Signal analysis and characterization of a micro-electro-mechanical oscillator for the study of quantum fluids

Abstract

We present the full characterization of a micro-electro-mechanical system (MEMS) based probe developed for the study of quantum fluids. The device consists of a pair of parallel plates (200 × 200 μm2) with a well-defined gap (1.25 μm) in which a fluid film forms when immersed in liquid. The mobile plate is suspended above the fixed plate (substrate) by four serpentine springs. This geometry allows for the study of the properties of the surrounding liquid through the resonant behavior of the mobile plate. This device demonstrated its potential as a high precision probe suitable for the study of films of quantum fluids and also of quantum turbulence. In this work we present our detailed analysis of the device signal in our current measurement scheme. Based on our analysis, we determined the transduction factor of a device at room temperature and 4 K, which allows us to convert the measured quantities to physical quantities such as displacement, velocity, and force.