Sensitivity improvement in electro-optic imaging based on polarization CMOS image sensor

In this study, we discuss the maximum signal-to-noise ratio (SNR) at 1 GHz in the electric field imaging system that we have developed using the electro-optic (EO) effect. To increase the detection sensitivity of electric field imaging, weak polarization changes must be detected. To increase the detection sensitivity while avoiding pixel saturation of the image sensor, we propose a structure in which a uniform polarizer is directly above the polarization image sensor. This increases the polarization modulation and reduces the incident light intensity, enabling a large amount of light to be incident on the EO crystal. The results of SNR measurements by varying the incident light intensity, we consider that an SNR of 57 dB or higher can be expected at an incident light level of 24 dBm or higher.