The invention relates to a
system and a method for detecting and identifying Chinese herbal
medicine. In the invention, terahertz which is radiated from
gallium arsenide under the excitation of
femto-second
laser is used for researching Chinese herbal
medicine so as to achieve the purpose of distinguishing true and false Chinese herbal
medicine and detecting the quality of the Chinese herbal medicine. In the
system and the method, the
femto-second
laser is divided into pump light and detection light by a
beam splitter; after being modulated by a
chopper and an attenuator, the pump light is focused by a focusing lens onto the
gallium arsenide to give off the terahertz; the radiated terahertz is focused onto a tested Chinese herbal medicine sample by two parabolic mirrors; a terahertz
signal with Chinese herbal medicine information is collected and focused onto an electro-optic
crystal by another two parabolic mirrors; and detection light is also focused onto the electro-optic
crystal by a
delay device so as to detect the terahertz
signal with the Chinese herbal medicine information. The corresponding terahertz absorption spectrum is calculated after
Fourier transform, and then the Chinese herbal medicine can be quickly and effectively identified and screened by a
support vector machine method.