Fluid biaxial banana phases: Symmetry at work

Fluid biaxial smectics made from compounds without asymmetric carbons but n evertheless with a spontaneous polarization are now known as banana smectic s because of their molecular shape. Here we show that symmetry changes unde r parity (r --> - r) are an efficient way to summarize and differentiate th eir electro-optic properties. Typical of fluid biaxial smectics, there are also a large number of stacking options endowing them with opto-electric pr operties spanning a broad range of economically viable applications. "Value -added features" of some banana smectics include a faster electro-optic res ponse than found in liquid crystals with a helix structure, their steric pr operty allowing rotations about an axis in a layer plane without compromisi ng smectic layer stability and ambidextrous chirality.