Takamasa Suzuki

Quality measurements of KrF laser beams under high-repetition rate operation with advanced high-speed photography: preparatory experiments

Although much efforts have been made to develop higher performance excimer lasers mainly in Europe and Japan supported by the community and the government, an interdisciplinary subject in the paper title has not ever been investigated in detail. To take care of this un- attacked research region lying between various research groups, we tried to measure the beam quality of a discharge-pumped KrF laser under a rather high repetition rate operation. As we are interested in the diagnostics of various high speed phenomena, we measured the beam quality with advanced high speed photography. The spatial and temporal beam patterns were observed under various experimental conditions, and they were analyzed to start our high repetition-rate experiments. The results showed that an unstable resonator could produce high quality laser beams with the lower beam divergence angle.

Laser assisted works for pulsed ion sources: Plasma productions, diagnostics and related computations

Recent laser assisted works for pulsed ion beam drivers are described in this paper. The first one is a plasma production by a KrF laser light which may be applicable to an ion source. The second item is a transverse‐mode‐diagnostic of a discharge‐pumped laser. The third one is a one‐dimensional computation of the latter laser.

Characteristics of laser produced plasmas and lasers for pulsed ion sources

Preliminary experiments were performed to investigate the fundamental characteristics of the laser produced plasmas and the KrF lasers for the pulsed ion beam production. (1) Lithium target was irradiated by a small e‐beam pumped KrF laser and the exhausted plasmas were measured. (2) A larger KrF laser of the same kind was operated and the output characteristics were observed. (3) The mode patterns of a discharge‐pumped KrF laser was also measured most recently to prepare the future target irradiation to produce ion‐source plasmas.