A New Optical Voltage Sensor Based on Radial Polarization Detection

A new optical voltage sensor based on radial polarization detection is proposed in this paper, and then the linear and direct measurement of an electro-optic (EO) phase delay can be realized. The sensor mainly consists of an EO crystal, a quarter-wave plate, a newly designed radially polarized grating, and an image collecting system. The quarter-wave plate is employed to convert the EO phase delay to a rotation of the polarization plane of a linearly polarized light, and then the grating is to convert it into the rotation of a ring facular, so the EO phase delay can be measured directly by positioning the dark stripe center in the facular. The principle of the sensor is analyzed by Jones matrix. The experimental results show that this new sensor can achieve a good linear measurement of the EO phase delay in the range of 360° with the measurement error less than 0.5%, and has no limits of the half-wave voltage of crystal.