High-precision temperature measurement based on weak measurement using nematic liquid crystals

Abstract

High-precision temperature measurements could guarantee temperature difference control accuracy in research and industrial production. To flexibly achieve high precision and large operating temperature range is a crucial problem for temperature measurements. Here, we demonstrate a method for a high-precision temperature measurement based on a weak measurement done using nematic liquid crystals (NLCs). By performing an analysis in the frequency domain, the temperature variation of NLCs is measured using a Sagnac interferometer with appropriate preselection and postselection. In order to obtain a large operating temperature range, there is a relatively large time delay that resulted from NLCs, and an operational principle is deduced explicitly by Jones matrices. In the proposed method, the precision of 3 × 10−6 °C could be achieved by a currently available spectrometer and the operating temperature range can be modulated by the thickness of NLCs. Moreover, the temperature sensitivity of 13.5 nm/°C could be realized for NLCs with 100 μm thickness, which exhibits at least three orders of magnitude larger than the value for other frequency domain analyses.