TY - JOUR
T1 - A laser-activated MEMS transducer for efficient generation of narrowband longitudinal ultrasonic waves
AU - Chen, Xuesheng
AU - Stratoudaki, Theodosia
AU - Sharples, Steve D.
AU - Clark, Matt
PY - 2011/2/22
Y1 - 2011/2/22
N2 - In this paper, we demonstrate an optically powered microelectromechanical system (MEMS) transducer. It was designed and fabricated using MEMS techniques, and can generate narrowband ultrasonic bulk waves from a broadband laser excitation pulse with high efficiency. The transducer is a two-mask-level MEMS device with a microdisk seated on a microstem. When a laser pulse is incident on the disk center, a resonant flapping motion of the disk is actuated because of the thermomechanical interaction between the absorbing and non-absorbing parts of the disk, coupling a narrowband longitudinal bulk wave propagating along the axis of the stem into the sample. Finite element (FE) methods were used to simulate the generated ultrasound; the results agree well with experimental measurements. Experiments with the fabricated transducers have shown that narrowband ultrasound with a high SNR/amplitude was generated successfully; compared with normal thermoelastic generation, ultrasound with at least 5 times higher amplitude can be achieved by an optimized MEMS transducer. The transducer is inexpensive, compact, and simple to use.
AB - In this paper, we demonstrate an optically powered microelectromechanical system (MEMS) transducer. It was designed and fabricated using MEMS techniques, and can generate narrowband ultrasonic bulk waves from a broadband laser excitation pulse with high efficiency. The transducer is a two-mask-level MEMS device with a microdisk seated on a microstem. When a laser pulse is incident on the disk center, a resonant flapping motion of the disk is actuated because of the thermomechanical interaction between the absorbing and non-absorbing parts of the disk, coupling a narrowband longitudinal bulk wave propagating along the axis of the stem into the sample. Finite element (FE) methods were used to simulate the generated ultrasound; the results agree well with experimental measurements. Experiments with the fabricated transducers have shown that narrowband ultrasound with a high SNR/amplitude was generated successfully; compared with normal thermoelastic generation, ultrasound with at least 5 times higher amplitude can be achieved by an optimized MEMS transducer. The transducer is inexpensive, compact, and simple to use.
KW - lasers
KW - optical pulses
KW - optical sensors
KW - optical surface waves
KW - surface waves
KW - transducers
KW - ultrasonic imaging
UR - http://www.scopus.com/inward/record.url?scp=79952035122&partnerID=8YFLogxK
U2 - 10.1109/TUFFC.2011.1824
DO - 10.1109/TUFFC.2011.1824
M3 - Article
AN - SCOPUS:79952035122
SN - 0885-3010
VL - 58
SP - 470
EP - 476
JO - IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
JF - IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
IS - 2
ER -