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Title: Lamb Wave Focusing Transducer for Efficient Coupling to Wavelength-Scale Structures in Thin Piezoelectric Films

Journal Article · · Journal of Microelectromechanical Systems
ORCiD logo [1];  [2];  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Defense Advanced Research Project Agency, Arlington, VA (United States)

This study describes the theoretical and experimental investigation of interdigitated transducers (IDTs) capable of producing focused acoustical beams in thin film piezo-electric materials. A mathematical formalism describing focused acoustical beams, Lamb beams, is presented and related to their optical counterparts in two- and three-dimensions. A novel Fourier domain transducer design methodology was developed and utilized to produce near diffraction limited focused beams with in a thin film AlN membrane. The properties of the acoustic beam formed by the transducer were studied by means of Doppler vibrometry implemented with a scanning confocal balanced homodyne interferometer. Fourier domain modal analysis confirmed that 85% of the acoustical power was delivered to the targeted focused beam which was constituted from the lowest order symmetric mode, while 2% was delivered unintentionally to the beam formed from the anti-symmetric mode, and the remaining power was isotropically scattered. The transmission properties of the acoustic beams as they interact with devices with wavelength scale features were also studied, demonstrating minimal insertion loss for devices in which a subwavelength, pinhole apertures was included.

Research Organization:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
AC04-94AL85000
OSTI ID:
1452667
Report Number(s):
SAND-2018-2363J; 661166
Journal Information:
Journal of Microelectromechanical Systems, Journal Name: Journal of Microelectromechanical Systems; ISSN 1057-7157
Publisher:
IEEECopyright Statement
Country of Publication:
United States
Language:
English

Cited By (2)

Piezoelectric Transduction of a Wavelength-Scale Mechanical Waveguide journal February 2020
Piezoelectric transduction of a wavelength-scale mechanical waveguide text January 2019

Figures / Tables (28)