TY - JOUR
T1 - Soft X-ray spectral analysis of laser produced molybdenum plasmas using the fundamental and second harmonics of a Nd:YAG laser
AU - Lokasani, Ragava
AU - Kawasaki, Hiromu
AU - Shimada, Yuta
AU - Shoji, Misaki
AU - Anraku, Kyoya
AU - Ejima, Takeo
AU - Hatano, Tadashi
AU - Jiang, Weihua
AU - Namba, Shinichi
AU - Nikl, Jan
AU - Zeman, Michal
AU - O’Sullivan, Gerry
AU - Higashigu Chi, Takeshi
AU - Limpouch, Jiri
N1 - Funding Information:
Japan Society for the Promotion of Science (JP15H03570, JP16H03902, JP17K19021, JP19H04391); Ministerstvo Školství, Mládeže a Tělovýchovy (LTT17015); European Regional Development Fund (CZ.02.1.01/0.0/0.0/16_019/0000778).
Funding Information:
Japan Society for the Promotion of Science (JP15H03570, JP16H03902, JP17K19021, JP19H04391); Ministerstvo Školství, Mládeže a Tělovýchovy (LTT17015); European Regional Development Fund (CZ.02.1.01/0.0/0.0/16_019/0000778). The authors are deeply indebted to Dr. Hiroyuki Hara and Ryo Kageyama (Utsunomiya University) for useful technical support and discussion.
Publisher Copyright:
© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
PY - 2019/11/11
Y1 - 2019/11/11
N2 - Our measurement of the soft X-ray emission of Mo plasmas produced by picosecond Nd:YAG lasers emitting on the fundamental (1064 nm, 150 ps) and second (532 nm, 130 ps) harmonics is presented. The contrast in intensity between spectral peaks and the intensity outside them is lower for the second harmonic produced plasmas probably due to the presence more intense satellite emission and higher optical thickness. The measured spectra are absolutely calibrated and the observed output photon flux was (7 − 9) × 1013 photons/sr in the water-window (2.3 − 4.4 nm) spectral range for a laser energy of 160 mJ independent of laser wavelength. However, in the short wavelength range 1.5 − 2 nm, the emission using the second harmonic is strongly enhanced and is even higher than for the maximum energy of 220 mJ of the fundamental wavelength, so despite inevitable energy losses, laser wavelength conversion may lead to emission enhancement in certain spectral ranges. This enhancement is attributed to higher absorption of short wavelength laser light and higher charge state generation in denser plasmas.
AB - Our measurement of the soft X-ray emission of Mo plasmas produced by picosecond Nd:YAG lasers emitting on the fundamental (1064 nm, 150 ps) and second (532 nm, 130 ps) harmonics is presented. The contrast in intensity between spectral peaks and the intensity outside them is lower for the second harmonic produced plasmas probably due to the presence more intense satellite emission and higher optical thickness. The measured spectra are absolutely calibrated and the observed output photon flux was (7 − 9) × 1013 photons/sr in the water-window (2.3 − 4.4 nm) spectral range for a laser energy of 160 mJ independent of laser wavelength. However, in the short wavelength range 1.5 − 2 nm, the emission using the second harmonic is strongly enhanced and is even higher than for the maximum energy of 220 mJ of the fundamental wavelength, so despite inevitable energy losses, laser wavelength conversion may lead to emission enhancement in certain spectral ranges. This enhancement is attributed to higher absorption of short wavelength laser light and higher charge state generation in denser plasmas.
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U2 - 10.1364/OE.27.033351
DO - 10.1364/OE.27.033351
M3 - Article
C2 - 31878405
AN - SCOPUS:85075268631
SN - 1094-4087
VL - 27
SP - 33351
EP - 33358
JO - Optics Express
JF - Optics Express
IS - 23
ER -