The space charge ellipsometric detection method provides a reliable technique for high spatial and temporal resolution measurement of insulated space charge under complex transient stress. Among them

the sensitivity of ellipsometric detection directly affects the reliability and accuracy of the measurement of weak elastic waves perturbed by charge. Therefore

this paper focuses on the sensitivity optimization of space charge ellipsometric detection. Firstly

based on elastic optical effect and Fresnel principle

the signal transmission model of the ellipsometric detection unit is established. Then

based on the pulsed electro-acoustic (PEA) measurement principle

a PEA-optical ellipsometric joint detection system is constructed and the reliability of space charge measurement of the system is evaluated. The results and experiments show that under Brewster angle incidence

the ellipsometric detection with a micron-thickness sensor has higher measurement sensitivity when the spot size of the detected light matches the area of the elastic wave signal

and the low thickness elastic optical sensor is used. The ellipsometric detection system can also measure space charge effectively and has a higher signal-to-noise ratio than the PEA space charge measurement system under the same test conditions. The work in this paper can provide important support for the development of high spatiotemporal-resolution space charge ellipsometric detection system.