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Kim, C. M.*; Steil, H.*; Matou
, B.*; Nishikino, Masaharu; Hasegawa, Noboru; Kawachi, Tetsuya; Tran, K. A.*; Janulewicz, K. A.*
Physical Review A, 92(4), p.043807_1 - 043807_7, 2015/10
Times Cited Count：3 Percentile：19(Optics)We present polarization measurement of a Ni-like Ag X-ray laser working in the transient collisional excitation scheme. A calibrated membrane multilayer beam splitter was used to determine the energies of two mutually perpendicular polarization components (s and p components). As a result, we observed a high degree of polarization that fluctuated from shot to shot. The dominant polarization component switched from s to p when pumping was made stronger. The measurement results are discussed from the point of view of the general polarization theory and supported by a numerical simulation based on Maxwell-Bloch equations.
Janulewicz, K. A.*; Kim, C. M.*; Steil, H.*; Kawachi, Tetsuya; Nishikino, Masaharu; Hasegawa, Noboru
X-Ray Lasers and Coherent X-Ray Sources; Development and Applications XI (Proceedings of SPIE, Vol.9589), p.95890N_1 - 95890N_7, 2015/09
Times Cited Count：0 Percentile：0(Optics)We describe measurement results on the polarization state of amplified spontaneous emission signal from a collisionally pumped Ni-like Ag soft X-ray laser with a transient inversion. The result obtained with a calibrated membrane beam splitter as a polarization state (P-state) selector shows that dominance one of the mutually perpendicular electric field components (p- or s-) in the output signal depends on the hydrodynamic state of the plasma medium. Two different hydrodynamic states were referred as a low gain and high gain regimes and the allocated P-states had dominant s- and p-component, respectively. It was also shown that due to correlations between p- and s-components in the process of coherent amplification of noise, correct description of the polarization state requires applying the generalized theory of polarization and formulated there the generalized degree of polarization.
Kawachi, Tetsuya; Sasaki, Akira; Nishikino, Masaharu; Ishino, Masahiko; Hasegawa, Noboru; Imazono, Takashi; Ochi, Yoshihiro; Tanaka, Momoko; Faenov, A. Ya.*; Pikuz, T.; et al.
no journal, ,
This paper reviews recent progress in the X-ray laser research in JAEA. In the source development, the polarization of the 13.9 nm laser has been investigated experimentally. The result indicates that the output beam is strongly polarized in the direction perpendicular to the target surface. In the alternative schemes toward the shorter wavelength region, intense higher-order harmonics with more than 300 eV has been observed from relativistic plasma generated with the laser intensity higher than 1E19 W/cm
. Furthermore, theoretical investigations of resonantly photo-pumping scheme using intense K-alpha line and generation of 
-ray flash induced by radiation damping effect are also studied. In the application study, the surface dynamics of metal plate irradiated by an optical pulse observed by X-ray laser interferometer, surface deformation induced by a single-shot XRL exposure in which nano-scale conical structures are formed, will be reported.
