arXiv:2608.14807v1 Announce Type: new Abstract: Chiral quantum nonlinearities that arise when light interacts with quantum emitters are known to modulate only the phase but not the amplitude of scattered photons, enabling the creation of non-reciprocal photonic elements, quantum logic gates, and quantum network protocols. In this work, we show that the addition of a second photon beam drastically changes this picture, enabling both phase and amplitude modulation. Surprisingly, coherent photon transfer between the different beams enables a stronger amplitude modulation than standard symmetric interactions. This is most obvious in the coherent, three-photon amplification, which we predict peaks with a 30% efficiency in a chiral geometry, 3x the efficiency of the symmetric configuration. Our results uncover a new regime of chiral quantum optics and provide a route towards more efficient all-optical control at few-photon energies.
Multicolor nonlinear chiral quantum optics: beyond phase
arXiv:2608.14807v1 Announce Type: new Abstract: Chiral quantum nonlinearities that arise when light interacts with quantum emitters are known to modulate only the phase but not the amplitude of scattered photons, enabling the creation of non-reciprocal photonic elements, quantum logic gates, and quantum network protocols. In this work, we show that the addition of a second photon beam drastically changes this picture, enabling both phase and amplitude modulation. Surprisingly, coherent photon...