Image analysis for the destabilization process of the petal pattern in a liquidcrystal light valve with rotational optical feedback

摘要

The destabilization process from the static petal pattern to the fluctuating petal pattern in a liquid crystallight valve with optical rotational feedback is investigated experimentally. When a spatial rotation ofπ/6 is imposed on the feedback, the six-fold static petal pattern appears. At a threshold voltage of thebifurcation, rotationally propagating patches arise on the petals. With the increase of applied voltage, themotion of the patches becomes irregular and fluctuations of the pattern develop. By measuring the timecorrelation function for the spatial wave numbers along the azimuthal direction in polar coordinates, it isfound that a half of the fundamental spatial mode relevant to the six-fold petal pattern plays an importantrole in the bifurcation process. The development of fluctuations is also analyzed by the Karhunen-Loêvedecomposition in detail.