A tunable liquid lens with extended depth of focus

Abstract

A liquid tunable lens with extended depth of focus (DOF) is presented. By integrating a rotational symmetric quartic function (QF) phase plate into the liquid lens' cavity, the lens can achieve higher tolerance to the defocus aberration. The liquid lens was fabricated through a convenient and low-cost process that combined single-point diamond turning (SPDT) with soft lithography using polydimethylsiloxane (PDMS). Experimental and theoretical results are in good agreement. Both focal length tunability and extended DOF have been demonstrated with the proposed liquid lens.