Here's some quantum optics with microwaves : http://phys.org/news/2013-05-quantum-optics-microwaves.html http://phys.org/news/2013-05-quantum-optics-microwaves.

Here's some quantum optics with microwaves : http://phys.org/news/2013-05-quantum-optics-microwaves.html http://phys.org/news/2013-05-quantum-optics-microwaves.html Even if there is no fundamental reason to believe that quantum theory would make a distinction between "microwave photons" and "optical photons", this demonstration puts this equivalence across a huge frequency range on a firm experimental footing. Moreover, the lower frequency of the microwave photons enabled a more complete characterization of the effect than has been able so far with optical photons, opening up new possibilities to characterize radiation sources. Finally, the new experiment highlights how quantum optical effects can be exploited in experiments with microwave sources, which may lead to practical applications of "microwave optics".