Structural Measurements On The Liquid Crystal Analog Of The Abrikosov Phase

High resolution x-ray and optical studies were performed on oriented samples of the recently discovered smectic-A* phase. We confirm that this phase exhibits smectic-A layers as well as a macroscopic helical structure with the helical axis parallel to the layer planes. Furthermore, we demonstrate that the observed scattering can be explained by a cylindrical structure factor that is a delta -function in the radial direction and a Gaussian in the transverse direction as predicted by Renn and Lubensky for the "Twist Grain Boundary" phase, a liquid crystal analog of the Abrikosov phase.