Paths to the Production of Water Window X Ray with Laser Plasmas
Wang Xiaofang Zhang Zhengquan Fan Pinzhong Xu Zhizhan (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800)
Various approaches to the production of soft x ray in the water window (2.3-4.4 nm) and the nearby wavelength range are discussed. Atomic number of the material used as target is the most fundmental factor which affects x ray production and conversion efficiency. High intense x rays can be realized with laser plasmas in nonequilibrium or in equilibrium state, and that x rays from black body sources produced by laser plasmas in equilibrium state be used for x ray microscopy of living samples is proposed. With the present lasers, x ray microscopy can be made using narrow band emission or black body radiation from laser plasmas. The black body x ray source produced by high intense femtosecond laser interaction with solids of high atomic number is useful in time resolved spectroscopy as well as in x ray microscopy.