Terahertz Pulse Generation from Water Film Targets

Plasmas induced by the irradiation of femtosecond laser pulses are promising as future intense terahertz pulse sources. Liquid water is attractive as a target for the terahertz pulse emission from the laser-induced plasmas because of its high density and ease of continuous supply. The studies of the terahertz emission from water-based laser plasma have just started in the last few years by several groups, including the author's group. In this article, recent findings in regard with the terahertz pulse emission from water films excited by the optical pulses are reviewed, mainly based on our studies.