SRS imaging with pulse shaping is a potentially powerful tool for detecting the Raman signals of small-molecule drugs in living cells and tissues.

A 185–215-GHz Subharmonic Resistive Graphene FET Integrated Mixer on Silicon

A 200-GHz integrated resistive subharmonic mixer based on a single chemical vapor deposition graphene field-effect transistor (G-FET) is demonstrated experimentally. This device has a gate length of 0.5 μm and a gate width of 2x40 μm. The G-FET channel is patterned into an array of bow-tie-shaped nanoconstrictions, resulting in the device impedance levels of ~50 Ω and the ON-OFF ratios of ≥4. The integrated mixer circuit is implemented in coplanar waveguide technology and realized on a 100-μm-thick highly resistive silicon substrate. The mixer conversion loss is measured to be 29 ± 2 dB across the 185-210-GHz band with 12.5-11.5 dBm of local oscillator (LO) pump power and >15-dB LO-RF isolation. The estimated 3-dB IF bandwidth is 15 GHz.

Limitation of Gravitational Wave Detector Niobè Sensitivity by the Frequency Tracking Noise

The gravity wave detector at the University of Western Australia was based on a bending flap of [Formula: see text] tuned near the fundamental resonant frequency of a [Formula: see text] resonant-bar of [Formula: see text] at a temperature of [Formula: see text]. The displacement of the bending flap was monitored with a [Formula: see text] superconducting re-entrant cavity transducer. The performance of the transducer is related to the development of a low noise microwave pump oscillator to drive the transducer. This work studies the influence of the frequency tracking noise of Niobè. It had a burst sensitivity of [Formula: see text] with a long term operation from 1993 to early 1998. It had the lowest observed noise temperature. Using the characteristics of the detector, NIOBÈ should had reached a much better sensitivity that the one measure. It seems that the noise introduced in the system by the frequency tracking device was not taken into account at the time of operation, this noise gives a value of [Formula: see text], what is the value that limited the detector sensitivity to the one measured at the time of operation.

An electromagnetically actuated high frequency oscillation pump

Electro-hydraulic power units integrate an electric motor and a hydraulic pump in a single machine. The common solution, consisting of a conventional rotary motor coupled to a rotary pump, is for the fractional kilowatt range neither efficient nor compact.The alternative studied in this work is a high frequency oscillation pump (HFOP): a pump with a single alternating piston that oscillates at high frequency, up to 300 Hz. In this concept, the piston is moved by a biased reluctance actuator. The limited number of moving parts of this design leads to a reduction of the friction and to an increase of the efficiency. The high frequency approach is a step towards superior power density. Typical applications are compact hand held devices, like spreaders and cutters for rescuing in car accidents, and complex machines, that require distributed compact high force actuators.This paper draws the focus to the main issues concerning the HFOP, starting from theoretical investigation over design to the experimental testing. Particular attention is given to the design optimization of a fast plate type check valve. Experimental tests with the constructed prototype confirm the benefits of the optimized design in terms of volumetric efficiency and reduction of cavitation.