Two-Photon Blockade in an Atom-Driven Cavity QED System

Understand

Photon blockade is a dynamical quantum-nonlinear effect that occurs in driven systems with an anharmonic excitation ladder.

• For a single atom strongly coupled to an optical cavity, we show that driving the atom gives a decisively larger optical nonlinearity than driving the cavity.
• This enhances single-photon blockade and allows for the implementation of two-photon blockade where the absorption of two photons suppresses the absorption of further photons.
• As a signature, we report on three-photon antibunching with simultaneous two-photon bunching observed in the light emitted from the cavity.