MIT Researchers Create a Sensor Capable of Detecting Any EM Frequency, Using a Quantum Mixer

A team of researchers at the Massachusetts Institute of Technology (MIT) have developed a sensor that they claim is capable of detecting electromagnetic signals of any frequency — using what they describe as a "quantum mixer."

High-precision electromagnetic sensors are tuned to a particular frequency range, and while quantum sensors have proven capable of high-precision measurements they've done little to change that fundamental truth. The device designed by the MIT team, however, flips things on its head by offering a means of sensing signals of arbitrary frequency in a single sensor — by taking the incoming signal and mixing it.

Dubbed a quantum mixer, the sensing technique works by injecting a second frequency alongside the signal to be studied using microwave beams. As the two signals interact, the field's frequency is shifted to the differential between the two signals — allowing frequency to be adjusted to whatever frequency for which the underlying sensor is tuned.

To prove the concept, the team took a 150MHz signal and fed it through the quantum mixer before feeding the output into a qubit-based sensor tuned to 2.2GHz — far above the signal's true frequency, to which the sensor would ordinarily be entirely deaf. Once passed through the mixer and adjusted, though, the signal was picked up perfectly with no other modification to the qubit sensor.

"The same principle can be also applied to any kind of sensors or quantum devices," claims Guoqing Wang, MIT professor and first author of the study — with suggestions that the system could be built as a self-contained unit, packing both the sensor and the quantum mixer in a single device. The team is also working on using the technique to alter multiple frequencies at once, removing the need to home-in on a specific frequency.

The team's work has been published under open-access terms in the journal Physical Review X.