Efficient soft x-ray emission source at 13.5 nm by use of a femtosecond-laser-produced Li-based microplasma

• Published in: Applied physics letters Vol. 86; no. 23; pp. 231502 - 231502-3
• Main Authors: Higashiguchi, Takeshi, Rajyaguru, Chirag, Kubodera, Shoichi, Sasaki, Wataru, Yugami, Noboru, Kikuchi, Takashi, Kawata, Shigeo, Andreev, Alex
• Format: Journal Article
• Language: English
• Published: United States American Institute of Physics 06-06-2005
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABSORPTION; ELECTRON TEMPERATURE; HYDRODYNAMICS; ION TEMPERATURE; LASERS; LIGHT TRANSMISSION; LITHIUM; PHOTON EMISSION; PLASMA; PLASMA JETS; PLASMA SIMULATION; PULSES; SOFT X RADIATION; X-RAY SOURCES
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.1947890

A proof-of-principle experiment was demonstrated to optimize a Li-based microjet target coupled to dual subpicosecond laser pulses as a 13.5 nm soft x-ray emission source. An optimum pulse duration of 450 fs to achieve a maximum emission at 13.5 nm was well explained by the resonant absorption process. Utilization of dual femtosecond pulses revealed that the optimum pulse separation around 500 ps was necessary to achieve a maximum soft x-ray conversion efficiency of 0.2%, where plasma hydrodynamics could not be neglected. A one-fluid two-temperature hydrodynamic simulation reproduced this optimum pulse separation behavior.