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131 results on '"Kamimura, Tomosumi"'

5. Bulk laser-induced damage resistance of SrB4O7 single crystals under 266-nm DUV laser irradiation

Author

Maegaki, Yutaka, primary, Tanaka, Yasunori, additional, Marui, Haruki, additional, Koizumi, Atsushi, additional, Tanaka, Kota, additional, Kamimura, Tomosumi, additional, Murai, Ryota, additional, Takahashi, Yoshinori, additional, Empizo, Melvin John Fernandez, additional, Usami, Shigeyoshi, additional, Imanishi, Masayuki, additional, Maruyama, Mihoko, additional, MORI, Yusuke, additional, and Yoshimura, Masashi, additional

Published
2022
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10. High surface laser-induced damage threshold of SrB4O7 single crystals under 266-nm (DUV) laser irradiation

Author

Tanaka, Yasunori, primary, Murai, Ryota, additional, Takahashi, Yoshinori, additional, Sugita, Tsuyoshi, additional, Toh, Daisetsu, additional, Yamauchi, Kazuto, additional, Aikawa, Sora, additional, Marui, Haruki, additional, Umeda, Yuji, additional, Funamoto, Yusuke, additional, Kamimura, Tomosumi, additional, Empizo, Melvin John F., additional, Imanishi, Masayuki, additional, Mori, Yusuke, additional, and Yoshimura, Masashi, additional

Published
2020
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29. Exploration of Advanced Ceramic Gain Media with Broadband for the Application to High Energy Laser

Author

OSAKA INST OF TECHNOLOGY OHMIYA INFORMATION AND COMMUNICATION ENGINEERING, Kamimura, Tomosumi, Ikesue, Akio, OSAKA INST OF TECHNOLOGY OHMIYA INFORMATION AND COMMUNICATION ENGINEERING, Kamimura, Tomosumi, and Ikesue, Akio

Abstract

Practical laser generation from polycrystalline ceramic materials has become available; furthermore, it is expected that ceramic laser technology will completely surpass the conventional glass and single crystal laser technologies in the future. In this work, we fabricated advanced ceramic gain media for broadband such as CLNGG (Ca3LixNb1.5-xGa(3.5-2x)O12), CLNTGG (Ca3(LiNbTaGa)5O12)) and YSAG (Y3Sc1Al4O12), and investigated their spectroscopic properties such as emission spectrum and fluorescence lifetime. Among them, we screened the best candidate compositions for high energy laser and developed into high optical quality ceramic gain media. Nd doped Y3ScxAl5-xO12 (x = 0 to 2) ceramics was confirmed as one of the candidates for high energy laser with broadband. A composite structure with three compositions in Nd doped Y3ScxAl5-xO12 (x = 0 to 2) ceramics was successfully fabricated for the first time to obtain a broadband spectrum. The emission spectrum of multi-layered YSAG composite was more than 5 times broader compared to that of 1at% Nd:YAG. The laser oscillation test showed that multi-layered composite made of Nd:YSAG ceramics reached laser grade optical quality. Based upon the results of this work, we will apply advanced ceramic materials for high energy laser application in the future., Prepared in collaboration with World Lab. Co., Ltd., Nagoya, Japan.

Published
2013

30. High-Power Laser Oscillation Test Using Ceramic Waveguide

Author

OSAKA INST OF TECHNOLOGY (JAPAN), Kamimura, Tomosumi, OSAKA INST OF TECHNOLOGY (JAPAN), and Kamimura, Tomosumi

Abstract

Solutions to thermal problems such as temperature gradients and thermal lensing inside laser gain media are indispensable for high-power laser oscillation. This report details using ceramic bonding technology to fabricate ceramic waveguide (YAG-Nd:YAG-YAG) laser elements larger than previously described, and a preliminary investigation into their laser oscillation properties. The laser active layer (e.g., Nd:YAG, 400 um thickness) was arranged at the center, and low refractive index materials (high thermal conductive material: pure YAG with 400 um thickness) was strongly bonded at the atomic level to both faces. Sapphire was used as waveguide cladding (YAG-Nd:YAG-YAG) for higher total internal reflection. In order to investigate the optical quality of the core layer, a monolithic structure Nd:YAG slab was prepared with similar dimensions as the waveguide sample. For laser output power scaling, a newly designed sample holder was fabricated that allowed cooling ability up to around 700 W. Laser oscillation experiments will be performed once coated samples are available.

Published
2013

31. Evaluation and Understanding of the Laser Oscillation Property in Waveguides

Author

OSAKA INST OF TECHNOLOGY OHMIYA INFORMATION AND COMMUNICATION ENGINEERING, Kamimura, Tomosumi, OSAKA INST OF TECHNOLOGY OHMIYA INFORMATION AND COMMUNICATION ENGINEERING, and Kamimura, Tomosumi

Abstract

Excellent beam quality is indispensable for industrial application of high power lasers. However, high-power laser oscillation produces temperature gradients and thermal lensing inside the laser gain media resulting in laser power breakdown. This report describes fabrication of waveguide structures using Nd:YAG and YAG ceramics and investigation of their laser oscillation properties. The ceramic laser gain media evaluated was fabricated using materials controlled at macro-, micro- and nano-levels, and bonded into stacked waveguides which showed that generation of a high-power laser from a small gain medium (10mm x 32 mm) is possible. Laser output power was determined for a series of input power ranges (100-300 W, 400-600 W) and was found to increase rapidly almost linearly at 80 W or more absorbed power. Maximum output, 266 W, was momentarily achieved at approximately 680 W of absorbed power with over 46% slope efficiency without cracking the sample. Saturation of output power occurred at 260 W or greater absorbed power.

Published
2012

32. Evaluation of Laser Oscillation Property in Wave Guide Polycrystalline Ceramic

Author

OSAKA INST OF TECHNOLOGY (JAPAN), Kamimura, Tomosumi, OSAKA INST OF TECHNOLOGY (JAPAN), and Kamimura, Tomosumi

Abstract

The laser characteristics of waveguide sample manufactured by World Laboratory Co., Ltd. were evaluated. Maximum output of 120 W was obtained from approximately 264 W of absorbed power. Greater than 50% slope efficiency was achieved--the target of in this effort--without cracking the sample. However, in the region with 264 W or more absorbed power, saturation of the output power occurred. The saturation of this output is thought to be caused by a thermal cooling factor. To obtain higher output power, introducing a high-power sample cooling system is indispensable. Oscillation experiments of still-higher output are planned for a follow-on series of experiments.

Published
2011

33. Evaluation of Laser Oscillation Properties in Polycrystalline Ceramic Slabs and Waveguides

Author

OSAKA INST OF TECHNOLOGY (JAPAN), Kamimura, Tomosumi, OSAKA INST OF TECHNOLOGY (JAPAN), and Kamimura, Tomosumi

Abstract

The laser characteristics of slab/composite and waveguide ceramic sample developed and provided by Dr. Ikesue of World Laboratory Co., Ltd. were evaluated. Four kinds of three layer composite ceramic slab (Pure-0.6 or 1.0at%Nd-Pure, and Gd-0.6 or 1.0at%Nd-Gd) were prepared for this experiment. At the end-pumping laser oscillation, approximately 50% of slope efficiency was achieved in all samples.

Published
2009

39. PROGRESS IN CERAMIC LASERS

Author

Ikesue, Akio, primary, Aung, Yan Lin, additional, Taira, Takunori, additional, Kamimura, Tomosumi, additional, Yoshida, Kunio, additional, and Messing, Gary L., additional

Published
2006
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