Terahertz Characteristics of D2O and H2O Mixtures

D2O, which is used in nuclear power generation, is slightly different from H2O. D2O consists of deuterium (D), which is an isotope of hydrogen (H) and has one more neutron than H. D2O is heavier by about 11% than H2O, and D2O is present in water in natureat about 0.002%. Its melting point and boiling point are 3.81. and 101.42., respectively. D2O is harmful to the human body if it replaces water in the human body by more than 25% similar to 50%. We have measured the index of refractive and power absorption of 0%, 25%, 50%, 75%, and 100% of D2O in H2O using terahertz time-domain spectroscopy, and we have found that the refractive index decreases and power absorption also decreases as the concentration of D2O increases.