Dresden 2003 – scientific programme

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HL: Halbleiterphysik

HL 42: Bauelemente I

HL 42.1: Talk

Thursday, March 27, 2003, 11:45–12:00, BEY/118

Light action on mechanical oscillators — •Constanze Höhberger, Markus Vogel, Christine Meyer, Heribert Lorenz, and Khaled Karrai — Center for NanoScience, LMU München, Geschwister-Scholl-Platz 1, 80539 München

Since the introduction of atomic force microscopy this technique was refined such that it is possible to detect single electrons or to pull on single molecules. Nonetheless it is still desirable to make force detection even more sensitive for a broad range of applications. This can be achieved for example by fabricating very soft AFM cantilevers. However, these cantilevers become difficult to handle.

We succeded in optically tuning the mechanical rigidity of cantilevers with initial spring constants of about 0.008 N/m. Using the gold coated back side of the cantilever as one mirror of a Fabry-Pérot microcavity it is possible to change its spring constant in a controlled way due to photon pressure or other light-induced force gradients.

Here we present measurements of the shift in the resonance frequency of the lever in proportion with its spring constant. The behaviour can be understood and modelled by the action of the photon gas in the system. This effect allows us to tune the mechanics of nano-opto-mechanical systems and can be used in order to detect ultra-low forces.