Fig. 6: Evidence of elastic Purcell-effect modification of sensor vibrational modes.
From: Coupling the thermal acoustic modes of a bubble to an optomechanical sensor
a–c Power spectral density noise plots in the vicinity of its fundamental resonance frequency for the same sensor in bulk air (black curves) and encapsulated by three different bubbles (red curves) shown in the upper-right inset microscope images (scale bars—200 μm). The black vertical arrows indicate approximate locations of the nearby cavity (bubble) eigen-frequencies in each case. The upper-left inset in (c) shows the noise spectrum near the second resonance line of the sensor, which is relatively unmodified in this case due to the lack of isolated, nearby cavity modes. d A wider range noise plot for the small bubble from part a., showing evidence of suppressed vibrational energy extending up to ~8 MHz, except for enhancement in the vicinity of a few low-order bubble acoustic modes
