Optical knife-edge technique for nanomechanical displacement detection

We describe an optical knife-edge technique for nanomechanical displacement detection. Here, one carefully focuses a laser spot on a moving edge and monitors the reflected power as the edge is displaced sideways. To demonstrate nanomechanical displacement detection using the knife-edge technique, we have measured in-plane resonances of nanometer scale doubly clamped beams. The obtained displacement sensitivity is in the similar to 1 pm root Hz range-in close agreement with a simple analytical model. (c) 2006 American Institute of Physics.