Fig. 2: Experimental liquid crystal light valve (LCLV) with reciprocal and nonreciprocal optical feedback.
From: Nonlinear wave propagation in a bistable optical chain with nonreciprocal coupling
a Experimental scheme of the optical valve. He-Ne Laser accounts for a Helium-Neon laser light source. O is an optical objective, SLM is a spatial light modulator, M is a mirror, PBS corresponds to a polarizer beam splitter, V0 is the voltage applied to the LCLV, BS is a beam splitter, L stands for lens, FB is a high resolution optical fibre bundle, and CMOS accounts for a Complementary Metal-Oxide-Semiconductor camera. b A bifurcation diagram is obtained for a single light cell driven by the laser applied to the optical valve, as the voltage V0 applied to the valve is varied. The vertical axis represents the total intensity measured in the camera in arbitrary units. The insets are the respective snapshots taken with the camera. The dashed circles account for the illuminated areas. The red and green triangles show the sweep with the voltage down and up, respectively. The bistability region is highlighted with vertical dashed lines. c Schematic illustration of how nonreciprocal optical feedback is generated. α accounts for the shift of the optical fibre bundle. The scale bar indicates the cell size. The panels d and e account for the temporal evolution of the intensity profiles from the optical chain system. Panels d1 and e1 in the green region account for the initial state profile. Panels d2 and e2 in the cyan region account for the final state profile in the intermediate line of the bistable chain with reciprocal and non-reciprocal coupling, respectively. The optical nonreciprocal feedback in the LCLV (α ≠ 0) is depicted with the displacement between the squares at the top of these panels.
