Optical downconverter

Optical DownConverter (ODC) is an example of a non-linear optical process, in which two beams of light of different frequencies $$\omega_1$$ and $$\omega_2$$ interact, creating microwave with frequency $$\omega_3 = \omega_1 - \omega_2 $$. It is a generalization of microwave. In the latter, $$\omega_1 = \omega_2$$, both of which can be provided by a single light source. From a quantum mechanical perspective, ODC can be seen as result of differencing two photons to produce a microwave. Since the energy of a photon is given by

$$ E_\nu = \hbar\omega, $$

the frequency summing $$\omega_3 = \omega_1 - \omega_2 $$ is simply a statement that energy is conserved.

In a common ODC application, light from a tunable infrared laser is combined with light from a fixed frequency visible laser to produce a microwave created by a wave mixing process.

The ODC use milimeteric microwave cavity that include photonic crystal that provide by two signal frequency light source. The microwave is detected by the cavity antenna.