Liquid crystals are a unique medium for sensing small structural changes in their environment. Cholesteric liquid crystals respond to these forces by changing their pitch. A photochromic dopant in a cholesteric liquid crystal was used to translate optical input to observable pitch change. The change is reversible solely by action of light, and a cyclic mode of operation is demonstrated. The information encoded by light can be read optically without its destruction. The doped liquid crystal system does not show fatigue during the course of these experiments.