On Monday 20th January, Antoni Torras Rosell successfully defended his PhD project; “New measurement techniques: Optical methods for characterizing sound fields”
One of the fundamental problems in measuring the quantities that describe a sound field is the influence of the transducer on the sound field itself. Typically, this influence is assumed to be negligible when the size of the transducer is small compared with the wavelength of the sound wave or is rendered negligible by using a transducer-based correction that depends on the frequency. Either solution introduces additional uncertainties to the measurement process. The use of optical techniques may help overcome this problem because the sensing element is not a bulk transducer but a beam of light that does not influence the sound field, thus giving the actual value of the acoustic quantities.
In this project Antoni Torras Rosell investigated the acousto-optic effect for sound visualisation, acoustic holography and beamforming, and experiments confirmed the expected advantages of the optical method.
The evalutation committee was pleased with the mix of theoretical derivations, numerical modelling and carefully devised experiments in the project and was particularly impressed with Antonis breadth of knowledge.