Terahertz Spectroscopy of Biologically Relevant Liquids at Low Temperatures

There are a number of liquids (at room temperature), which are abundant in biological systems and are therefore of interest when studying the interaction of THz pulses with tissue. Measurements of refractive index and absorption spectra have been made on liquids in the temperature range from 90 K to 300 K and frequency range of 0.3-3.0 THz. Observations were made on the spectral changes during crystallization at the melting point and the difference between spectra at low and room temperatures were examined in an attempt to identify absorption peaks of fundamental vibrational modes.