Fast tunable microlens array using electroclinic effect of chiral smectic A liquid crystals

Abstract

For real-time optical applications, fast switching microlens arrays are essential. We demonstrate a new liquid crystal microlens array based on electroclinic effect of chiral smectic A liquid crystals, which achieves fast tunable and analog modulating device. The switching time of the proposed microlens array is approximately 24s, which is more than 3times faster than conventional microlens arrays with surface stabilized ferroelectric liquid crystals (SSFLCs). As the induced tilt angle in the smectic A phase is changed to the linearly increasing electric field, the focusing beam intensity of the proposed microlens array is linearly tunable with the applied electric field. The induced tilt angle for analog optical modulation is obtained around 10 at room temperature. The proposed microlens array was fabricated by adopting a flat surfaced stacked layer of liquid crystalline polymer on a concave microlens array of UV curable polymer.