High efficiency laser photothermal excitation of microcantilever vibrations in air and liquids.

Microcantilever Actuation by Laser Induced Photoacoustic Waves

We present here a combined theoretical and experimental investigation on effective excitation of microcantilever by using photoacoustic waves. The photoacoustic waves arose from a vibrating Al foil induced by an intensity-modulated laser. We demonstrate that, superior to photothermal excitation, this new configuration avoids direct heating of the microcantilever, thus minimizing undesired therm...

Photothermal excitation for improved cantilever drive performance in tapping mode atomic force microscopy

Photothermal excitation is an alternative cantilever drive mechanism for tapping mode atomic force microscopy. It uses a power-modulated laser focused on the cantilever to directly drive its oscillation, producing cantilever tunes that match the thermal response almost perfectly. This enables quantitatively accurate AFM imaging and viscoelastic nanomechanical mapping in all environments. In add...

Photothermal excitation of microcantilevers in liquids

We report the selective excitation of the flexural modes of microcantilevers in aqueous solutions, by applying the photothermal excitation technique. The experiments show that a particular vibration mode can be efficiently excited by focusing the intensity-modulated laser beam on regions of high curvature of the vibration shape. In addition, the resulting resonant peaks in liquid appear distort...

Phototermal self-excitation of nanomechanical resonators in liquids

We report the use of the photothermal actuation for the self-excitation of a selected vibration mode of a microcantilever in liquid. The gain of the positive feedback loop is adjusted in order to obtain a negative effective damping. In this regime, the amplitude noise is squeezed due to the nonlinear saturation of the system and the phase noise is largely reduced. The microcantilever vibration ...

Case report (Technical and scientific) of transverse excitation atmospheric air laser