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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Internship Experience

I started my internship in January 2022 but the research on measuring dispersion and loss of 355nm light from a silicon oxide waveguide began in August 2022 which will be the focus of this paper. The motivation of this project is to determine whether it is possible to use pulsed 355nm light in an integrated waveguide within an ion trap chip. To begin this project, light from the 355nm Coherent Paladin laser was coupled into a fiber which will be referred to as the “source fiber.” After coupling into a fiber, loss and dispersion measurements could be performed as this fiber was used to deliver light to each of the experiments which will be covered in detail in the following paragraphs.

42 ENGINEERING↗
DOE OSTI2023

Demonstration of Microwave Cavity Transducer Performance in High Temperature Fluid Flow Sensing: Development of Microwave Cavity Flow Meter for Advanced Reactor High Temperature Fluids

We are investigating a microwave resonant cavity transducer for flow sensing in the vessel of a high temperature fluid advanced reactor (AR), such as a molten salt cooled reactor (MSCR) or a sodium fast reactor (SFR). This transducer is a hollow metallic cylindrical cavity, with one of the flat walls of the cylinder flexible enough to undergo microscopic deflection due to dynamic fluid pressure. Membrane deflection leads to a shift in the microwave resonant frequency, which can be detected with a spectrum analyzer. We have performed a preliminary proof-of-principle test of flow sensing in high temperature liquid sodium in environment, which is similar to that of an advanced reactor. The liquid sodium setup consists of a cylindrical vessel with a center feed line, where a transducer inserted through the top cap of the vessel measures velocity of the impinging liquid jet. For this test, we have developed a cylindrical resonator, which was machined from stainless steel 316 and electroplated with silver on the interior surfaces. Outer diameter of the cylindrical cavity is approximately 3cm, and the thin wall is approximately 200µm thick. We have also developed and insertion probe consisting of a 50cm WR-42 brass waveguide enclosed in a protective SS316 tube. The cavity was excited through a WR-42 waveguide through a subwavelength hole on the side of the wall of the cylinder in the TE 011 mode with resonant frequency f ≈ 17.8GHz. As a calibration experiment, we have assembled a water vessel with a center feed, and with dimensions similar to those of the liquid sodium setup. Frequency shift of the cavity spectral response was obtained at room temperature and ambient pressure by gradually increasing water flow rate from 0 to 25GPM (gallons per minute). Corresponding monotonic increase of resonant frequency by several hundred KHz was observed. Next, a sodium flow rate sensing study was performed in a liquid sodium vessel at 340° C temperature and ambient pressure. The flow rate was changed by varying sodium pump power, and a frequency shift of several hundred KHz was observed.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2023

Coherent Wavelength Switched Co-Packaged Optics to Disrupt Datacenters/HPC (AKA "QRock") (Final Report)

This project resulted in multiple first-of-a-kind demonstrations, including two generations of transmitters, a receiver, and a complete coherent link. The transmitter architecture, based on EAMs to generate QPSK modulation was first demonstrated in InP, which has limitations for scaling up to chips with multiple channels for full WDM architectures, and implementing the densities and level of integration needed to implement co-packaging with electronics. Our work resulted in the first demonstration of this architecture on a Si platform compatible with copackaging, and our working prototypes illustrated the potential of the approach. The link demonstration was also the first coherent optical link realized in a multi-micron waveguide platform. For the transmitters, integrating efficient III-V EAM devices into the large waveguide Si platform simultaneously enables significant reduction in driver power consumption while minimizing optical losses in routing and fiber coupling. On the receiver side, optical coupling and propagation losses are also minimized in the multi-micron platform, reducing required laser optical power which improves link energy efficiency. The measurement results presented in the final report demonstrate that we achieved the speed objectives for the program (112Gb/s: 56Gbaud QPSK), albeit at a higher BER than targeted. The report provides assessments of the low-powercoherent link architecture and associated components developed under the program from both technological and commercial viewpoints.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Development of INL Ultrasonic Thermometer

This document summarizes the development at Idaho National Laboratory of an ultrasonic thermometer. The ultrasonic thermometer is a temperature sensor capable of multi-point measurements at very high temperatures with a high level of radiation tolerance. All of the components of the ultrasonic thermometer have been improved over the course of this work. The base technology, a magnetosrictive transducer, has been shown to be highly radiation tolerant. The solenoidal coil used in the transducer has been redesigned to operate at higher frequencies that previously possible. Materials used for the acoustic waveguide (the sensing portion of the device) have been tested and ideal candidates identified. Finally, a solution to the sticking issue (diffusion bonding between the waveguide and a protective sheath) has been developed and tested.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

SIREN: Scaling Ion-Traps by REquiring iNnovative Heterogenous Integration

The SIREN (Scaling Ion Traps by Requiring iNnovative heterogenous integration) project explores the feasibility of heterogeneous integration (HI) as a transformative approach to scaling ion traps, a critical technology for advancing quantum computers and atomic clocks. Traditional ion trap architectures face significant challenges in scalability due to limitations in optical access, fabrication techniques, and material constraints. SIREN addresses these challenges by leveraging HI, which combines different materials and fabrication processes to create more complex and efficient ion trap structures. HI integrated structures can be manufactured without compromising the process to maintain compatibility to ion traps. This project focuses on integrating a separately fabricated waveguide with a fully functional ion trap. The respective alignment between the pieces needs to be accurate to less than 2 µm to ensure that the light from the waveguide can overlap with the trapping region. The fine alignment must also be maintained through an ultra-high vacuum bake, a critical step in preparing an ion trap experiment. The project's outcomes suggest that heterogeneous integration is a promising pathway for overcoming current scalability barriers, paving the way for the next generation of quantum technologies. SIREN's findings contribute significantly to the field, offering a scalable solution that could accelerate the development of practical quantum computers and highly accurate atomic clocks.

42 ENGINEERING↗
DOE OSTI2025

Ion Traps and Packaging for Heterogenous Integration - Chimera

Microfabricated surface ion traps and silicon-based photonics are critical technologies for scaling quantum systems. Current ion trap architectures face scalability and integration challenges due to limitations in optical access, fabrication techniques, and material compatibility. State-of-the-art quantum computers and atomic clocks are investigating monolithic integration, which necessitates custom traps for each ion species and has not overcome the integration hurdles presented by merging these technologies. The Chimera (Ion Traps and Packaging for Heterogeneous Integration) project proposes a novel approach utilizing heterogeneous integration (HI) of ion traps and photonic circuits. This separation of components allows for flexibility in ion trap design and reduces fabrication compromises. The Chimera project specifically designed an ion trap to interface vertically with a separately fabricated waveguide chip and demonstrates the first steps to integrating them at the packaging level. The ion trap features a large area of removed silicon, allowing the photonics chip outputs closer to the ion trap, improving alignment and packaging processes. The alignment must be accurate to < 1 µm to ensure that the light from the waveguide can overlap with the trapping region. This fine alignment must also be maintained through an ultra-high vacuum bake, a critical step in preparing an ion trap experiment. By combining separate chips, we demonstrate a new path for scaling trapped ion technology that is less reliant on monolithic integration. We successfully fabricated a trap with a large area of oxide removed, resulting in a region thinned to about 40 µm, a key milestone toward successful integration.

42 ENGINEERING↗
DOE OSTI2021

Optical Biosensor Platforms Display Varying Sensitivity for the Direct Detection of Influenza RNA

Detection methods that do not require nucleic acid amplification are advantageous for viral diagnostics due to their rapid results. These platforms could provide information for both accurate diagnoses and pandemic surveillance. Influenza virus is prone to pandemic-inducing genetic mutations, so there is a need to apply these detection platforms to influenza diagnostics. Here, we analyzed the Fast Evaluation of Viral Emerging Risks (FEVER) pipeline on ultrasensitive detection platforms, including a waveguide-based optical biosensor and a flow cytometry bead-based assay. The pipeline was also evaluated in silico for sequence coverage in comparison to the U.S. Centers for Disease Control and Prevention’s (CDC) influenza A and B diagnostic assays. The influenza FEVER probe design had a higher tolerance for mismatched bases than the CDC’s probes, and the FEVER probes altogether had a higher detection rate for influenza isolate sequences from GenBank. When formatted for use as molecular beacons, the FEVER probes detected influenza RNA as low as 50 nM on the waveguide-based optical biosensor and 1 nM on the flow cytometer. In addition to molecular beacons, which have an inherently high background signal we also developed an exonuclease selection method that could detect 500 pM of RNA. The combination of high-coverage probes developed using the FEVER pipeline coupled with ultrasensitive optical biosensors is a promising approach for future influenza diagnostic and biosurveillance applications.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Thermal Frequency Drift of 3D Printed Microwave Components

Fabrication of microwave slot array antennas and waveguide bandpass and notch filters using 3D printing has significant advantages in terms of speed and cost even for parts with high mechanical complexity. One disadvantage of Stereolithography (SLA) 3D printed, copper plated microwave components is that some SLA resins have a high Coefficient of Thermal Expansion (CTE), quoted in micrometers per meter per degree or 10 -6 per degree. Compared to typically used metals such as aluminum (CTE 24 × 10 -6 ·K -1 ) and copper (CTE 17 × 10 -6 ·K -1 ), SLA resin can have CTE above 100 × 10 -6 ·K -1 . Resonant structures experience significant frequency drift with temperature changes on the order of 10–50 °C. The issue of 3D printed microwave structures changing frequency characteristics significantly with temperature shift has not been addressed or reviewed in current literature. We measured and simulated the effect of temperature change on a slot array, cavity notch filters, and post loaded waveguide bandpass filters. We tested several types of SLA resin, different plating techniques, and also Direct Metal Laser Sintering (DMLS) and Binder Infusion metal 3D printing. Performance as a function of temperature is presented for these alternatives.

three-dimensional printing↗
DOE OSTI2024

Spindown of Pulsars Interacting with Companion Winds: The Impact of Magnetospheric Compression

Pulsars in binary systems with strong companion winds can have the magnetopause separating their magnetosphere from the wind located well within their light cylinder. This bow-like enclosure effectively creates a waveguide that confines the pulsar's electromagnetic fields and can significantly alter its spindown. In this paper, we study the spindown of compressed pulsar magnetospheres in such systems. We parameterize the confinement as the ratio between the equatorial position of the magnetopause (or standoff distance) R m and the pulsar's light cylinder R LC . Using particle-in-cell simulations, we quantify the pulsar spindown for a range of compressions, R m /R LC = 1/3–1, and inclination angles, χ = 0°...90°, between magnetic and rotation axes. Our strongly confined models (R m /R LC = 1/3) show two distinct limits. For χ = 0°, the spindown of a compressed pulsar magnetosphere is enhanced by approximately a factor of three compared to an isolated pulsar due to the increased number of open magnetic field lines. Conversely, for χ = 90°, the compressed pulsar spins down at less than 40% of the rate of an isolated reference pulsar due to the mismatch between the pulsar wind stripe wavelength and the waveguide size. We apply our analysis to the 2.77 s oblique rotator (χ = 60°) in the double-pulsar system PSR J0737-3039. With the numerically derived spindown estimate, we constrain its surface magnetic field to B* ≈ (7.3 ± 0.2) × 10 11 G. We discuss the time modulation of its period derivative, the effects of compression on its braking index, and implications for the radio eclipse in PSR J0737-3039.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Dielectric Resonator Design for Low Power and Low Temperature Microwave Plasma

Waveguide-based microwave plasmas generally operate at high temperatures (2000 - 6000K)[1], making it difficult to directly interface solid materials with the plasma without significant thermal damage. Dielectric microwave resonators (DMRs), long studied for wave-based manipulation of electromagnetic radiation for telecom and optics, can focus radiation to extremely small mode volumes, creating intense localized fields with low-power input.[2] This phenomenon can be used for applications ranging from efficient plasma electronics to near-ambient plasma-materials interactions. Such DMR-based plasmas have been demonstrated a handful of times in the literature, but the majority of research towards this utilize the lowest frequency resonance mode.[3], [4], [5] By carefully controlling the geometry of cylindrical resonators, a variety of electromagnetic modes can be excited. In this work, COMSOL Multiphysics simulations are used to study the electric field enhancement and absorption properties of CaTiO3 DMRs as a function of geometry and excitation frequency. Whereas previous studies have utilized the HEM111 resonance frequency to drive low power plasma excitation, we find that higher order resonance frequencies are more effective at field enhancement and result in less power loss within the dielectric material, hence less wasted heating. The effectiveness of these modes is also geometry dependent and can be computationally optimized for plasma generation. Complementing these computational efforts, we demonstrate a new closed-system reactor design built in a WR-650 waveguide and experimentally demonstrate the formation of atmospheric argon microwave plasma using < 30 W input power on DMR dimers. We observe a shifting resonance frequency as the DMRs heat in response to microwave excitation and develop a Python-based lock-in mechanism to effectively track the DMR resonance over time, leading to stable plasma operation. We use infrared thermal imaging to monitor the temperature of the DMR dimers and surrounding quartz chamber, demonstrating thermal temperatures < 60 degreesC. Finally, we utilize optical emission spectroscopy (OES) to probe the plasma properties as a function of the resonance mode.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

OLED with minimal plasmonic losses

A top-emitting organic light emitting device (OLED) that comprises: a substrate having an inward side and an outward side; an OLED body that includes a transparent bottom electrode proximate to the inward side of the substrate, an organic emitting layer, and a transparent top electrode in that order; a non-metallic, diffuse reflective layer with a roughened top surface proximate to and facing the bottom transparent electrode; and a high refractive index waveguide layer. The diffuse reflective layer is positioned between the inward side of the substrate and the OLED body, and the waveguide layer is positioned between the diffuse layer and the bottom transparent electrode.

42 ENGINEERING↗
DOE OSTI2020

Double-layer graphene optical modulators and methods of fabrication thereof

This disclosure provides systems, methods, and apparatus related to optical modulators. In one aspect, a device includes a substrate, a first electrically insulating material disposed over the substrate, a first graphene layer and a second graphene layer disposed in the first electrically insulating material and being separated by the first electrically insulating material, and a waveguide disposed on the first electrically insulating material. At least a portion of the second graphene layer overlays at least a portion of the first graphene layer. The waveguide overlays both the first graphene layer and the second graphene layer.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Electroabsorption optical modulator

An electroabsorption modulator that operates based on electroabsorption of a surface plasmon polariton mode is improved by various structural changes and/or selection of different materials. For example, at least a portion of the waveguide may be made to be conductive, e.g., by doping. Also, layers that make up the modulator structure may be placed along sides of waveguides in addition to or instead of simply on the top thereof. High permittivity gate dielectric materials may be employed. Also, materials other than ITO may be employed as a transparent conductor. Such an improved plasmonic electroabsorption modulator can be fabricated using standard semiconductor processing techniques and may be integrated with standard photonic integrated circuits, including silicon photonics and compound semiconductor-based platforms. Advantageously, high-speed, low-voltage operation over a wide spectrum of wavelengths may be achieved.

Wood, Michael↗
DOE OSTI2021

Fiber attach enabled wafer level fanout

A package assembly includes a silicon photonics chip having an optical waveguide exposed at a first side of the chip and an optical fiber coupling region formed along the first side of the chip. The package assembly includes a mold compound structure formed to extend around second, third, and fourth sides of the chip. The mold compound structure has a vertical thickness substantially equal to a vertical thickness of the chip. The package assembly includes a redistribution layer formed over the chip and over a portion of the mold compound structure. The redistribution layer includes electrically conductive interconnect structures to provide fanout of electrical contacts on the chip to corresponding electrical contacts on the redistribution layer. The redistribution layer is formed to leave the optical fiber coupling region exposed. An optical fiber is connected to the optical fiber coupling region in optical alignment with the optical waveguide within the chip.

Ardalan, Shahab↗
DOE OSTI2021

Colorless luminescent solar concentrators using colloidal semiconductor nanocrystals

Disclosed herein are embodiments of a composition comprising a polymer or sol-gel and one or more nanocrystals. The composition is useful as a luminescent solar concentrator. The nanocrystals are dispersed in the polymer or sol-gel matrix so as to reduce or substantially prevent nanocrystal-to-nanocrystal energy transfer and a subsequent reduction in the emission efficiency of the composition. In some embodiments, the polymer matrix comprises an acrylate polymer. Also disclosed herein is a method for making the composition. Devices comprising the composition are disclosed. In some cases the polymer is the waveguide, in others the polymer is applied as a coating on a waveguide. In some examples, the device is a window.

McDaniel, Hunter↗
DOE OSTI2022

All solid hybrid arrow fiber

An all solid hybrid waveguiding structure provides large mode area, acceptable losses of the desired core mode and very high losses of the undesired next higher order mode in the core. Embodiments of the waveguide include a hybrid of low index barriers providing confinement by total internal reflection, and further include high index rings that support guided modes only at effective indices different from that of the desired core mode.

Pax, Paul H.↗
DOE OSTI2023

Compact Multicell Superconducting Crab Cavity for ILC

We propose a novel design of a crab cavity (CC) for the ILC project with low parasitic High Order Modes (HOM) losses and preserving the beam emittance, which is critical for operation with high beam current intensity. Multiple electrodes immersed in the hollow waveguide form a trapped-mode resonator. The transverse components of the electromagnetic field of the trapped dipole mode induce a transverse kick and efficiently deflect charged particles passing through the cavity. We present a scalable design of a superconducting Quasi-waveguide Multicell Resonator (QMiR) seamlessly connected with a beam vacuum chamber. The cavity is completely open at both ends, which significantly reduces the maximum loaded quality factor of the higher order modes (HOM), avoids complex HOM couplers, and thus simplifies the mechanical design of the cavity. The same port is used to feed RF power to the operating mode and to extract the same order modes (SOM). Finally, we estimate the expected cryogenic losses, HOM impedance limits, RF input power required, and frequency tuning for a QMiR cavity designed to operate at 2.6 GHz.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Integrated silicon optical amplifier with reduced residual pump

An optical amplifier device employing a Mach-Zehnder Interferometer (MZI) that reduces the amount of residual pump power in the optical output of the amplifier is disclosed. The MZI amplifier employs two geometrically linear optical amplifier arms or two multi-spatial-mode racetrack optical amplifiers to amplify a signal with a pumping beam, with the signal output port having extremely low levels of residual pump power. The MZI optical amplifier is a silicon photonic integrated circuit, with all optical amplifiers, couplers, phase shifters, and optical attenuators formed of silicon photonic integrated circuit elements. The MZI optical amplifier may include one, two, or three MZI stages, and multiple MZI optical amplifiers may be used in parallel or sequentially to achieve higher overall signal gain or power. The MZI optical amplifier may employ Brillouin-scattering-based amplifiers, Raman-based integrated waveguide optical amplifiers, or Erbium-doped integrated waveguide optical amplifiers.

Lentine, Anthony L.↗