Control of micro-cantilever using passive optical feedback for force microscopy

We demonstrate the use of bolometric force backaction in lever-based miniature Fabry–Pérot (FP) optical cavity for micro-cantilever control. In our experiment, low finesse FP microcavity is formed by polished fiber end and mass loaded micro-cantilever. We show that the dynamics of micro-cantilever can be deeply modified when photon intensity stored in the FP microcavity is sufficiently large. For blue microcavity detuning, we confirm this control mechanism can optimize the dynamics of micro-cantilever and dramatically reduce its Brownian motion amplitude without deteriorating force resolution. This effective and low-cost control method can be simply realized in most optical detection force microscopes.