A description is given of a microlens array design, believed to be new, wit
h tunable focal length. Converging or diverging periodic refractive-index d
istribution is induced in a linear electro-optic wafer through the applicat
ion of electric field profiles on both sides of the wafer. The transparent
electrodes on both sides of the wafer are positioned such that the electrod
es on the opposite side compensate the phase delay from the electrodes on t
he front side of the wafer for a normally incident plane wave, suppressing
the intrinsic electrode diffraction for the device without applied voltage.
The original technique of the electric field calculation was developed to
analyze accurately the induced refractive index inside the wafer. Its focal
length changes from 7 mm to infinity at a 1-mu m wavelength with an extern
al voltage range of 0-100 V. (C) 2000 Optical Society of America. OCIS code
s: 120.5710, 060.5060, 110.2760, 160.2100, 130.3120.