Figure 2
From: Air-coupled ultrasound detection using capillary-based optical ring resonators
(a) Temporal trace detected by a DC-coupled photodetector connected to an oscilloscope. The peak-to-peak pressure at the resonator was 2.53 Pa (see Fig. S2b for the pressure calibration curve). 1.25 μs period corresponds to the 800 kHz pressure wave from the air-coupled ultrasound transducer. (b) Temporal trace detected by an AC-coupled photodetector. The temporal response of the ring resonator (a = 90 μm) for 10.3 Pa (peak-to-peak) incident pressure wave. Inset: Spectral response of the ring resonator obtained using fast Fourier transform.
