Above: A 64-pixel array of superconducting nanowire single photon detectors (SNSPD) capable of counting over 1 billion photons per second with time resolution below 100 ps. The array is mounted in a chip carrier and can be efficiently coupled to a 5-meter telescope.

Superconducting Materials & Devices

Microdevices Laboratory (MDL) has been involved at the forefront of superconducting materials research for many decades. It continues still, with an immense range of applications to NASA science and technology.

The small energy gap and strong non-linearity of superconducting materials render them uniquely suited for ultra-sensitive detectors and electronics. MDL develops and deploys novel superconducting and related non-superconducting sensor technologies for application in areas such as astrophysics, optical communications, quantum computing, Earth, planetary, and cometary sciences.

Beginning in the early 1980s, cryogenic sensor research at JPL focused on superconductor-insulator-superconductor (SIS) heterodyne mixers for astrophysical applications. In collaboration with Caltech, MDL SIS millimeter- and submillimeter-wave mixer technology was deployed in terrestrial radio telescopes, balloon and airborne observatories, and the Herschel Space Observatory. Current development is aimed at cometary water observations. MDL was also an early leader in developing and deploying Hot Electron Bolometer (HEB) mixers, primarily for frequencies above 1 THz. MDL is also developing Josephson and HEB mixers based on the high-temperature superconductor MgB2 for frequencies above 1 THz and/or for operation at temperatures up to 20 K.

In parallel with these mixer developments, there has been long-term involvement with direct detectors, such as transition-edge sensors (TES). Increasingly complex focal plane arrays based on superconducting TES have been, and are being, deployed at the South Pole on several generations of radio telescopes to gather cosmic microwave background polarization measurements at millimeter wavelengths. A more recent innovation, and a potential replacement for TES devices are Thermal Kinetic Inductance Detectors (TKIDs). TKIDs are bolometers that use the thermally sensitive kinetic inductance of a superconducting film in a resonator to monitor temperature shifts from changes in loading. These detectors offer multiplexing that is extendible to large arrays.

JPL engineers are developing a flexible microwave readout system applicable to all types of kinetic inductance detectors and related sensors. It uses commercial off-the-shelf software-defined radios that generate radio frequency interrogation tones and digitized response from cryogenic cameras. The software radio streams this data by high-speed Ethernet to a desktop computer that demodulates and filters the data, accelerating demanding computations in the computer’s graphics card. This system is more flexible than a field-programmable gate array-based solution because it is programmed with conventional languages and is already facilitating the study of novel readout techniques.

Microwave kinetic inductance detectors (MKIDs) originated at Caltech and JPL and are attracting increasing interest due to the promise of larger and more sensitive detector arrays for key astrophysical and planetary science investigations. Prototype arrays have demonstrated photon noise-limited sensitivity for imaging a 300K background. In collaboration with Professor Ben Mazin’s group at UC Santa Barbara, near-infrared-optical MKIDs are also being deployed on Palomar Observatory’s 200-inch Hale telescope and 315-inch Subaru telescope in Hawaii to search for habitable exoplanets. Another ongoing development is kinetic inductance bolometers based on the high temperature superconductor, yttrium barium copper oxide. The goal of this work is to achieve low-noise operation at 50–55K to provide the basis for a passively cooled Fourier-transform infrared spectrometer for outer planet missions. Development also continues on the quantum capacitance detector which has achieved record sensitivity, making it a promising candidate for future far-infrared missions.

A microwave frequency version of the kinetic inductance traveling-wave parametric amplifier developed in MDL has demonstrated quantum-limited sensitivity over nearly an octave of bandwidth.-New designs are targeting the Ka-band for Deep Space Network applications and cosmic microwave background measurements, and the W band for application to millimeter-wave interferometers such as the Atacama Large Millimeter Array. Nonlinear superconducting transmission lines can efficiently generate harmonics of an input waveform with an efficiency approaching unity for a narrow band of > 50 percent over a bandwidth of tens of percent. This effect has been harnessed to produce highly efficient multipliers for frequencies up to ~ 1 THz using niobium titanium nitride transmission lines. This range may be extended using other superconductors. Triplers for an initial demonstration at 300 GHz (output frequency) have been designed and are currently in fabrication.

Thermopile arrays for far IR - IR imagers are an example of a non-superconducting technology that grew out of early group activity on superconducting sensors and continues to this day. Recent applications include far-infrared spectrometers for the Radiation Budget Instrument (RBI) and the planned Polar Radiant Energy in the Far Infrared Experiment (PREFIRE).

Superconducting nanowire single photon detectors (SNSPDs) provide the highest available sensor performance from ultraviolet to mid-infrared wavelengths. MDL has been a world leader in the development of this unique technology, currently holding world records for SNSPD detection efficiency, time resolution, active area, and dark counts. JPL SNSPDs are to be employed in the ground terminal of the Deep Space Optical Communication (DSOC) project in 2022.

Dr. Warren Holmes is a Principal Engineer who specializes in detectors, electronics and cryogenic engineering for flight instruments. He led the Superconducting Devices Group and now focuses on project work. He was one of the Gruber Prize recipients in 2018 for participation in the Planck mission. Currently, he leads the delivery of the detector and cryogenic electronics system for Euclid and participates in development of concepts for future cryogenic instruments.

Mid-Infrared Detectors

Superconducting Materials & Devices

Products & Processes

Superconductors for CMB

Herschel & Planck

MKIDs

OLE MKIDs

Parametric Amplifier

QCD

SIS Mixers

High T YBCO

High T Mixers

Quantum Computation

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