Measurement of basis weight which is one of the most important physical indexes of paper sheet is of decisive importance in paper making process.However,this problem has not been well solved so far.Terahertz time domain spectroscopy is a newly developed spectroscopy technique based on femtosecond laser technology,and has been studied in some other research fields.The purpose of this work is to study the feasibility of applying terahertz time-domain spectroscopy technique to the measurement of paper sheet ba...