title: Vibration maps of capacitive micromachined ultrasonic transducers by laser interferometry.
abstract: In this letter, a 1.8-mm x 1.8-mm capacitive micromachined ultrasonic transducer (CMUT) element is experimentally characterized by means of optical measurements. Optical displacement measurements provide information on the resonant behavior of the single membranes and also allow us to investigate the dispersion in the frequency spectrum of adjacent membranes. In addition, higher order mode shapes are observed, showing that either symmetrical or asymmetrical modes are excited in CMUT membranes. Laser interferometry vibration maps, combined with quantitative displacement measurements, provide information about the quality and repeatability of the fabrication process, which is a basic requirement for 2-D array fabrication for ultrasound imaging.
mesh_terms: D020099:Coated Materials, Biocompatible / Q000737:chemistry; D025802:Electric Capacitance; D004867:Equipment Design / Q000379:methods; D019544:Equipment Failure Analysis / Q000295:instrumentation / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D007368:Interferometry / Q000379:methods*; D007834:Lasers; D008422:Materials Testing / Q000295:instrumentation* / Q000379:methods; D008567:Membranes, Artificial; D009038:Motion; D010087:Oxides / Q000737:chemistry; D011846:Radio Waves; D015203:Reproducibility of Results; D012117:Resins, Synthetic / Q000737:chemistry; D012680:Sensitivity and Specificity; D017655:Silicon Compounds / Q000737:chemistry; D014159:Transducers; D014465:Ultrasonics; D014732:Vibration
chemical_list: D020099:Coated Materials, Biocompatible; D008567:Membranes, Artificial; D010087:Oxides; D012117:Resins, Synthetic; D017655:Silicon Compounds; C116473:silicon monoxide; C029945:polyimide resin