A note on the use of novel thermoacoustic radiators for ultrasonic experiments: the importance of phase in a focused field

The use of a novel thermoacoustic transducer facilitates the study of ultrasonic fields; with this aim, a description of its simple construction is given. In particular, an experiment with a spherically curved source is presented, where the theoretical acoustic pressure obtained by a numerical approximation shows, by comparing with the experimental results, the importance of taking into consideration the phase of the radiated sound on the field produced by focusing sources. The type of thermoacoustic transducer presented in this paper radiates sound in the audible and ultrasonic regions, without resonances, up to at least 100 kHz. These features, along with their ease of construction, allow the use of large, planar or curved, acoustic radiators in laboratory experiments.