Control and stabilization of spatial mode quality in a radially polarized solid-state laser using machine learning (Conference Presentation)

2020 ◽  
Author(s):  
Thomas L. Jefferson-Brain ◽  
Matthew J. Barber ◽  
Azaria D. Coupe ◽  
William A. Clarkson ◽  
Peter C. Shardlow
Keyword(s):  
Machine Learning ◽  
Solid State ◽  
Solid State Laser ◽  
Spatial Mode ◽  
State Laser ◽  
Radially Polarized

Hydrothermal Synthesis and Solid-State Laser Refrigeration of Ytterbium-Doped Potassium Lutetium Fluoride (KLF) Microcrystals

2020 ◽  
Author(s):  
Xiaojing Xia ◽  
Anupum Pant ◽  
Xuezhe Zhou ◽  
Elena Dobretsova ◽  
Alex Bard ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Solid State ◽  
Information Science ◽  
Point Group ◽  
Solid State Laser ◽  
Lanthanide Ions ◽  
Group Symmetry ◽  
Luminescence Spectra ◽  
Crystalline Phases ◽  
State Laser

Fluoride crystals, due to their low phonon energies, are attractive hosts of trivalent lanthanide ions for applications in upconverting phosphors, quantum information science, and solid-state laser refrigeration. In this article, we report the rapid, low-cost hydrothermal synthesis of potassium lutetium fluoride (KLF) microcrystals for applications in solid-state laser refrigeration. Four crystalline phases were synthesized, namely orthorhombic K<sub>2</sub>LuF<sub>5</sub> (Pnma), trigonal KLuF<sub>4</sub> (P3<sub>1</sub>21), orthorhombic KLu<sub>2</sub>F<sub>7</sub> (Pna2<sub>1</sub>), and cubic KLu<sub>3</sub>F<sub>10</sub> (Fm3m), with each phase exhibiting unique microcrystalline morphologies. Luminescence spectra and emission lifetimes of the four crystalline phases were characterized based on the point-group symmetry of trivalent cations. Laser refrigeration was measured by observing both the optomechanical eigenfrequencies of microcrystals on cantilevers in vacuum, and also the Brownian dynamics of optically trapped microcrystals in water. Among all four crystalline phases, the most significant cooling was observed for 10%Yb:KLuF<sub>4</sub> with cooling of 8.6 $\pm$ 2.1 K below room temperature. Reduced heating was observed with 10%Yb:K<sub>2</sub>LuF<sub>5</sub>

High Power Laser Diode Arrays for Pumping Solid State Laser and Pumping Characteristics

1996 ◽  
Vol 24 (Supplement) ◽  
pp. 85-88
Author(s):  
H. Kan ◽  
T. Kanzaki ◽  
H. Miyajima ◽  
Y. Ito ◽  
K. Matsui ◽  
...  
Keyword(s):  
Solid State ◽  
Laser Diode ◽  
High Power ◽  
Solid State Laser ◽  
High Power Laser ◽  
Power Laser ◽  
State Laser ◽  
Laser Diode Arrays ◽  
High Power Laser Diode

scholarly journals Adaptive Gradient Estimation Stochastic Parallel Gradient Descent Algorithm for Laser Beam Cleanup

Photonics ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 165
Author(s):  
Shiqing Ma ◽  
Ping Yang ◽  
Boheng Lai ◽  
Chunxuan Su ◽  
Wang Zhao ◽  
...  
Keyword(s):  
Solid State ◽  
Adaptive Optics ◽  
Gradient Descent ◽  
Solid State Laser ◽  
Gradient Estimation ◽  
State Laser ◽  
Gradient Descent Algorithm ◽  
Stochastic Parallel Gradient Descent ◽  
High Output ◽  
Improved Algorithm

For a high-power slab solid-state laser, obtaining high output power and high output beam quality are the most important indicators. Adaptive optics systems can significantly improve beam qualities by compensating for the phase distortions of the laser beams. In this paper, we developed an improved algorithm called Adaptive Gradient Estimation Stochastic Parallel Gradient Descent (AGESPGD) algorithm for beam cleanup of a solid-state laser. A second-order gradient of the search point was introduced to modify the gradient estimation, and it was introduced with the adaptive gain coefficient method into the classical Stochastic Parallel Gradient Descent (SPGD) algorithm. The improved algorithm accelerates the search for convergence and prevents it from falling into a local extremum. Simulation and experimental results show that this method reduces the number of iterations by 40%, and the algorithm stability is also improved compared with the original SPGD method.

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