Fig 2 - uploaded by Fabrice Lefebvre
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Simulation of the reflection coefficient from longitudinal wave to shear wave for an incidence angle of 45ånd a central frequency of 1 GHz: a) Reflection coefficient with Au coating layer and b) with SiO2 deposited on mirror surfaces. Red line is the reflection coefficient from longitudinal wave to longitudinal wave, and blue line indicates longitudinal wave converted to shear wave.
Source publication
Ultra high frequency (∼1GHz) ultrasonic bulk acoustic waves (BAW) characterization has been already integrated in a lab-on–a-chip silicon platform. The acoustic wave guided in three dimensions (3D) was achieved via 45˚ mirrors in a silicon wafer and applied for the characterization of chemical solution and fluids actuation in micro-channel. The mai...
Citations
... In our case, a 1.2 lm thick gold film is matched for 500 MHz central frequency because lower frequency is better for acoustic manipulation due to lower acoustic attenuation and then most longitudinal wave energy can be kept in the wave propagation. 18,19 For acoustic actuation, a T-design is chosen to push the particles in an orthogonal direction, as shown in Fig. 1(b). A 650 MHz frequency is used considering the frequency dependent parameters, which represents the best compromise. ...
This letter presents a microfluidic device that integrates high frequency (650 MHz) bulk acoustic waves for the realization of particle handling on-chip. The core structure of the microfluidic chip is made up of a confocal lens, a vertical reflection wall, and a ZnO film transducer coupled with a silicon substrate for exciting acoustic beams. The excited acoustic waves propagate in bulk silicon and are then guided by a 45° silicon mirror into the suspensions in the microchannel; afterwards, the acoustic energy is focused on particles by the confocal lens and reflected by a reflection wall. Parts of the reflected acoustic energy backtrack into the transducer, and acoustic attenuation measurements are characterized for particle detection. Meanwhile, a strong acoustic streaming phenomenon can be seen around the reflection wall, which is used to implement particle manipulation. This platform opens a frontier for on-chip integration of high sensitivity acoustic characterization and localized acoustic manipulation in microfluidics.
