Figure 6
From: Formation and control of Turing patterns in a coherent quantum fluid
Examples of phase-matched scattering.
The scattering processes are specified by the incoming modes (red, solid circles) and outgoing modes (blue, open circles) in (transverse) momentum space. The arrows represent the modes' momenta, dashed (solid) for the incoming (outgoing) modes. The ring indicates the k-space radius at which the polariton patterns reside. (a) Linear process: basic stimulated scattering at the origin of spontaneous symmetry breaking (pattern formation). (b) Quadratic process: momentum conservation is fulfilled only for modes arranged on a hexagon; it favors stabilisation of the hexagon. (c) Cubic process: cross-saturation leading to competition between pairs of phase-cunjugate modes.
