Method and device for determining incident angle of terahertz wave reflection measurement system

The invention relates to a method for determining an incident angle of a terahertz wave reflection measurement system. The method comprises the following steps of: obtaining a first calibration plateand a second calibration plate by a terahertz wave transmission measurement, wherein the first calibration plate is taken as the electric field intensity of the terahertz wave transmission of a sampleto be measured, and the second calibration plate is taken as the electric field intensity of the terahertz wave transmission when no sample is measured, so as to obtain complex refractive indexes ofthe first calibration plate and the second calibration plate; at a certain incident angle, obtaining the electric field intensities of the terahertz wave reflection separately reflected by the first calibration plate and the second calibration plate by a terahertz wave reflection measurement; separately solving reflection coefficient expressions of the two according to the complex refractive indexes of the first calibration