Microscale diffusers for absorption of ultrasound.

Although diffusers are used primarily for enhanced scattering, they can be designed to absorb sound as part of an anechoic surface. In this study, microscale diffusers are investigated for their antireflection properties in the ultrasonic frequency regime (above 1 MHz). Computations indicate that periodic surface structures on the order of a few to a dozen micrometers can lead to a dramatic reduction in pressure reflection coefficient at frequencies commonly encountered in medical ultrasonics. Possible applications include the design of a thermally resistant absorbing target for a radiation force balance in high‐intensity focused ultrasound power measurement.