title: Characterization of micromachined ultrasonic transducers using light diffraction tomography.
abstract: This paper demonstrates that light diffraction tomography can be used to measure the acoustic field of micromachined ultrasonic transducers (MUT) in cases in which standard methods like hydrophone and microphone measurements fail. Two types of MUTs have been characterized with the method, one air-coupled capacitive MUT (cMUT) and one waterloaded continuous wave (CW) miniature multilayer lead zirconate titanate (PZT) transducer. Light diffraction tomography is an ultrasound measurement method with some special characteristics. Based on the interaction of light and ultrasound, it combines light intensity measurements with tomography algorithms to produce a measurement system. The method offers nonperturbing pressure measurements with high spatial resolution. It has been shown that, under certain circumstances, light diffraction tomography can be used as an absolute pressure measurement method with accuracy in the order of 10% in water and 13% in air. The results show that air-coupled cMUTs in the frequency range of about 1 MHz as well as the extreme near field of a miniaturized CW 10 MHz water-loaded transducer were successfully characterized with light diffraction tomography.
authors.affiliation: Department of Electrical Measurements, Lund Institute of Technology, Lund, Sweden.
authors.forename: Monica
authors.initials: M
authors.lastname: Almqvist
authors.forename: Marcus
authors.initials: M
authors.lastname: Törndahl
authors.forename: Mikael
authors.initials: M
authors.lastname: Nilsson
authors.forename: Tobias
authors.initials: T
authors.lastname: Lilliehorn
mesh_terms: D003198:Computer Simulation; D025802:Electric Capacitance; D004582:Electronics, Medical; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods*; D008027:Light; D008567:Membranes, Artificial; D008839:Microelectrodes; D008904:Miniaturization; D012031:Refractometry / Q000379:methods*; D041622:Tomography, Optical / Q000379:methods*; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods*
chemical_list: D008567:Membranes, Artificial