Mechanical elements with dimensions in the nanometer range, at least in one direction, have been successfully employed as sensors in various devices. Their mechanical properties must be known with maximum precision in order to quantify the sensor response to external excitation. This often poses a significant challenge due to the mechanical fragility of the sensor elements. Here we present a measurement of the mechanical response of a 100 nm thick silicon nitride membrane. The external excitation force is provided by a laser beam modulated in amplitude, while the displacement of the membrane is measured by a Michelson interferometer with a homodyne readout.
