Insulation charge ellipsometry measurement platform and method based on photoelastic sampling principle

The invention discloses an insulation charge ellipsometry measurement platform and method based on a photoelastic sampling principle. The platform is characterized by comprising a femtosecond laser source (1), a first plane mirror (2), a second plane mirror (3), a double-electro-optical-molecule electro-optical polymer (4), a high-resistance silicon wafer (5), an off-axis parabolic mirror group (6), a high-voltage direct-current power supply (7), a photoelastic sensor (8), a helium-neon laser source (9), an optical chopper (10), a polarizer (11), a third plane mirror (12), an optical mechanical delay line (13) and a fourth plane mirror (14). The system is composed of a first plane mirror (11), a second plane mirror (12), a fifth plane mirror (15), a quarter-wave plate (16), a Wollaston prism (17), a photoelectric balance detector (18), a lock-in amplifier (19), a signal recovery correction system (20) and a delay line stepping controller (21). Terahertz pulses with picosecond pulse width are adopted at an exc