DARPA (Defence Advanced Research Projects Agency) has launched a new program that aims to improve photon detection technology to the point where individual photons can be identified.
The Fundamental Limits of Photon Detection program will call upon the expertise of quantum physicists, designers and engineers to create a fully quantum model of photon detection that combines the best features of current photon detection technology.
“The goal of the program is to determine how precisely we can spot individual photons and whether we can maximize key characteristics of photon detectors simultaneously in a single system,” said Prem Kumar, DARPA program manager.
DARPA explained that it is attempting to improve the effectiveness of current photon detection as the process of detecting light—whether with our eyes, cameras or other devices—is at the heart of a vast number of civilian and military applications.
The research agency also pointed out that the success of their current initiative could have wide-ranging implications for industries such as photography, astronomy, quantum information processing, medical imaging, microscopy and communications.
“This is a fundamental research effort, but answers to these questions could radically change light detection as we know it and vastly improve the many tools and avenues of discovery that today rely on light detection,” said Kumar.
Photons are the massless, ghostlike packets of energy that are the fundamental units of light.
The difficulty in detecting individual photons arises when light interacts with matter. Incoming light will interact with a trillion atoms simultaneously; the cloud of atoms then has to be modeled quantum mechanically to conclude with precision that a photon was actually there. Modeling at that massive scale hasn’t been possible—until recently.
“For decades we saw few significant advances in photon detection theory, but recent progress in the field of quantum information science has allowed us to model very large and complicated systems,” Kumar explained.
“Nano-fabrication techniques have come a long way. Now not only can we model, but we can fabricate devices to test those models.”
DARPA hopes that the fully quantum model under development will determine the potential success of a device that can take the best attributes from the semiconductor detectors, superconductor detectors and biological detectors that are currently being used.
“We want to know whether the basic physics of photon detection allows us, at least theoretically, to have all of the attributes we want simultaneously, or whether there are inherent tradeoffs,” Kumar said. “And if tradeoffs are necessary, what combination of these attributes can I maximize at the same time?”