October 11, 2018
The Harvard Gazette
Imagine trying to make sense of the cacophony of a speaker playing four songs at once, and you have some idea of the challenge faced by Hertz Fellow Jenny Schloss and Matt Turner, both Ph.D. candidates at Harvard University.
In their quest to build a tool that uses NV centers—atomic-scale impurities in diamonds—to sense the magnetic fields in everything from firing neurons to condensed-matter systems, the pair have developed a method that can simultaneously detect magnetic fields in various directions. Schloss and Turner worked with postdoc John Barry (now a research scientist at MIT Lincoln Laboratory) in the laboratory of Ronald Walsworth, a faculty member in Harvard's Center for Brain Science and the Department of Physics.
Schloss, Turner, and Barry bombarded a tiny, 4-millimeter-square wafer of diamond with four different microwave signals, each of which was tuned to monitor a specific NV orientation and dithered according to a unique frequency-modulation (FM) pattern. The researchers could then simultaneously measure how each NV orientation responded to different directions of a magnetic field—almost as if they were listening to four FM radio stations at once. The work is described in a new paper published in Physical Review Applied.