Thermal lensing measurement from the coefficient of defocus aberration using Shack-Hartmann wavefront sensor

Bell, Teboho; Naidoo, Darryl; Ngcobo, Sandile; Forbes, Andrew

doi:10.1117/12.2205141

Cited by 3 publications

(3 citation statements)

References 16 publications

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“…For the first approach, Shack-Hartmann Wavefront Sensors (SHWS) is most prevalent [4,7,8]. For second approach, phase-shift interferometry is more common [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Technique for thermal lens measuring using the Gerchberg-Saxton algorithm in high power laser systems

Burkov,

Tereshchenko,

Larionov

et al. 2024

J. Opt. Soc. Am. B

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In this paper, we present a first-time, to the best of our knowledge, systematic investigation into the applicability of the Gerchberg-Saxton algorithm for measuring the thermally induced phase distortion of laser beams. We propose an experimental approach based on the Gerchberg-Saxton algorithm for thermal lens measurements with optimized convergence rate and accuracy. It is shown that the method performs well in measuring optically transparent and highly scattering media, and also can provide a quantitative comparison of samples in terms of optical absorption and output beam aberrations. The dependence of the thermal lens dioptric power on the radiation power was investigated in a TGG crystal and Tb2O3 ceramic. Additionally, the possibility of estimating of the aberrations of thermal lenses was shown.

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“…For the first approach, Shack-Hartmann Wavefront Sensors (SHWS) is most prevalent [4,7,8]. For second approach, phase-shift interferometry is more common [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Technique for thermal lens measuring using the Gerchberg-Saxton algorithm in high power laser systems

Burkov,

Tereshchenko,

Larionov

et al. 2024

J. Opt. Soc. Am. B

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“…Thermal lensing is a problem that arises when lasers are used in manufacturing. 18,21 High-powered solid-state lasers can be used to manipulate the inner spatial structure of matter in a wide range of materials by repeated passes through their atomic layers. This offers great promise for applications such as rapid patterning and scanning, 22 as well as material processing, 23 and optical coherence tomography.…”

Section: Introductionmentioning

confidence: 99%

Active control of focus position of laser beams using thermally induced lensing

Bell

Mabena

Naidoo

2023

Laser Resonators, Microresonators, and Beam Control XXV

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In this paper, we present a method for active control of thermally induced lensing in high-power lasers. We used thermal lensing to study the advantages of high-power lasers. Many delivery optics are sensitive to the thermally induced lens, which can change the focus position of the transmitted beam. To compensate for this, we used thermal lensing by pumping a crystal that had no absorption or amplification at the seed beam wavelength. By controlling the strength of the heat source, we demonstrate acute control of the focus position. Our modelling work is based on the finite-volume method (FVM) to analyse thermal effects in end-pumped solid-state crystals. This work has the potential to pave the way for active control of a thermally induced lens in high-powered laser-based applications.

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“…The results of the two processes were compared. Several methods have been reported to measure the thermal focal length in the end-pumped solid-state laser [16][17][18]. The focal length of the induced thermal lens can be calculated using the ABCD matrix approach of an optical resonator [19].…”

Section: Introductionmentioning

confidence: 99%

Investigation of thermal effect on the output characteristics of end-pumped Ho:YLF laser in concave–concave and concave–convex resonators

Tooski¹,

Maleki²,

Ebadian³

et al. 2023

Laser Phys.

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The thermal effect on the output characteristics was analyzed in an end-pumped Ho:YLF laser by applying the Kirchhoff integral analytic solution and finite element analysis using LASCAD software. At a Tm:fiber laser power of 70 W, the maximum temperature of a Ho:YLF crystal with 8 mm diameter was found to be 297.6 K. The temperature distribution results of the two calculation methods were matched with an acceptable error. The calculated thermal lens focal length for the maximum power was −985 and −976 mm in the 3 and 8 mm diameter rods, respectively. The simulation results showed that for the larger diameter crystal, the thermal lens effect is less. Moreover, in this study, the calculation results were validated as experimental results. A focal length of the thermal lens of −1012.6 ± 101.26 mm at double-pass pumping was measured. The experimental study showed that laser characteristics such as the far-field divergence angle were improved in the concave–convex resonator with 0.5% Ho:YLF crystal. The experimentally measured divergence angle was 0.7 mrad, which confirms the simulation results. The output power was 13.5 W, corresponding to 19.3% optical-to-optical efficiency.

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Thermal lensing measurement from the coefficient of defocus aberration using Shack-Hartmann wavefront sensor

Cited by 3 publications

References 16 publications

Technique for thermal lens measuring using the Gerchberg-Saxton algorithm in high power laser systems

Technique for thermal lens measuring using the Gerchberg-Saxton algorithm in high power laser systems

Active control of focus position of laser beams using thermally induced lensing

Investigation of thermal effect on the output characteristics of end-pumped Ho:YLF laser in concave–concave and concave–convex resonators

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