Dynamic range criterion of THz spectrum for amino acids measurements

Terahertz (THz) absorption spectra have been applied to measure the compositions of amino acid samples.Because the concentration information about a specific composition is involved in its spectrum, keeping the spectrum length and dynamic range as wide as possible is essential for precise measurements.It is well known that a spectrum is always contaminated by apparatus noises.In this paper, we present a criterion for noise cutting based on wavelet transform, which usually extends the range determined by traditional threshold criterion.Finally, theimprovement on measurement precision shows the validity of the new criterion.