Improvement of the spatial beam quality of laser sources with an intracavity Bragg grating

AbstractIn order to analyze the beam quality of laser sources wavefront measurements using a Shack–Hartmann sensor became an established way. With the detection of the wavefront deflection a change of the modal composition of the laser beam can be recorded directly. While this method is well known for nearly Gaussian laser beams, the wavefront analysis of broadarea semiconductor lasers is an open field of current research. Detailed analysis of the wavefront gives an additional path to get an insight into the transverse modal composition of semiconductor lasers, which have a dominant impact on the output parameters of the devices. For the presented investigations lasers emitting light in the near infrared (

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Investigation of the spatial beam quality of pulsed ns-OPOs

Applied Physics B ◽

10.1007/s00340-003-1134-6 ◽

2003 ◽

Vol 76 (5) ◽

pp. 541-545 ◽

Cited By ~ 13

Author(s):

G. Anstett ◽

A. Borsutzky ◽

R. Wallenstein

Keyword(s):

Beam Quality ◽

Spatial Beam

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Spatial Beam Self-Cleaning in Bi-Tapered Multimode Fibers

Photonics ◽

10.3390/photonics8110479 ◽

2021 ◽

Vol 8 (11) ◽

pp. 479

Author(s):

Xiao-Jun Lin ◽

Yu-Xin Gao ◽

Jin-Gan Long ◽

Jia-Wen Wu ◽

Xiang-Yue Li ◽

...

Keyword(s):

High Power ◽

Beam Quality ◽

Low Cost ◽

Nonlinear Modes ◽

Multimode Fibers ◽

Spatial Beam ◽

Self Cleaning ◽

Mode Beam ◽

Modes Coupling

We report the spatial beam self-cleaning in bi-tapered conventional multimode fibers (MMFs) with different tapered lengths. Through the introduction of the bi-tapered structure in MMFs, the input beam with poor beam quality from a high-power fiber laser can be converted to a centered, bell-shaped beam in a short length, due to the strengthened nonlinear modes coupling. It is found that the bi-tapered MMF with longer tapered length at the same waist diameter shows better beam self-cleaning effect and larger spectral broadening. The obtained results offer a new method to improve the beam quality of high-power laser at low cost. Furthermore, it may be interesting for manufacturing bi-tapered MMF-based devices to obtain the quasi-fundamental mode beam in spatiotemporal mode-locked fiber lasers.

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Improving electron beam quality of the Boeing free electron laser

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/0168-9002(91)90881-p ◽

1991 ◽

Vol 304 (1-3) ◽

pp. 336-341 ◽

Cited By ~ 3

Author(s):

D.H. Dowell ◽

M.L. Laucks ◽

A.R. Lowrey ◽

M. Bemes ◽

A. Currie ◽

...

Keyword(s):

Electron Beam ◽

Free Electron ◽

Free Electron Laser ◽

Beam Quality

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1178 J, 527 nm near diffraction limited laser based on a complete closed-loop adaptive optics controlled off-axis multi-pass amplification laser system

High Power Laser Science and Engineering ◽

10.1017/hpl.2021.3 ◽

2021 ◽

Vol 9 ◽

Author(s):

Deen Wang ◽

Xin Zhang ◽

Wanjun Dai ◽

Ying Yang ◽

Xuewei Deng ◽

...

Keyword(s):

Laser Beam ◽

Adaptive Optics ◽

Closed Loop ◽

Focal Spot ◽

Beam Quality ◽

Laser System ◽

Diffraction Limit ◽

Kdp Crystal ◽

Main Amplifier

Abstract A 1178 J near diffraction limited 527 nm laser is realized in a complete closed-loop adaptive optics (AO) controlled off-axis multi-pass amplification laser system. Generated from a fiber laser and amplified by the pre-amplifier and the main amplifier, a 1053 nm laser beam with the energy of 1900 J is obtained and converted into a 527 nm laser beam by a KDP crystal with 62% conversion efficiency, 1178 J and beam quality of 7.93 times the diffraction limit (DL). By using a complete closed-loop AO configuration, the static and dynamic wavefront distortions of the laser system are measured and compensated. After correction, the diameter of the circle enclosing 80% energy is improved remarkably from 7.93DL to 1.29DL. The focal spot is highly concentrated and the 1178 J, 527 nm near diffraction limited laser is achieved.

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