巻号一覧
44 巻, 6 号
「ビーム結合技術を利用した高安定・高輝度レーザー」特集号
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「ビーム結合技術を利用した高安定・高輝度レーザー」特集号
特 集
レーザー解説
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椿本 孝治2016 年 44 巻 6 号 p. 356-
発行日: 2016年
公開日: 2020/12/17
ジャーナル オープンアクセスPDF形式でダウンロード (178K) -
Haik CHOSROWJAN2016 年 44 巻 6 号 p. 357-
発行日: 2016年
公開日: 2020/12/17
ジャーナル オープンアクセスLaser beam quality (BQ) and coherent beam combining (CBC) efficiency metrics are summarized and discussed. Interrelations between laser BQ, CBC efficiency metrics and phase wavefront rms deviation (or variance) are elucidated. CBC efficiency degradation sources are discussed. Examples of CBC efficiency dependence on some misalignments like optical path mismatch and phase difference, pointing instability, aberrations as well as the number of combining beams, are presented. Total efficiency of the CBC is discussed.抄録全体を表示PDF形式でダウンロード (303K) -
吉田 英次, 椿本 孝治, 藤田 尚徳, 宮永 憲明, Haik CHOSROWJAN, 北村 俊幸, 山村 健, 酒川 友 ...2016 年 44 巻 6 号 p. 363-
発行日: 2016年
公開日: 2020/12/17
ジャーナル オープンアクセスWe have developed high-peak and high-average-power polarization-maintained Yb doped PCF (Photonic Crystal Fiber) rod-fiber laser system. When the main 85 μm-PCF rod amplifier was seeded with 40 W, maximum average output power of over 210 W (pulse width: 10 ns, energy: 0.2 mJ at 1 MHz) and an excellent beam quality M2 of 1.3 was obtained. Total average power at one wavelength (four beams) was obtained to be 700~800 W. In the final fiber laser system designed for material processing applications, three units, each consisting of four coherently combined beams with over 400 W of total power, were constructed. In the final stage, output beams of those three units (1035, 1040 and 1045 nm) were combined by tiled-aperture beam combination technique, delivering more than 1.4 kW average output power at high repetition rates (75 kHz-5 MHz) with few 100 picoseconds to few10 nanoseconds pulse duration.抄録全体を表示PDF形式でダウンロード (1166K) -
原口 英介, 鈴木 二郎, 安藤 俊行2016 年 44 巻 6 号 p. 369-
発行日: 2016年
公開日: 2020/12/17
ジャーナル オープンアクセスCoherent beam combining (CBC) is the most ideal approach to obtain power and brightness scaling by maintaining the spectral and spatial properties of a single laser. CBCs are needed to maintain the optical phase differences to minimize individual lasers. In recent years, to mitigate the system complexity, CBCs have been studied with a single detector based on various phase control techniques. This paper reviews the major phase locking techniques with a single photo detector. We also present a new simultaneous detection technique for both beam pointing and optical phase using a single photo detector.抄録全体を表示PDF形式でダウンロード (639K) -
廣澤 賢一, 正田 史生, 柳澤 隆行, 神成 文彦2016 年 44 巻 6 号 p. 374-
発行日: 2016年
公開日: 2020/12/17
ジャーナル オープンアクセスThe Talbot cavity is one passive phase-locking technique for array lasers whose study is attractive due to its inherent simplicity. This paper describes the principle of the Talbot cavity and the obstacles that are impeding its commercial success. This paper also introduces our research into it using waveguide lasers. The Talbot cavity uses a compact, low-cost, high-gain waveguide laser array and successfully synchronizes the phases of the laser array while maintaining high slope efficiency. We also proposed and realized intra-Talbot-cavity frequency-doubling to convert an array of out-of-phase lasers into inphase lasers because a conventional Talbot cavity produces an out-of-phase laser array. By placing a nonlinear crystal in a Talbot cavity, the Talbot cavity generates an out-of-phased fundamental wave array, which is converted into an in-phase-locked second harmonic wave array at the nonlinear crystal.抄録全体を表示PDF形式でダウンロード (761K) -
栗田 隆史, 川嶋 利幸, 宮永 憲明2016 年 44 巻 6 号 p. 380-
発行日: 2016年
公開日: 2020/12/17
ジャーナル オープンアクセスLaser beam combining is a promising approach to increase the output power and energy of a laser system. In this article, we review several techniques of laser beam combining. Among them, we experimentally demonstrated coherent beam combining with optical parametric amplification. In a proof-of-principle experiment, the phases of two beams, which were generated from the second harmonic of a Nd: YAG laser, were precisely controlled by a motorized actuator. To demonstrate multiple-beam combining, a random phase plate was used to create random-phased beam arrays as a pump pulse. The evaluation of the far-field patterns of the pump beams, an amplified signal beam, and an idler beam demonstrated that the spatial phase uniformity of the amplified signal was maintained regardless of that of the pump beams. This feature offers a potential to produce a single beam with good beam quality from multiple beams.抄録全体を表示PDF形式でダウンロード (824K)
レーザーオリジナル
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閑林 優太, 佐々木 俊貴, 吉田 実2016 年 44 巻 6 号 p. 385-
発行日: 2016年
公開日: 2020/12/17
ジャーナル オープンアクセスCoherent-cavity combining (C3) is a power addition technique that can maintain high beam quality using coupled laser cavities. The number of laser modules that can coherently be combined in coupled cavities is limited by the mismatch of individual longitudinal modes. Our present work increases the number of coupled lasers by precise control of cavity lengths. In this paper, we report a novel C3 fiber laser with an optical-path-length control technique that uses an aluminum coated fiber (ACF) to which electric power is applied. The technique with an ACF completely consists of the longitudinal modes of two individual fiber lasers in the coupled cavity. The C3 system with ten laser modules achieved a combined efficiency of 90.2% when the technique with an ACF completely consisted of individual longitudinal modes of two out of ten laser modules.抄録全体を表示PDF形式でダウンロード (367K) -
北村 俊幸, コスロービアン ハイク , 染川 智弘, 武者 満, 井澤 靖和2016 年 44 巻 6 号 p. 390-
発行日: 2016年
公開日: 2020/12/17
ジャーナル オープンアクセスCoherent beam combining (CBC) technique using a spatial filter and stochastic parallel gradient descent (SPGD) algorithm was proposed. Estimations of CBC bandwidth for different numbers of beams and clusters, iteration steps and phase modulator bandwidths were presented. An apparatus was constructed and proof of principle experiments for 5 beams (2 clusters) in tiled aperture geometry, were performed. For phase modulator bandwidth of 1 kHz, the phase control bandwidth was theoretically estimated to be 10 Hz. The convergence time from the out-of-phase state was determined experimentally to be about 2 s.抄録全体を表示PDF形式でダウンロード (647K)
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