Interferometric phase shift compensation technique for high-power, tiled-aperture coherent beam combination

Chosrowjan, Haik; Furuse, Hiroaki; Fujita, Masayuki; Izawa, Yasukazu; Kawanaka, Junji; Miyanaga, Noriaki; Hamamoto, Koichi; Yamada, Takahiro

doi:10.1364/ol.38.001277

Cited by 29 publications

(9 citation statements)

References 13 publications

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“…In a tiled-aperture CBC, several sub-beams propagate through their respective amplifiers and compressors, parallel to the same focusing element. The peak intensity of the CBC focal spots is N 2 of a single sub-beam [17]. Therefore, the final output of the laser is no longer limited by the full size of the crystals and gratings.…”

Section: Introductionmentioning

confidence: 99%

“…To improve the feasibility of this technique for ultra-intense ultra-short laser devices, both theoretical and experimental studies have been carried out in high-power laser fields [17][18][19][20][21][22]. However, these studies were mostly based on two sub-beams, with only one article reporting a phasing method of tiledaperture CBC based on three sub-beams.…”

Section: Introductionmentioning

confidence: 99%

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Four-Beam Tiled-Aperture Coherent Beam Combining of High-Power Femtosecond Laser With Two Compressors

Peng¹,

Li²,

Liang³

et al. 2022

IEEE Photonics J.

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The former reports of coherent beam combining (CBC) in the ultra-intense ultra-short laser field focus on the phase control technology and two-beam CBC. To study the four-beam tiled-aperture CBC in the ultra-intense and ultra-short laser field, we demonstrate four-beam CBC of femtosecond laser pulses based on chirped pulse amplification (CPA) scheme. In this experiment, the four beams were compressed using two grating compressors to simulate the situation in ultra-intense and ultra-short laser CBC systems. To achieve real-time measurement of the phase error between the four beams, we introduced a continuous reference laser and the phases of beams 2, 3, and 4 were locked to beam 1.A combined efficiency of 57% was achieved. Although the coherent combining efficiency is not very high, the possibility of a fourbeam CBC based on the CPA scheme was confirmed, especially with different grating compressors which can reduce the limitation of gratings in single beam petawatt lasers. Finally, the remaining difficulties in the implementation of CBC of four beams and the methods to improve its efficiency were analyzed. The use of CBC in ultra-intense and ultrashort laser systems is of considerable significance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Four-Beam Tiled-Aperture Coherent Beam Combining of High-Power Femtosecond Laser With Two Compressors

Peng¹,

Li²,

Liang³

et al. 2022

IEEE Photonics J.

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“…The core challenge of achieving a co-phase output is to correct and lock the piston phase quickly between each sub-beam [13][14][15][16][17][18][19]. In the past, a series of phase-locking methods have been proposed, including the dithering technique [20][21][22], interference measurement [23,24], and stochastic parallel gradient descent (SPGD) [25,26]. The dithering technique and the interference measurement method need to add new devices to the CBC system.…”

Section: Introductionmentioning

confidence: 99%

Discussion on Piston-Type Phase Ambiguity in a Coherent Beam Combining System

et al. 2022

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Coherent beam combining (CBC) with closely arranged centrosymmetric arrays is a promising way to obtain a high-brightness laser. An essential task in CBC is to actively control the piston phases of the input beams, maintaining the correct phasing to maximize the combination efficiency. By applying the neural network, the nonlinear mapping relationship between the far-field image and the piston phase could be established, so that the piston phase can be corrected quickly with one step, which caused widespread concern. However, there exists a piston-type phase ambiguity problem in the CBC system with centrosymmetric arrays, which means that multiple different piston phases may generate the same far-field image. This will prevent the far-field image from correctly reflecting the phase information, which will result in a performance degradation of the image-based intelligent algorithms. In this paper, we make a theoretical analysis of phase ambiguity. A method to solve phase ambiguity is proposed, which requires no additional optical devices. We designed simulations to verify our conclusions and methods. We believe that our work solves the phase ambiguity problem in theory and is conducive to improving the performance of image-based algorithms.

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“…Most of times, in this context, the wavefront to control takes the form of a discrete distribution of phase steps (piston-phase). Some phase-locking techniques have the capability to shape any desired discrete wavefront but they require a fast measurement of the instantaneous individual phase of the whole beams of the emitter array either with help of a reference plane wave [9] or with shearing interferometry method [10]. Beam pointing on a distant target through turbulent atmosphere requires also the proper adjustment of the phase pattern in the beam array launched toward the target.…”

Section: Introductionmentioning

confidence: 99%

Random Scattering and Alternating Projection Optimization for Active Phase Control of a Laser Beam Array

et al. 2019

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A fraction of a laser beam array, whose unknown piston phase relationships must be set to prescribed values, is launched into a scattering media with random transmission. The resulting output speckle pattern is sampled by an array of photodiodes measuring the local light intensity. The data feed an innovative optimization process which controls a phase modulator array. Few iterations of the opto-numeric loop lead to efficient and fast phase locking on any desired piston phase distribution.

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Interferometric phase shift compensation technique for high-power, tiled-aperture coherent beam combination

Cited by 29 publications

References 13 publications

Four-Beam Tiled-Aperture Coherent Beam Combining of High-Power Femtosecond Laser With Two Compressors

Four-Beam Tiled-Aperture Coherent Beam Combining of High-Power Femtosecond Laser With Two Compressors

Discussion on Piston-Type Phase Ambiguity in a Coherent Beam Combining System

Random Scattering and Alternating Projection Optimization for Active Phase Control of a Laser Beam Array

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