Seven-rod pumping approach for the most efficient production of TEM00-mode solar laser power by a Fresnel lens

2021 ◽  
pp. 1-28
Author(s):  
Dawei Liang ◽  
Joana Alameda ◽  
Bruno Tibúrcio ◽  
Miguel Catela ◽  
Dario Garcia ◽  
...  
Keyword(s):  
Laser Power ◽  
Fresnel Lens ◽  
Fused Silica ◽  
Laser Resonator ◽  
Radius Of Curvature ◽  
Efficient Production ◽  
Output Mirror ◽  
Tem00 Mode ◽  
Solar Pump ◽  
Pump Cavity

Abstract A seven-rod/seven-TEM00 mode beam Fresnel lens solar laser pumping approach is here proposed. The Fresnel lens with 4.0 m2 collection area was used as the primary solar concentrator to pump seven 2.5 mm diameter, 15 mm length Nd:YAG rods within a conical pump cavity through a secondary fused silica aspheric concentrator. Within the pump cavity, solar pump rays not completely absorbed by one of the seven rods were furtherly absorbed by other rods, ensuring hence a high absorption efficiency and avoiding the serious thermal lensing and thermal stress issues associated with classical large rod solar lasers. Seven individual plane-concave large-mode resonators were adopted to enable a good overlap between solar pump mode and TEM00 laser oscillating mode. By using both ZEMAX® and LASCAD® software, the maximum total TEM00 mode solar laser power of 54.65 W was numerically calculated by optimizing the radius parameter of the Fresnel lens, the diameter of the laser rod and the radius of curvature of the laser resonator output mirror. 13.66 W/m2 TEM00 mode solar laser collection efficiency and 1.44% solar power-to-TEM00 mode laser power conversion efficiency were calculated, representing substantial enhancements of 4.66 times and 4.38 times, respectively, as compared to previous experimental records of the TEM00 mode solar laser pumped through a Fresnel lens with 0.785 m2 collection area. The feasibility of TEM00 mode solar laser power delivery by hollow-core photonic crystal fibers was finally studied.

scholarly journals Zigzag Multirod Laser Beam Merging Approach for Brighter TEM00-Mode Solar Laser Emission from a Megawatt Solar Furnace

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5437
Author(s):  
Hugo Costa ◽  
Joana Almeida ◽  
Dawei Liang ◽  
Miguel Catela ◽  
Dário Garcia ◽  
...  
Keyword(s):  
Laser Beam ◽  
Laser Power ◽  
Power Level ◽  
Fused Silica ◽  
Solar Furnace ◽  
Laser Beams ◽  
Output Power Level ◽  
Mode Laser ◽  
Tem00 Mode ◽  
Pump Cavity

An alternative multirod solar laser end-side-pumping concept, based on the megawatt solar furnace in France, is proposed to significantly improve the TEM00-mode solar laser output power level and its beam brightness through a novel zigzag beam merging technique. A solar flux homogenizer was used to deliver nearly the same pump power to multiple core-doped Nd:YAG laser rods within a water-cooled pump cavity through a fused silica window. Compared to the previous multibeam solar laser station concepts for the same solar furnace, the present approach can allow the production of high-power TEM00-mode solar laser beams with high beam brightness. An average of 1.06 W TEM00-mode laser power was numerically extracted from each of 1657 rods, resulting in a total of 1.8 kW. More importantly, by mounting 399 rods at a 30° angle of inclination and employing the beam merging technique, a maximum of 5.2 kW total TEM00-mode laser power was numerically extracted from 37 laser beams, averaging 141 W from each merged beam. The highest solar laser beam brightness figure of merit achieved was 148 W, corresponding to an improvement of 23 times in relation to the previous experimental record.

scholarly journals Doughnut-Shaped and Top Hat Solar Laser Beams Numerical Analysis

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7102
Author(s):  
Miguel Catela ◽  
Dawei Liang ◽  
Cláudia R. Vistas ◽  
Dário Garcia ◽  
Bruno D. Tibúrcio ◽  
...  
Keyword(s):  
Laser Beam ◽  
Laser Power ◽  
Mechanical Performance ◽  
Power Conversion ◽  
Fused Silica ◽  
Beam Profile ◽  
Mode Laser ◽  
Laser Beam Profile ◽  
Tem00 Mode ◽  
Conversion Efficiencies

Aside from the industry-standard Gaussian intensity profile, top hat and non-conventional laser beam shapes, such as doughnut-shaped profile, are ever more required. The top hat laser beam profile is well-known for uniformly irradiating the target material, significantly reducing the heat-affected zones, typical of Gaussian laser irradiation, whereas the doughnut-shaped laser beam has attracted much interest for its use in trapping particles at the nanoscale and improving mechanical performance during laser-based 3D metal printing. Solar-pumped lasers can be a cost-effective and more sustainable alternative to accomplish these useful laser beam distributions. The sunlight was collected and concentrated by six primary Fresnel lenses, six folding mirror collectors, further compressed with six secondary fused silica concentrators, and symmetrically distributed by six twisted light guides around a 5.5 mm diameter, 35 mm length Nd:YAG rod inside a cylindrical cavity. A top hat laser beam profile (Mx2 = 1.25, My2 = 1.00) was computed through both ZEMAX® and LASCAD® analysis, with 9.4 W/m2 TEM00 mode laser power collection and 0.99% solar-to-TEM00 mode power conversion efficiencies. By using a 5.8 mm laser rod diameter, a doughnut-shaped solar laser beam profile (Mx2 = 1.90, My2 = 1.00) was observed. The 9.8 W/m2 TEM00 mode laser power collection and 1.03% solar-to-TEM00 mode power conversion efficiencies were also attained, corresponding to an increase of 2.2 and 1.9 times, respectively, compared to the state-of-the-art experimental records. As far as we know, the first numerical simulation of doughnut-shaped and top hat solar laser beam profiles is reported here, significantly contributing to the understanding of the formation of such beam profiles.

Renovating electrical power-to-TEM00 mode laser power conversion efficiency with four-lamp/four-rod pumping scheme

2021 ◽  
pp. 1-11
Author(s):  
Miguel Catela ◽  
Dawei Liang ◽  
Cláudia R. Vistas ◽  
Dário Garcia ◽  
Bruno D. Tibúrcio ◽  
...  
Keyword(s):  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Laser Power ◽  
Power Conversion ◽  
Electrical Power ◽  
Mode Laser ◽  
Tem00 Mode

Investigation of the TEM00-Mode Output Character from LD Side-Pumped Two Nd:YAG Rods in Laser Resonator

2010 ◽  
Vol 37 (10) ◽  
pp. 2467-2471
Author(s):  
董延涛 Dong Yantao ◽  
赵智刚 Zhao Zhigang ◽  
潘孙强 Pan Sunqiang ◽  
刘崇 Liu Chong ◽  
毛谦敏 Mao Qianmin ◽  
...  
Keyword(s):  
Laser Resonator ◽  
Tem00 Mode

Study on Cutting of Laser-Preheated Mullite

2011 ◽  
Vol 66-68 ◽  
pp. 2142-2147
Author(s):  
Ching Yen Ho ◽  
Mao Yu Wen ◽  
Yu Hsiang Tsai ◽  
Chung Ma
Keyword(s):  
Deformation Behavior ◽  
Laser Power ◽  
Thermal Model ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Single Point ◽  
Temperature History ◽  
Efficient Production ◽  
Cylindrical Coordinate ◽  
Cost Efficient

A thermal model for laser-assisted cutting of mullite is developed in this paper. Laser-assisted cutting has been proposed as a promising means for achieving cost-efficient production of high quality ceramic parts. At high temperatures the yield strength of ceramics can decrease below the fracture strength, changing the material deformation behavior from brittle to ductile and enabling the use of a single point cutting tool to remove material at rates approaching those of metal cutting. Assuming the system to be symmetrical and neglecting the heat loss taken away by removal material, the problem is formulated in a cylindrical coordinate system that moves with the laser beam or cutting tool. An analytical solution for this thermal model is obtained. The results calculated by this model agree with the available experimental data. The temperature history is presented during laser-assisted cutting of mullite. The effects of feed rate and laser power on temperature history are also discussed in this study.

scholarly journals Direct Laser Fabrication of Cylindrical Lenses in Wide Band Gap Materials

2019 ◽  
Vol 215 ◽  
pp. 03001
Author(s):  
Sebastian Buettner ◽  
Michael Pfeifer ◽  
Steffen Weissmantel
Keyword(s):  
Band Gap ◽  
Calcium Fluoride ◽  
Wide Band ◽  
Fused Silica ◽  
Radius Of Curvature ◽  
Projection Technique ◽  
Wide Band Gap ◽  
Laser Fabrication ◽  
Direct Laser ◽  
Direct Laser Fabrication

The Fluorine laser microstructuring technique enables the direct laser fabrication of cylindrical lenses and lens arrays thereof in wide band gap materials. For the mask projection technique, a special mask geometry was calculated, which allows the fabrication of cylindrical lenses with a nearly optimum curved surface. Based on our results of processing fused silica and borosilicate glass, we investigated the possibility to apply these microstructuring technique to wide band gap materials like calcium fluoride. The radius of curvature (ROC) can be adjusted by the process parameters laser pulse fluence and pulse-to-pulse overlap in a range of 130 to 450 µm micrometer. A minimal surface roughness of 100 nm RMS can be reached.

Assessment and Verification of a Novel Method for Near Surface Measurement of Mechanical Properties

2007 ◽  
Vol 129 (2) ◽  
pp. 314-320 ◽  
Author(s):  
S. Ozcan ◽  
K. Farhang ◽  
P. Filip
Keyword(s):  
Modulus Of Elasticity ◽  
Fused Silica ◽  
Surface Measurement ◽  
Radius Of Curvature ◽  
Near Surface ◽  
Area Function ◽  
Atomic Force ◽  
Scanning Electron Microscope Measurement ◽  
Nanoindentation Measurement ◽  
Two Parameter

A novel two-parameter area function for determination of near surface properties of Young’s modulus of elasticity and hardness has shown promise for compensating for the imperfection of the tip-end in an instrumented indentation measurement. This paper provides a comprehensive study involving a Berkovitch tip. The tip is utilized in an MTS nanoindentation measurement machine and is used to establish load indentation information for fused silica samples. The geometry of the tip is then characterized independently using a highly accurate atomic force microscope. Using the indentation data along with the two-parameter area function methodology, the tip-end radius of curvature is found to provide the most consistent value of modulus of elasticity. Independently, the data from the scanning electron microscope measurement of the same tip is used to obtain the least-squares estimation of the tip curvature. The two approaches yield favorable agreement in the estimation of tip-end radius of curvature. Therefore, the validity of the two-parameter area function method is proved. The method is shown to provide a robust, reliable, and accurate measurement of modulus of elasticity and hardness in the nanoscale proximity of a surface.

Ion Beam Figuring System for Ultra-Precise Optics

2012 ◽  
Vol 516 ◽  
pp. 19-24 ◽  
Author(s):  
Zheng Yuan ◽  
Yi Fan Dai ◽  
Xu Hui Xie ◽  
Lin Zhou
Keyword(s):  
Ion Beam ◽  
Fused Silica ◽  
Ion Source ◽  
Radius Of Curvature ◽  
Spherical Mirror ◽  
Gaussian Shape ◽  
Vacuum Chambers ◽  
Effective Aperture ◽  
Flat Mirror ◽  
Ion Beam Figuring

Ion beam figuring (IBF) is a novel technology for Ultra-precise optics. Material is removed from optic surface in atomic or molecular form by physical sputtering. Due to non-contact between the tool and the work piece, the problems involved in the conventional process are avoided, such as edge-effect and tool-wear. The ion beam figuring process is of high determinacy and high efficiency. All these properties make ion beam figuring one of the promising methods for producing mirrors of high precision with nm-rms accuracy. In this article, a new ion beam figuring system which contains doubled vacuum chambers is set up. Optics can be exchanged by a transport vehicle shuttling between the two vacuum chambers without opening the primary vacuum chamber and waiting for the ion source to cool completely, which means the efficiency can be increased greatly. A high performance processing robot contains three linear axes and two angular axes of motion, providing 5-axis ion source positioning capability with high accuracy. The angle can be up to 50° to figure very steep spherical and aspherical surfaces. Then, the beam removal function of Gaussian shape is obtained by an experimental method and it is extremely stable for a long time. Finally, two sample mirrors are figured by the ion beam figuring system: one is a fused silica flat mirror with a 100 mm diameter (90% effective aperture) and an ultra-precise flat mirror with a surface error of 0.89 nm rms, 14.7 nm PV is obtained; the other fused silica concave spherical mirror with a 100 mm aperture (90% effective aperture) and 420 mm radius of curvature is figured and a concave spherical mirror with 1 nm rms, 16.9 nm PV is obtained, which prove that the ion beam figuring system is favourable for the figuring process.

Mirror with a variable amplitude – phase reflectance. 2. Modelling of a laser resonator with an active output mirror

2011 ◽  
Vol 41 (3) ◽  
pp. 239-242 ◽  
Author(s):  
V V Kiiko ◽  
V I Kislov ◽  
Evgenii N Ofitserov
Keyword(s):  
Laser Resonator ◽  
Output Mirror ◽  
Variable Amplitude

Analysis of a Cylindrical Laser Resonator Having a Zoned Output Mirror

1970 ◽  
Author(s):  
George A. Emmons
Keyword(s):  
Laser Resonator ◽  
Output Mirror
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