We investigate the behavior of cholesteric liquid crystals (CLC's) inside a
Fabry-Perot (FP) cavity. Although FP cavities filled with various liquid c
rystals have been extensively studied, to our knowledge the behavior of CLC
-based FP cavities has not been reported. In CLC the twisted structure can
be changed because the pitch is a function of temperature. In a parallel-ru
bbed CLC FP cavity the balance between strong surface anchoring and elastic
energy yield a steplike resonance spectrum. This corresponds to the quanti
zed effective pitch that the system assumes when both surface alignments ar
e fixed. Experiment results for parallel-rubbed samples are presented and e
xplained theoretically by use of Jones matrix calculations. (C) 1999 Optica
l Society of America.