Single-element real-time interferometric system for measuring dynamic temperature field of liquid medium

Abstract

Temperature plays an important role in biomedicine and industrial production. In this study, we demonstrate a simple and reliable real-time interferometric system based on a single-element for measuring the dynamic temperature field of liquid media. In the proposed system, the reference beam and the object beam enter the beam splitter cube with a splitting ratio of 50:50 to produce interference fringes. The interference light arrives at the observation plane of a CMOS camera after being attenuated, which is capable of monitoring the change process of space carrier phase shift distribution in real time. The common optical path design eliminates the environmental disturbance. The phase shift of the interferograms as the optical path difference between the reference beam passing through liquid and the object beam passing through air is calculated by fast Fourier transform. The temperature changes of 50% polyacrylamide hydrogel (25–65 °C), 4% NaCl (25–65 °C), and ethanol (20–60 °C) were measured by our proposed system. During the experiment, we successfully measured the dynamically changing temperature field of deionized water subjected to a heating and cooling process (25–40 °C). The proposed system offers the advantages of compact structure, high efficiency, long-term stability, and low cost, and it is expected to assist non-contact measurements and biomedical research, making it a viable reference candidate for the field of environmental ecology and medicine.