On Quick Measurement of Airborne Ultrasound Pressure Fields

Abstract

While ultrasound has long been used in the medical field in solid and liquid mediums, it's use in air has been less thoroughly researched due to a previous lack of applications. Recently it has been used for new applications such as mid-air haptics and the levitation of small particles. These applications require accurate acoustic holograms to be generated in mid-air. In order to do so it is vital to measure accurately these pressure fields, but also quickly in order to allow for quick iteration on work, or even real-time feedback. In addition to this it is of benefit to measure the sound field without interfering with it, which microphone set ups often do due to reflections of the device used to move the microphone. This work finds these methods currently lacking, though there are techniques used in place of hydrophones in water that could be adapted to work for the in-air context such as thermography.