Optical pressure sensor based on the combined system of a variable liquid lens and a point diffraction interferometer

Abstract

In this work we present an experimental proposal for an efficient optical pressure sensor based on a Variable Liquid Lens (VLL) and a modified Point Diffraction Interferometer (PDI). The working principle of the proposed sensor relies on the fact that a pressure variation induces a change in the lens curvature and hence in its focal length which can be tracked and measured with the interferometer. The pressure is then measured by recording and processing the interferometric images. The calibration of the sensor in this proposal demonstrated a working range of 0-26 kPa with an accuracy of less than 0.1 kPa in the whole range.