Temperature Measurements in Glass Sheets Using Phase-Sensitive Optical Coherence Tomography.

Abstract

In this work, we propose the indirect measurement of temperature in a glass sheet by measuring the optical path difference (OPD) between the two surfaces of the sheets. The OPD values are obtained using phase-sensitive optical coherence tomography (PhS-OCT). The experimental setup is presented, featuring a broad spectral width light source of 180 nm, along with the system for detecting and processing the interference signal generated between the reflections from both surfaces of the sheet. The phase of the Fourier transform of the obtained interference signal is used to determine the OPD. We present OPD results obtained from scans across a glass sheet at room temperature, aiming to analyze the repeatability of the measurements and assess the feasibility of establishing a temperature reference line for measurements at different points on the sheet. Initial results in the calibration of temperature as a function of OPD are also shown, indicating an OPD variation between 16 and 17 nm per degree Celsius. The experimental results are compared with those obtained from computational simulations conducted using the Finite Volume Method.