| This research presents a new optical actuation scheme for MEMS devices based on the well-established fact that light possesses momentum, and hence imparts a force equal to 2W/c when reflected by a surface. Here W is the total power of the reflected light, and c is the speed of light. Radiation pressure, as it is known, is nearly insignificant for most macro scale applications, but it can be quite significant for MEMS devices. In addition, light actuation offers a new paradigm. First, intersecting light beams do not interfere, in contrast to electrical conductors, which short when they come into contact. Second, light can operate in high temperature and high radiation environments far outside the capability of solid state electronic components. A comparison between this actuation scheme and other commonly used MEMS actuation schemes is presented, emphasizing both the advantages and disadvantages of each actuation method.; Radiation pressure is demonstrated, both in air and in vacuum, by switching the state of a bi-stable MEMS device. In order to verify that radiation pressure is indeed the mechanism by which the beam is toggled, a series of experiments is performed to eliminate other possible mechanisms. The associated heat transfer model is also presented.; The experiments on radiation pressure revealed some unexpected behavior of the beam when toggled by short duration laser pulses. While long duration laser pulses at a power level slightly above the toggle threshold reliably toggled the beam every time, short duration pulses of the same power toggled the beam only about two thirds of the time. In addition, when excessively high power levels (far above the toggle threshold) were used, the device would not reliably toggle regardless of the pulse duration. In order to shed light on this unexpected behavior, a new, nonlinear dynamic analysis of the bistable beam device used in those experiments is presented. This model explains the anomalies, and extensive experimental evidence supporting the validity of the model is also presented. |
