LAUSR

In this study, we introduce a novel optical thermometer utilizing surface plasmon resonance for single‐wavelength, real‐time measurements, eliminating the need for extensive data analysis. We define operational temperature intervals and assess sensitivity to temperature variations in water within each interval, with a maximum sensitivity of approximately −1.3% per°C at an incidence angle of 66.5°. This approach offers potential integration with existing biological or chemical sensors, facilitating real‐time monitoring of both endothermic and exothermic reactions. Our results show that the thermometer is highly sensitive and accurate within a temperature range of 15°C to 45°C, with an RMSE of 0.02°C during the cooling process. Experimental data align closely with numerical calculations. Additionally, thermographic measurements provided visual and quantitative data on the temperature distribution on the sensing surface, allowing for a better understanding of the thermal behavior of the sensor. The primary advantage of this device is its ability to provide instantaneous temperature readings, making it particularly suitable for integration with existing biological and chemical sensors.