SU-8 Photoresist-based Bouncing Light Sensor for Ellipsometry Detecting of the Insulation Charge

The use of ellipsometry detection in insulation charge measurement provides a viable technological approach for accurately measuring insulation charge under high frequency transient electric stress. Nevertheless, further investigation is required to thoroughly examine crucial obstacles, such as the production of terahertz excitation and the dependable detection by elasto-optical sensing. In this paper, the study on the SU-8 photoresist-based bouncing light sensor is carried out. Firstly, the hydroxyl-functionalized graphene/SU-8 photoresist composite modification method is proposed. Compared with other graphene/SU-8 photoresist composite systems, the proposed system possesses relatively higher thermal-mechanical stability. In addition, the measurement reliability of the newly created SU8 photoresist-based bouncing light sensor is assessed by comparing the results obtained from the PEA piezoelectric module with those obtained from the bouncing light sensor. This evaluation is conducted using elastic waves with a repetition frequency in the kilohertz range and a pulse width in the femtosecond range. The SU-8 photoresist-based bouncing light sensor, as compared to the piezoelectric sensor, has the capability to monitor kHz-level repeating elastic waves and femtosecond pulse-width elastic waves in real-time with reduced broadening, which could be applied to optical measurement.