Index of content:
Volume 113, Issue 3, March 2003
- TRANSDUCTION 
Characterization of an optical multilayer hydrophone with constant frequency response in the range from 1 to 75 MHz113(2003); http://dx.doi.org/10.1121/1.1553457View Description Hide Description
The performance of an optical multilayerhydrophone for ultrasoundmeasurements is investigated both in theoretical terms and experimentally. The optical measurementsystem comprises a thin high-finesse dielectricinterference filter structure that is deposited onto a plane glass plate. An incident acoustic pressure wave deforms the layer system, and the induced variation of the optical reflectance is determined. Applying the concept of an optical off-axis detection scheme offers good sensitivity and a simple and low-cost setup. A primary interferometric calibration technique is applied to experimentally determine the pressure–voltage transfer function in the range from 1 to 75 MHz. Within the measurement uncertainty a constant transfer factor is obtained for the whole frequency range. Measurements of broadband ultrasound pulses are influenced neither by acoustic resonances of the very thin sensing element nor by diffraction phenomena that are known to cause waveform distortions in small probe hydrophonemeasurements. High temporal and spatial resolution is combined with high durability of the probe, which is why the optical multilayerhydrophone is well suited for use as a reference for secondary hydrophonecalibration.