Atomic vapors offer many opportunities for manipulating electromagnetic signals across a broad range of electromagnetic spectra. Here, a microwave signal with an audio frequency modulation encodes information in an optical signal by exploiting an atomic microwave-to-optical double resonance and magnetic-field coupling that is amplified by a resonant high-Q microwave cavity. Using this approach, audio signals are encoded as amplitude or frequency modulations in a GHz carrier, transmitted through a cable or over free space, demodulated through cavity-enhanced atom-microwave interactions, and, finally, optically detected to extract the original information. This atom-cavity signal transduction technique provides a powerful means by which to transfer information between microwave and optical fields, all using a relatively simple experimental setup without active electronics.
The Lindblad term is a general descriptor of relaxation processes, .