Relationship of beam quality and power for solid state laser with high average power

Qinjun, 彭钦军 Peng; Zuyan, 许祖彦 Xu

doi:10.3788/hplpb20112307.1707

Cited by 4 publications

(5 citation statements)

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“…Limited by the cooling system and the threshold of the power density, high power master oscillator and power amplifier (MOPA) laser systems selected the narrow slab as the gain medium [1][2][3][4] , this choice caused a particular phase aberration on the phase of the output laser beam due to the uniformity of the pumping and cooling, the ASE effects on the slab side, and which leaded the beam quality degrading while the laser worked at high power status [5] . The phase aberration must be corrected in time to improve the far filed focusing ability.…”

Section: System Arrangementmentioning

confidence: 99%

Beam quality active control of a slab MOPA solid state laser

Xiang

Zhang

et al. 2015

SPIE Proceedings

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The wavefront of the output high power laser beam generated by a MOPA laser system with slab gain medium was measured and analyzed by an H-S wavefront sensor, the wavefront measured consisted the static aberration of the whole optic chain and the dynamic component caused by the laser driver. Analyzing results showed that the temporal frequency of the beam aberration was mostly less than 10Hz, but the spatial distribution of the aberration was more challengeable to the phase compensation. Due to the narrow rectangle shape of the laser gain medium and the none uniformity of the pumping and cooling, it had some local big slope cross the beam section, that caused a lot of difficulties to the aberration measuring and wavefront correcting, there were many high order components in the wide direction cross the beam, but the phase aberration was more smooth in the vertical direction. A beam expander which has different ratio in the x/y directions had been used for matching the beam aperture and the valid controlling range of the deformable mirror. An adaptive optical system consisted of an H-S wavefront sensor and a deformable mirror (DM) with 67 valid actuators which arranged in two dimensions as hexagon designed to compensate the phase aberration.The driving vector of the deformable mirror was calculated from the spot array which sampled by the H-S wavefront sensor from the target beam, the surface response of all actuators were pre-calibrated and saved as a matrix. The matrix invert method was used to calculate the driving vectors in the close loop steps. The beam quality factor β was adapted to evaluate the output beam from the adaptive optical system. Simulation and experiment results of the close loop correction about the adaptive optical system showed that the aberration was compensated to a very low level and the far field beam quality of the high power laser could reach 1.67xDL. System arrangementLimited by the cooling system and the threshold of the power density, high power master oscillator and power amplifier (MOPA) laser systems selected the narrow slab as the gain medium [1][2][3][4] , this choice caused a particular phase aberration on the phase of the output laser beam due to the uniformity of the pumping and cooling, the ASE effects on the slab side, and which leaded the beam quality degrading while the laser worked at high power status [5] . The phase aberration must be corrected in time to improve the far filed focusing ability. To compensate the phase aberration

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Section: System Arrangementmentioning

confidence: 99%

Beam quality active control of a slab MOPA solid state laser

Xiang

Zhang

et al. 2015

SPIE Proceedings

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“…The implosion symmetry can be inferred from the size and shape of hotspot and cold fuel. Fusion products bring abundant information about the hotspot and fusion process [30][31][32][33][34][35][36][37][38]. X-ray and neutron imaging are used to diagnose the size and shape of the hotspot.…”

Section: Stagnation and Fusionmentioning

confidence: 99%

“…implosion experiment campaign. A-fusion-reaction-history measurement system with high temporal resolution has been used to obtain neutron emission history [36].…”

Section: Stagnation and Fusionmentioning

confidence: 99%

“…The system consists of a plastic scintillator plate, a nose cone, an optical system and a streak camera. It was first used at the SG-III prototype laser facility [36] and successfully measured the fusion reaction rate in DT implosions generating a neutron yield of about 10 10 . The results of three implosions with different CH shell thicknesses are presented in figure 15.…”

Section: Stagnation and Fusionmentioning

confidence: 99%

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Experimental progress of inertial confinement fusion based at the ShenGuang-III laser facility in China

et al. 2018

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The ShenGuang-III (SG-III) laser facility was developed by the laser fusion research center (LFRC) for inertial confinement fusion (ICF) studies in China. Over 80 diagnostics have been installed at the SG-III laser facility, including optical diagnostics, x-ray imaging diagnostics, x-ray spectrum diagnostics, fusion product diagnostics and general diagnostics assistant systems, as well as central control and data acquisition systems. Various ICF experiments have also been performed at the SG-III laser facility. The first experiment explored the laser-target coupling process, including investigations of hohlraum radiation flux and laser energy coupling efficiency. The second experiment explored ablation and implosion physics, including shell asymmetry and implosion trajectory. The third experiment explored stagnation, hotspot dynamics and the nuclear phase of the implosion.

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“…With the expansion of the application field, the demand for high power and high beam quality laser output is becoming more and more urgent. Due to factors such as thermal and nonlinear effects of the gain medium, it is difficult for the laser to guarantee both beam quality and high output power when the laser power reaches a certain level [4,8] . In order to solve this problem, beam synthesis is proposed, that is, multiple laser beams are combined by a certain method, so as to increase the laser output power.…”

Section: Introductionmentioning

confidence: 99%

Research on array laser tilt correction technology based on composite sensing

yue,

yi,

linxiong

et al. 2023

Eighteenth National Conference on Laser Technology and Optoelectronics

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In order to achieve accurate superposition of array lasers in the far field and ensure the quality of the array laser synthetic beam, it is required that the array laser sub-beams point in the same direction, i.e., there is no tilt aberration between the sub-beams. To this end, a composite sensing-based array laser tilt detection and correction method is proposed, which combines single-lens detection with microlens array detection and can achieve large dynamic range, high accuracy and high bandwidth correction to a certain extent. The basic principle of the method is: for the large dynamic range of the array laser first use microlens detection and stochastic parallel gradient descent algorithm (SPGD) for coarse correction, when the array laser sub-beam into the microlens array range, use microlens detection and PI control combined to achieve fast and high precision correction of the array laser tilt aberration. The tilt correction effect of the composite sensing-based array laser tilt correction method is compared with that of the SPGD control algorithm alone and the PI control algorithm alone, and the results show that the iteration efficiency of this method is 3.5 times higher than that of the SPGD algorithm alone for the same tilt correction results, and the synthetic beam quality is significantly improved after the tilt correction. The composite sensing-based array laser tilt aberration correction solves the contradiction between large dynamic range and high accuracy and high bandwidth to a certain extent without significantly increasing the system complexity, and effectively improves the anti-jamming ability and environmental adaptability of the array laser, which has great potential and promising application.

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Relationship of beam quality and power for solid state laser with high average power

Cited by 4 publications

References 0 publications

Beam quality active control of a slab MOPA solid state laser

Beam quality active control of a slab MOPA solid state laser

Experimental progress of inertial confinement fusion based at the ShenGuang-III laser facility in China

Research on array laser tilt correction technology based on composite sensing

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