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Nishikino, Masaharu; Ishino, Masahiko; Ichimaru, Satoshi*; Hatayama, Masatoshi*; Hasegawa, Noboru; Kawachi, Tetsuya
Reza Gakkai Dai-483-Kai Kenkyukai Hokoku; Tanhacho Ryoshi Bimu Hassei To Sono Oyo, p.25 - 28, 2015/12
X-ray ablation has been recently achieved using plasma soft X-ray lasers (SXRLs), laser plasma soft X-rays, and X-ray free electron lasers. In order to study the interactions between picosecond SXRL beams and material and multi-layered structure surfaces were irradiated with SXRL pulse. Following irradiation, the substrate surface was observed using a scanning electron microscope and an atomic force microscope. The surface modifications caused by the SXRL beam were clearly seen. The multi-layered mirror is the important component for the EUV lithography. Then, we have started the damage test of multi-layered structure, and the surface modifications caused by the SXRL pulse irradiations were confirmed.
Nishikino, Masaharu; Kawachi, Tetsuya; Hasegawa, Noboru; Ishino, Masahiko; Minami, Yasuo*; Suemoto, Toru*; Onishi, Naofumi*; Ito, Atsushi*; Sato, Katsutoshi*; Faenov, A.*; et al.
X-Ray Lasers and Coherent X-Ray Sources; Development and Applications XI (Proceedings of SPIE, Vol.9589), p.958902_1 - 958902_7, 2015/09
Hasegawa, Noboru; Nishikino, Masaharu; Tomita, Takuro*; Onishi, Naofumi*; Ito, Atsushi*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Izutsu, Rui*; Minami, Yasuo*; Baba, Motoyoshi*; et al.
X-Ray Lasers and Coherent X-Ray Sources; Development and Applications XI (Proceedings of SPIE, Vol.9589), p.95890A_1 - 95890A_8, 2015/09
Times Cited Count:1 Percentile:55.52(Optics)We have improved a soft X-ray laser (SXRL) interferometer synchronized with a Ti:Sapphire laser pulse to observe the single-shot imaging of the nano-scaled structure dynamics of the laser induced materials. By the precise imaging optics and double time fiducial system having been installed, the lateral resolution on the sample surface and the precision of the temporal synchronization between the SXRL and Ti:Sapphire laser pulses were improved to be 700 nm and 2 ps, respectively. By using this system, the initial stage (before 200 ps) of the ablation process of the Pt surface pumped by 80 fs Ti:Sapphire laser pulse was observed by the comparison between the soft X-ray reflective image and interferogram. We have succeeded in the direct observation of the unique ablation process around the ablation threshold such as the rapid increase of the surface roughness and surface vibration.
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.
Hasegawa, Noboru; Tomita, Takuro*; Nishikino, Masaharu; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Minami, Yasuo*; Baba, Motoyoshi*; Onishi, Naofumi*; Ito, Atsushi*; Kawachi, Tetsuya; et al.
JAEA-Conf 2015-001, p.17 - 20, 2015/07
We have succeeded in simultaneous observation of the ablation front and the expansion front with thin filmy structure in the femto-second laser ablation process of a gold target by using the 13.9 nm soft X-ray probe (incident angle to the sample 70 deg) with soft X-ray interferometer. The dependence on the laser local fluence and materials was obtained by the comparison between gold and tungsten.
Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Onishi, Naofumi*; Ito, Atsushi*; Baba, Motoyoshi*; Minami, Yasuo*; Kawachi, Tetsuya; et al.
Reza Gakkai Dai-471-Kai Kenkyukai Hokoku; Tanhacho Ryoshi Bimu Hassei To Sono Oyo, p.9 - 12, 2014/12
no abstracts in English
Baba, Motoyoshi*; Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Minami, Yasuo*; Takei, Ryota*; Yamagiwa, Mitsuru; Kawachi, Tetsuya; Suemoto, Toru
Japanese Journal of Applied Physics, 53(8), p.080302_1 - 080302_4, 2014/08
Times Cited Count:7 Percentile:30.85(Physics, Applied)A grazing incidence reflection-type soft X-ay microscope, using a Fresnel zone plate and a soft X-ray laser with wavelength 13.9 nm and pulse width 7 ps, was developed. Submicron size groove structures made on a Pt film were clearly captured at a single shot exposure, with spatial resolution of about 360 nm. A wide field view of 100 m square was secured under the Kohler illumination. This microscope also had a large depth of focus of more than 100 m and was proven to have a sufficient performance for observing surface morphological changes.
Ochi, Yoshihiro; Hasegawa, Noboru; Suzuki, Yoji; Sukegawa, Kota*; Kawachi, Tetsuya; Kishimoto, Maki; Nagashima, Keisuke
JAERI-Tech 2004-062, 32 Pages, 2004/11
We have designed new chirp-pulse amplification (CPA) laser system for 0.1 Hz repetition rate soft X-ray laser system. We adopted the optical parametric chirped pulse amplifier (OPCPA) for a pre-amplifier because of its pulse controllability. For a main-amplifier, we decided to use a zigzag-slab amplifier because of its thermal radiation ability. In order to avoid the inhomogeneous spatial profile of the amplified laser beam, the image of the incident laser light created by a serrated aperture is transferred by use of an image relay system. In this report, we will show the preliminary test of each amplifier using a prototype system and the details of the final system design.
B.N.Chichkov*; A.Egbert*; S.Meyer*; B.Wellegehausen*; L.Aschke*; H.Kunze*; Kato, Yoshiaki
Japanese Journal of Applied Physics, Part 1, 38(4A), p.1975 - 1978, 1999/04
Times Cited Count:13 Percentile:53.04(Physics, Applied)no abstracts in English
Kawachi, Tetsuya; *; Ando, Kozo*; Hara, Tamio*; *
Inst. Phys. Conf. Ser., (159), p.211 - 214, 1999/00
no abstracts in English
Hasegawa, Noboru; Nishikino, Masaharu; Kawachi, Tetsuya; Yamagiwa, Mitsuru; Tomita, Takuro*; Suemoto, Toru; Onishi, Naofumi*; Ito, Atsushi*; Baba, Motoyoshi*; Minami, Yasuo*
no journal, ,
We have succeeded in simultaneous observation of temporal evolution of two different surfaces of the femto-second laser ablation process of metals (Au) by using the soft X-ray laser probe. The ablation front with a solid or the liquid surface and the expansion front with thin film structure were observed from the results of the soft X-ray interferogram, reflective imaging and shadowgraph. The expansion front separated from the ablation front was thin, dense and smooth so as to work as the beam splitter for the soft X-rays at the time within 1 ns after the laser irradiation. The expansion front that included almost all of the mass of the crater inside was kept at the time around 1 microsecond, and the height of that reached over 100 micron. From these results, the ablation front gradually becomes vapor while maintaining a clear and smooth expansion front.
Nishikino, Masaharu; Kawachi, Tetsuya
no journal, ,
no abstracts in English
Nishikino, Masaharu; Hasegawa, Noboru; Onishi, Naofumi*; Ito, Atsushi*; Kawachi, Tetsuya; Yamagiwa, Mitsuru; Suemoto, Toru*
no journal, ,
no abstracts in English
Nishikino, Masaharu; Hasegawa, Noboru; Kawachi, Tetsuya; Suemoto, Toru*; Onishi, Naofumi*; Ito, Atsushi*; Inogamov, N.*; Faenov, A. Y.*
no journal, ,
no abstracts in English
Kawachi, Tetsuya; Nishikino, Masaharu; Hasegawa, Noboru; Minami, Yasuo*; Baba, Motoyoshi*; Yamagiwa, Mitsuru; Kondo, Kiminori; Inogamov, N. A.*; Zakhovsky, V.*; Faenov, A. Y.*; et al.
no journal, ,
Kumada, Takayuki; Otobe, Tomohito*; Nishikino, Masaharu*; Hasegawa, Noboru*; Hayashi, Terutake*
no journal, ,
The non-thermal effect on femtosecond laser ablation has been focused on for development of high-precision micromachining technique. In this study, we newly focused on a time-resolved grazing-incidence small-angle X-ray scattering (GI-SAXS) measurement. In principle, the GI-SAXS can measure time-evolution of the morphology of the voids, which would be stretched in normal to the sample surface by the non-thermal effect. We can quantitatively evaluate the non-thermal effect from the asymmetric morphology of the voids. We succeeded in observing the scattering from a gold-deposited optical grating (1740 lines / mm), but not from a post-ablated crater on a gold plate. We have to decrease the noise level of the camera to pick up dispersed signal from disordered system such as the crater.
Kumada, Takayuki
no journal, ,
The non-thermal effect on femtosecond laser ablation has been focused on for development of high-precision micromachining technique. In this study, we newly focused on a time-resolved grazing-incidence small-angle X-ray scattering (GI-SAXS) measurement. In principle, the GI-SAXS can measure time-evolution of the morphology of the voids, which would be stretched in normal to the sample surface by the non-thermal effect. We can quantitatively evaluate the non-thermal effect from the asymmetric morphology of the voids. We succeeded in observing the scattering from a gold-deposited optical grating (1740 lines / mm), but not from a post-ablated crater on a gold plate. We have to decrease the noise level of the camera to pick up dispersed signal from disordered system such as the crater.