Abstract-Terahertz Sensing of Chlorpyrifos-methyl using Metamaterials

Wendao Xua, Lijuan Xiea, Jianfei Zhub, Wei Wangc, Zunzhong Yea, Yungui Mab, Chao-Yin Tsaid, Su-Ming Chend, Yibin Yinga,

• ^a College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Rd., 310058 Hangzhou, PR China
• ^b State Key Laboratory for Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University, 866 Yuhangtang Rd., 310058 Hangzhou, PR China
• ^c Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
• ^d Department of Bio-Industrial Mechatronics Engineering, National Taiwan University Information, Taipei, Taiwan, R.O.C.

http://www.sciencedirect.com/science/article/pii/S0308814616314108

By squeezing electromagnetic energy into small volumes near a metal-dielectric interface, plasmonics provide many routes to enhance and manipulate light-matter interactions, which presents new strategies for signal enhancing technologies. As an extension of the ideas of plasmonics to the terahertz (THz) range, metamaterials have shown great potential in sensing applications. In this study, terahertz time-domain spectroscopy (THz-TDS) combined with metamaterials was used to detect chlorpyrifos-methyl (CM), which is one type of the broad-spectrum organophosphorus pesticides. The results demonstrate that sensitivity is greatly improved using THz metamaterials, with the limit of detection (LOD) of CM reaching 0.204 mg L^-1, which is lower than the World Health Organization’s provisional guideline limit for CM in vegetables (1 mg L^-1). The results indicated that THz spectroscopy combined with metamaterials could be a valuable method for highly sensitive THz applications, presenting a new strategy for food quality and safety control in the future.