The advantage of a liquid crystal (LC) lens is that its focal length is electrically tunable. The operating speed of an LC lens is usually slow due to the thick LC layer used. One possible method to speed up the response of the LC directors to external electric fields is to apply an initial high voltage [1], but the switching between foci is still very slow. Recently we have reported an LC lens of three-electrode structure containing two thin LC layers [2, 3]. The thickness of the LC layers being 20 microns, and the response time can be controlled around only one second. Here we report a further study of the LC lens with stacked structure of two thin LC layers. The electric field distribution in the LC cell and the director reorientation in the spatially nonuniform electric field are numerically calculated. The properties of the lens are measured and are compared with the calculation.

[1] M. Ye and S. Sato, Mol. Cryst. Liq. Cryst. 433 (2005) 229. [2] B. Wang, M. Ye, and S. Sato, Opt. Commun. 250 (2005) 266. [3] M. Ye, B. Wang and S. Sato, Appl. Opt. 43 (2004) 6407.