12-14 August 2021
Lima, Perú
America/Lima timezone
Share our event through the following link: https://indico.uni.edu.pe/e/Meeting-of-Physics-2021i

Matched impedance amplifier design for Shear-Force Near-Field Acousto Microscopy

Not scheduled
Lima, Perú

Lima, Perú

Centro de Investigación de la Facultad de Ciencias Universidad Nacional de Ingeniería


Theodore Brockman (Portland State University)


Efficient detection of the acoustic signal constitutes the most critical aspect in Shear-force Acoustic Near-field Microscopy. This characterization technique utilizes the dynamic response of the fluid trapped, under shear stress, between a nanoprobe and a flat substrate. Herein we report a 10dB improvement in signal-to-noise ratio of a piezoelectric acoustic sensor using an impedance matched amplifier circuit. Data was collected utilizing the approach/retraction test method using a SiO2 flat sample and a tapered probe (a silicon pyramid or a conically shaped fiber glass). The Impedance matching capitalizes on the inherent capacitance of the acoustic sensor (a pile of piezoelectric plates) to which we add a matching inductor to optimize the signal at 32kHz (the resonance frequency of the probe) in a tank-circuit fashion. A detailed construction of the circuit amplifier, as well as detailed frequency response bandwidth and noise characterization is included herein.

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