The University of Massachusetts Amherst
University of Massachusetts Amherst

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NSF CAREER Research Will Upgrade Cryogenic Sensors

Joseph Bardin of the Electrical and Computer Engineering Department at the University of Massachusetts Amherst has received a five-year grant of approximately $400,000 from the prestigious National Science Foundation (NSF) Faculty Early Career Development (CAREER) Program. Bardin’s research will greatly improve the cryogenic electronics used in scientific instruments, thereby enabling new and more powerful experimental tools for scientific researchers.

The research focus of Bardin’s CAREER project is to design novel broadband silicon circuits, operating at ultra-low power dissipation and cooled to cryogenic temperatures, thereby boosting the information-gathering capabilities of current, cryogenically-cooled scientific instruments by about 10 times.

Among other applications, Bardin’s work will impact terahertz heterodyne cameras and terahertz direct detection cameras used in astronomy, high-throughput free-space optical links for deep-space communications, very broadband direct-to-digital receivers, quantum computing, balloon-based instruments, and various experiments in fundamental physics. For each of these fields, Bardin’s project for developing alternative methods of amplifying weak signals at greatly reduced power consumption would be transformative.

“Our general hypothesis,” Bardin says, “is that the amount of information which can be extracted through a cryogenic sensor system can be increased by an order of magnitude through novel combinations of superconducting sensors with high-density, ultra-low-power, integrated electronics.”

The most sensitive of experimental systems rely upon cryogenically-cooled electronics. These systems allow scientists to push measurements towards the limits of fundamental physics and thus have had a profound impact on experimental science. For instance, cryogenically cooled electronic systems allow scientists to study fundamental physical phenomena through low-temperature physics experiments, to communicate with spacecraft at distant planets, to interface with quantum computers, and to probe the history and contents of the universe through radio astronomy.  

The research program is significant because it addresses currently unsolved issues in measurement, design, and system integration and is of high importance to the scientific community.

“In order to achieve the ultimate sensitivity in many sensor instruments, you have to reduce temperature to just above absolute zero,” Bardin explains. “But doing this requires a refrigerating apparatus that dissipates a significant amount of power from the system. There’s a large need in many scientific applications for instruments that image quicker, and instruments that use less power.”

The research goal of this program is to study how silicon Bipolar Complementary Metal Oxide Semiconductor(BiCMOS) technologies can be tightly integrated with ultra-sensitive superconducting sensors in order to enable an order of magnitude increase in the amount of information available from high-frequency cryogenic instruments.

“We will focus on two different applications,” explains Bardin. “Terahertz SIS focal plane receivers and superconducting nanowire single photon detector (SNSPD) cameras. These applications were selected because they will allow us to study different levels of interaction between the semiconductor and superconductor electronics, but at the same time share the requirement of extremely low power dissipation.”

As Bardin adds, “For all of the applications in both areas of research we’re looking at lowering the power consumption without giving up measurement sensitivity.”

The terahertz frequency region is of great importance to astronomers due to the large number of molecular transitions that can be observed in this frequency range. By mapping the terahertz spectrum across regions of the sky, astronomers are uniquely able to study the dynamics of molecular clouds and the interstellar medium, which in turn is critical in enriching our understanding of the physics of planet and star formation. Because the mapping speed, or the rate at which the instrument can acquire information, depends upon the number of pixels, performing spectroscopic studies over sizable swaths of the sky requires large detector arrays.

“One of our goals is to enable cameras for astronomy that can increase the resolution to about 100 times as many pixels as state-of-the-art cameras can manage now,” says Bardin. “This improvement would make it possible for astronomers to capture images over large regions of the sky that simply are not possible using current technology. The applications would include everything from studying the Big Bang to observing star formation and planet formation.”

Bardin will take a different approach in the second branch of his research, SNSPD cameras.SNSPDs are an emerging technology that allow for devices to count single photons of light, enabling highly sensitive and efficient light detection systems.The focus of this component of Bardin’s research program isto integrate a non-linear time-varying SiGe BiCMOS circuit with an SNSPD in order to demonstrate a hybrid detector that has large pulse amplitude, fast recovery time, and operates at a fraction of the power dissipation of currently used approaches. In so doing, his research will demonstrate hybrid semiconductor/superconductor systems that consume an order of magnitude less power than today’s state of the art.

In 2011 Bardin was awarded $295,000 by the Defense Advanced Research Projects Agency (DARPA) Young Faculty Award Program to do research on an electronics project entitled “Programmable Front-Ends in Advanced Technologies.” (January 2014)