The identification of production areas and species of Chinese curcuma is very important for quality control.In this paper,three species curcuma from two production areas are studied by terahertz time-domain spectroscopy technique and dual index sequence.The results indicated that the absorption coefficient and refractive index of the three samples were different to some extent,while they had the consistent strong absorption peaks in the range of 1.4 to 2.1 THz.The calculated results of dual indexes sequence...