Fig. 2
Device architecture and experimental schematic. a Scanning electron micrograph of a similar microdisk to that used in this study. The microdisk is an optical cavity which is evanescently coupled to a tapered optical fibre. The scale bar corresponds to 20 μm. b Finite-element simulations of the modeshapes of two typical mechanical modes of the microdisk (left: second-order flapping mode, right: crown mode). c The phase sensitive and thermally stabilised experimental setup used to characterise the sensor. NP nanopositioner, MD microdisk, PD photodetector, FPC fibre polarization controller, VOA variable optical attenuator, OI optical isolator, FG function generator, OSC digital oscilloscope, NA network analyser, SA spectrum analyser. d The simulated pressure participation ratio, i.e., the fraction of the total acoustic pressure acting on the mechanical structure, for a number of frequencies. The insets display the pressure distribution at 105, 281 and 421 kHz, respectively; while p/pmax is the ratio of the pressure to the pressure at the antinodes of the acoustic wave
