Enhancement of Terahertz Emission from Aqueous NaCl Solutions

Exploration of terahertz sources with high electric fields and broad bandwidth is of great importance for terahertz application. In this work, the enhancement of terahertz emission from aqueous NaCl solutions induced by femtosecond laser pulses has been demonstrated by experiments. The power of the terahertz wave emission from the NaCl solution with a concentration of 30% is 1.86 times stronger than that from liquid water under equivalent excitation conditions. By means of a liquid circulation system with accurate pressure and temperature control, the influence of parameters such as solution concentration, liquid temperature, and medium size on the terahertz emission has been investigated. According to the experiment results, strong terahertz pulses are radiated from NaCl solutions with higher concentration, higher temperature, and smaller diameter. In addition, the physical mechanisms responsible for strong terahertz radiation have been analyzed by actual measurements and numerical simulations.