ECE’s Rajveer Nehra Obtains DARPA Award to Construct Next-generation, Quantum-enhanced, Detection Systems on a Nanophotonic Chip

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Nanophotonic chip developed by Nehra's team at UMass Amherst

Rajveer Nehra – an assistant professor in the UMass Amherst Electrical and Computer Engineering (ECE) Department and an adjunct in both the Department of Physics and the Manning College of Information and Computer Sciences – is the principal investigator on a three-year, $3,438,170 award from the Defense Advanced Research Projects Agency (DARPA). The grant will support collaboration among five institutions, including DARPA, to develop quantum-enhanced, field-deployable, drop-in detectors for applications in fundamental sciences and photonics-based quantum technologies.   

Nehra explains that low-noise, broadband, optical detectors are crucial for advancing emerging photonics technologies and fundamental sciences. In conventional classical detectors, the signal-to-noise ratio is typically improved by increasing laser power to enhance signal strength. However, these detectors are fundamentally constrained by the “quantum shot-noise limit” (SNL), and higher laser power can lead to photodamage or instabilities caused by radiation pressure, compromising measurement quality.

Nehra says that “Specially engineered quantum states of light, such as squeezed states with reduced or “squeezed” noise, have been shown to enable measurements beyond the SNL and serve as a key resource in quantum-information processing and sensing applications.” 

Such detection techniques have demonstrated quantum advantages in imaging, spectroscopy, navigation, sensing, and metrology applications, including the Laser Interferometer Gravitational-wave Observatory. However, their use has been mostly limited to discrete, bulky, table-top setups. 

DARPA’s INtensity-Squeezed Photonic Integration for Revolution Detectors program from the Microsystems Technology Office is seeking “innovative proposals to develop compact, ultralow-noise, optical detectors that employ squeezed-light-measurement techniques to advance precision optical sensing.” Nehra’s collaborative DARPA award answers this solicitation.

As Nehra explains, “Our goal is to develop robust detection systems with low size, weight, and power consumption by integrating squeezed-light sources, programmable interferometers, and high-quantum-efficiency photodetectors on a single nanophotonic chip. Drawing inspiration from very-large-scale integration in electronics, nanophotonics combines numerous components on a chip for building scalable and dense photonic circuits to harness the full potential of photonic quantum technologies.” 

Nehra will collaborate with Professor Andreas Beling from the Department of Electrical and Computer Engineering at the University of Virginia, Professor Sasan Fathpour of the College of Optics and Photonics at the University of Central Florida, and Professor Gregory Kanter from the Department of Electrical Engineering and Computer Science at Northwestern University.

In response to the DARPA program, as Nehra states, “Our objective is to transition advanced quantum-measurement techniques from controlled laboratory settings to practical, general-purpose, detector components. These detectors will seamlessly integrate into various optical systems with bioimaging, microscopy, computing, and telecommunications applications.” 

Nehra leads the Quantum Information Systems Lab at UMass Amherst, focused on developing scalable quantum technologies operable at room temperature, with applications in quantum computing, all-optical quantum networks, quantum-enhanced sensing, and metrology. (December 2024)