Abstract
We have studied the vibration analysis of ferroelectfic and antiferroelectric liquid crystal (FLC and AFLC) freely suspended films (FSF) by measuring the reflected laser beam from a FSF surface. Upon the application of AC electric field parallel to FSF, the vibration spectrum has generally contained a second harmonic component of the applied frequency. In the case of FLC-FSF, however, many other components also appeared in the FFT spectra of the reflected light. In addition the vibration in the SmC^* phase has markedly higher intensity compared with that in other phases. On the other hand, AFLC-FSF has shown only a second-hamonic component like a non-ferroelectric FSF in low electric field. In high electric filed enough to cause antiferroelectric-ferroelectric transition, however, fundamental and higher other components of the spectrum appear in the same manner as FLC-FSF. These complicated characteristics observed in ferroelectric phase might be attributed to the contribution of TSM.
