The film thickness detection with temperature self-compensating based on integrated resonance and interfer-ence effects
To address the issue of plastic film thickness measurement being significantly affected by am-bient temperature,we proposed a self-compensation method that involved measuring the temperature of the film.This method combines a microfiber loop resonator(MLR)and a Fabry-Perot(F-P)interferom-eter.The MLR,coated with polydimethylsiloxane(PDMS),is used to monitor temperature changes,while the F-P cavity formed on the front and back surfaces of the film is used to measure the thickness.By considering the combined effect of MLR and F-P interference in the reflection spectrum,we can sim-ultaneously demodulate the temperature and film thickness using a single light source and demodulation device.This achieves temperature self-compensation for film thickness measurement.The experimental results demonstrate that our sensor method can accurately detect changes in film thickness caused by temperature fluctuations.The temperature sensitivity is 166 pm/℃,and successful temperature self-compensation is achieved within the temperature range of 25-55 ℃.After temperature compensation,the maximum relative error is reduced from 0.51%to 0.11%.In comparison with other thickness measurement methods,our technology offers a solution that integrates temperature compensation into the thickness measurement sensor.It provides numerous advantages,including high sensitivity,non-de-structive testing,rapid detection,and measurement unaffected by temperature.Therefore,it has great potential for applications in the petrochemical and biological detection fields,as it can enhance the effi-ciency and accuracy of thickness measurement for thin films.