Behavior of the cholesteric liquid-crystal Fabry-Perot cavity in the Bragg reflection band

In this Letter, we investigate the behavior of the cholesteric liquid-crystal Fabry-Perot cavity in the spectral range of the Bragg reflection band. We show that in this region the 2 x 2-Jones-matrix calculation gives a false predication. However, by the use of the 4 x rt-matrix method, interesting features are revealed in the resonance spectra. The resonance spectra split when lambda similar to (n) over bar P. Our experiments confirm this phenomenon. The experimental results show that the splitting occurs in a steplike fashion. This can be explained by the quantization of the pitch that occurs due to the fixed boundary conditions.