VLF "Quantum Radio"

It sounds like science fiction, but researchers at the National Institute of Standards and Technology (NIST) are combining digitally-modulated magnetic signals with quantum physics to develop a communication technology capable of operating underground, underwater or in urban canyons, where standard radio signals do not propagate well. 

The ARRL Letter reports that NIST project leader Dave Howe, AD0MR, explained that the system under development would use very low frequencies and a magnetic-field sensor that relies on "the quantum properties of rubidium atoms." The technology uses variations in a signal's magnetic field as a means of modulation. Howe told the ARRL it would be "great fun" to experiment with the quantum radio in the new 2200-meter amateur band.

NIST physicist Dave Howe aligns a laser beam to pass through a tiny glass cell of rubidium atoms inside the cylindrical magnetic shield. The atoms are the heart of an atomic magnetometer demonstrated as a receiver for magnetic radio. These very low frequency (VLF) digitally modulated magnetic signals can travel farther through building materials, water, and soil than conventional communications signals at higher frequencies and, with further advances in receivers and transmitters, could improve communications and mapping indoors at long range, in urban canyons, underwater and underground. (Credit: Burrus/NIST)