The authors would like to gratefully acknowledge research grants from National Natural Science Foundation of China (Grant No. 21706060 , 51703061 ), Natural Sciences Foundation of Hunan Province, China (Grant No. 2017JJ3103 ), the Outstanding Youth Project of Hunan Education Department (Grant No. 17B118 ) and Hunan Provincial Engineering Technology Research Center for Optical Agricultural (Grant No. 2018TP2003 ).