Electric field vector detection method and electric field vector detection device

An electric field vector detection method for detecting an electric field vector of a terahertz wave,

• wherein ultrashort pulsed light is used as probe light and an electro-optic crystal, where a (111) surface of an optical isotropic medium is cut out, is used as a terahertz wave detection element for detecting the terahertz wave, the method comprising:
• causing polarization of the probe light to be circular polarization;
• allowing the probe light having circular polarization to enter the terahertz wave detection element and probing the terahertz wave;
• modulating the probe light, having probed the terahertz wave, by a rotating analyzer and detecting the modulated probe light by a photodetector;
• performing lock-in detection of a detection signal from the photodetector by a lock-in detector using a frequency based on a rotational frequency of the rotating analyzer as a reference signal;
• and
• detecting an electric field vector of the terahertz wave based on a detection signal from the lock-in detector.