Optical characterization of a nanoscale incommensurate pitch in a new liquid-crystal phase

As a remarkable orientationally ordered soft-condensed matter system, the smectic-[Formula presented] phase exhibits an incommensurate nanoscale helical pitch of more than four smectic layers. Recent theoretical advances predict the existence of a new phase showing a helical pitch of less than four smectic layers ([Formula Presented]). By applying a novel optical technique to the study of freestanding films with increments in thickness of one smectic layer, we have measured the size of this pitch using 633 nm HeNe laser light. Our results confirm the existence of the newly predicted phase in one unique compound.