  Macroscopic systems subjected to injection and dissipation of energy can
exhibit complex spatiotemporal behaviors as result of dissipative
self-organization. Here, we report a one and two dimensional pattern forming
set up, which exhibits a transition from stationary patterns to spatiotemporal
chaotic textures, based on a nematic liquid crystal layer with spatially
modulated input beam and optical feedback. Using an adequate projection of
spatiotemporal diagrams, we determine the largest Lyapunov exponent. Jointly,
this exponent and Fourier transform allow us to distinguish between
spatiotemporal chaos and amplitude turbulence concepts, which are usually
merged.
