Multichannel Six-Wave Mixing with Spatial Multimode and Squeezing via Atomic Coherence

Multimode properties, based on nonlinear parametric processes, have potential research value on entanglement imaging. This paper studies the spatial and frequency multimode from dressing parametric-amplified six-wave mixing (PA-SWM) process with three entangled signals. The S1 signal contains fifth-order nonlinearity, the S2 signal contains electromagnetically induced absorption and fifth-order nonlinearity, and the S3 signal contains Autler-Townes splitting (AT), second- and fifth-order nonlinearity. The frequency multimode is attributed to dressing energy level splitting in spontaneous SWM (SSWM) process. The spatial multimode is due to frequency multimode and beam splitting via Kerr nonlinearity. In the spatial domain, it finds the optimal conditions of intensity difference squeezing (IDS) and spatial imaging along with their competitive relationship. On the one hand, the light spots with single spatial mode are contributed to the maximum IDS but not conducive to entanglement imaging; on the other hand, the light spots with multiple spatial modes are instrumental in entanglement imaging but not appropriate for the IDS. This research has potential applications in squeezed light sources for quantum metrology, and correlated imaging of spatial signals.