A laser-activated MEMS transducer for efficient generation of narrowband longitudinal ultrasonic waves

Xuesheng Chen, Theodosia Stratoudaki, Steve D. Sharples, Matt Clark

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)470-476
Number of pages7
JournalIEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Volume58
Issue number2
DOIs
Publication statusPublished - 22 Feb 2011
Externally publishedYes

Keywords

  • lasers
  • optical pulses
  • optical sensors
  • optical surface waves
  • surface waves
  • transducers
  • ultrasonic imaging

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