Acoustic hologram (IMAGE) Virginia Tech Caption Acoustic hologram assembly. It includes an oscillating disk to generate a sound field under water, a 3D-printed metallic mirror, and a hydrophone for measuring the acoustic pressure pattern formed with sound waves that are reflected from the mirror plate Credit Ahmed Sallam for Virginia Tech Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.