Recently a liquid crystal (LC) lens driven by two voltages has been proposed [1]. The new LC lens outshines its predecessors [2] in many respects. First, the focus is variable in a wide range, and the focal length simply increases with the increasing controlling voltage. Second, over the whole focus range, the lens preserves its optical quality. Third, it is easy to drive the lens with no disclination lines occurring. Forth, the LC layer is shielded by the electrodes and the properties of the lens do not be affected by electric charges outside the LC cell. Fifth, to build fast LC lenses with stacked structure of thin LC layers [3, 4], and, to build negative lenses with positive LC materials [5, 6], become possible. Here we report the building of a new LC microlens [7] with the two-voltage driving structure. One of the voltages remaining unchanged builds up a symmetrical but spatially nonuniform electric field in the LC layer. The other voltage, that is, the controlling voltage varies to adjust the gradient of the electric field, and hence the properties of the lens. The new LC microlens inherits the advantages of the new driving technique. The phase transformation and the focal length of the LC microlens are measured. The focal length increases with increasing controlling voltage and the LC microlens preserves its optical quality in the whole range of the focus.

[1] M. Ye, B. Wang and S. Sato, Appl. Opt. 43 (2004) 6407. [2] M. Ye and S. Sato, Jpn. J. Appl. Phys. 41 (2002) L571. [3] B. Wang, M. Ye, and S. Sato, Opt. Commun. 250 (2005) 266. [4] M. Ye, B. Wang, and S. Sato, IEEE Photon. Technol. Lett. 18 (2006) 505. [5] B. Wang, M. Ye, and S. Sato, Jpn. J. Appl. Phys. 44 (2005) 4979. [6] B. Wang, M. Ye, and S. Sato, IEEE Photon. Technol. Lett. 18 (2006) 79. [7] T. Nose, S. Masuda, and S. Sato, Jpn. J. Appl. Phys. 30 (1991) L2110.