Theoretical and experimental investigation of optical excitation of nano oscillators

In the present work we report on theoretical and experimental investigation of optical resonant excitation of nano cantilevers fabricated from silicon nitride and mono-crystalline silicon layers deposited on top of a sacrificial silicon dioxide layer. The thermal energy impinged into the structure was produced by a laser beam focused at the substrate and not at the structure itself. Steady-periodic axisymmetric thermal problem for a multilayered structure heated with a modulated laser was treated analytically using an integral transform technique and verified by finite element analysis which was implemented also for the solution of steady-periodic and transient thermoelastic problems. A transfer function relating the laser source parameters to the NEMS structure response was constructed and influence of various parameters on the nanoelectromechanical structure NEMS response was investigated. Results of analysis backed by experiments indicate that the dominant actuation mechanism in the case of laser spot located in proximity of the structure was primarily thermal.