A single right-angle prism was used for the optical readout of micro-electro-mechanical systems (MEMS) cantilever arrays.

The deflections of the cantilevers were measured by using the non-linear reflectivity arisen from the internal reflection.

The non-linear nature of the detection enables the self-sustained oscillation (SSO) operation of MEMS cantilevers with a simple geometry.

Simultaneous self-sustained oscillations of two cantilevers with resonant frequencies in the range 25–30 kHz was demonstrated experimentally in closed-loop.

It was shown that multiple oscillations are obtainable if the cantilever resonant frequencies are separated from each other by at least 3 dB bandwidth.