Resistors Enable Adaptive Optics on the Cheap

The term "adaptive optics" conjures images of complicated and expensive systems. Researchers at Delft University of Technology in the Netherlands hope to change that. In the May 1 issue of Optics Letters, they describe a deformable mirror driven with resistors that cost them less than $100 to build.

The new system, which may find use in scientific and medical applications that do not require fast response times, features 19 off-the-shelf metal-film resistors glued to the back of the 5-cm mirrored silicon wafer. A 20-channel, 8-bit digital-to-analog converter controlled the current to the resistors and, thus, their length. The system displayed a 5-s response time and suffered thermal tremors, but it offered a temporal stability of approximately λ/10 at 633 nm.