Electric absorption spectrum testing system and method

The invention discloses an electric absorption spectrum testing system, comprising: a light source for generating a detection light beam; the monochromator is used for splitting the detection light beam generated by the light source into monochromatic light; the adjustable diaphragm is used for changing the spot size of the monochromatic light and the luminous flux entering the sample; the sample bracket is used for fixing a sample; the light sensor is used for sensing light spots on the sample; the lens is used for collimating and focusing the detection light beam; the photoelectric detector is used for converting an optical signal reflected from the sample into an electric signal; the signal generator is used for providing a periodic modulation electric field for the sample; the oscilloscope is used for detecting a direct current part in the electric signal generated by the photoelectric detector; and the lock-in amplifier is used for detecting an alternating current part in the electric signal generated by