Set of two orthogonal adaptive cylindrical lenses in a monolith elastomer device

Lin Pang,Uriel Levy,Yeshaiahu Fainman,Kyle Campbell,Alex Groisman

doi:10.1364/opex.13.009003

Abstract

A microfluidic device that operates as a set of two adaptive cylindrical lenses focusing light along two orthogonal axes is designed, fabricated and characterized. The device is made out of a silicon elastomer, polydimethylsiloxane, using soft lithography, and consists of a few chambers separated by flexible membranes and filled with liquids of different refractive indices. The cylindrical lenses can be both converging and diverging; their focal lengths are varied independently and continuously adjusted between -40 and 23 mm by setting pressure in the chambers. Applications of the device to shaping of a laser beam, imaging and optical signal processing are demonstrated.

Highlights

Adaptive optical elements are of great importance for various imaging and information processing systems, providing a “knob” for dynamic focusing, scanning and correcting aberrations
The non-zero value of ΔP0 is probably due to some non-uniformity in thickness or residual curvature of the microfabricated PDMS
We designed, fabricated and characterized a microfluidic device that operates as a set of two adaptive cylindrical lenses, which focus light along two orthogonal axes (x and y)

Summary

Introduction

Adaptive optical elements are of great importance for various imaging and information processing systems, providing a “knob” for dynamic focusing, scanning and correcting aberrations. That creates, depending on the sign of the gauge pressure, a convex or concave interface between the liquid and the atmosphere air and a converging or diverging lens, respectively This design is based on a fast and simple fabrication protocol [9,10,11,12], and it allows constructing adaptive lenses with diameters from 200 μm to 20 mm and numerical apertures reaching 0.3 at highest pressures [10, 12]. Modulation of the wave front of light occurs at the interface between the two liquids and is proportional to difference between their refractive indices and to the curvature of the membrane, which is controlled by difference in pressure between the two chambers The both chambers always remain positively pressurized with respect to the atmosphere that prevents appearance of gas bubbles. Placement of the flexible membrane in the interior of the lens makes the device more robust and less vulnerable

Concept of operation

Fabrication

Filling the device and controlling the pressure

Results and discussion

Summary