Influence of thermal reduced depolarization on a repetition-frequency laser amplifier and compensation

Jiang, Xiaotong; Xia, Yan; Wang, Zhenguo; Zheng, Jiangang; Li, Mingzhong; Su, Jingqin

doi:10.1017/hpl.2015.4

Cited by 6 publications

(3 citation statements)

References 3 publications

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“…In this work, benefiting from the thermal management of the microchannel heat sink, the beam quality degradation was not severe when the pump power exceeded 300 W. By using a seed laser with good beam quality, the beam quality of the Yb:YAG main amplifier can be improved, as shown in our previous work [30]. We believe that the increase in thermal depolarization power indicates that the temperature distribution of the thin rod changes with high pump power, because thermal depolarization is positively correlated with thermal loading [31], [32]. As shown in the inset of Figure 5, the amplified beam profile was elliptical, because the thermal conductivity of thermal grease (6 Wm -1 K -1 ) at the heat sink junction was lower than that of copper (400 Wm -1 K -1 ), resulting in uneven heat dissipation in the horizontal and vertical directions.…”

Section: Resultsmentioning

confidence: 80%

Compact 80 W, 1 MHz Femtosecond Chirped Pulse Amplification Laser System Based on a Yb-Doped Fiber and a Yb:YAG Thin Rod

Peng

Shi

et al. 2022

IEEE Photonics J.

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We present a hybrid chirped pulse amplification (CPA) laser system based on Yb-doped fiber and Yb:YAG thin rod. The laser system demonstrates a novel approach to generate high average power up to the 100-W level by using a Yb:YAG thin rod without pump guiding at room temperature. A Yb-doped allfiber laser with an output power of 7 W and a repetition rate of 1 MHz is amplified to an output power of 126.2 W in simple and compact two-stage amplifiers consisting of a single fiber crystal (SCF) and a Yb:YAG thin rod. To the best of our knowledge, this is the highest output power of Yb:YAG thin-rod amplifier with good beam quality obtained without pump guiding at room temperature. After using a thin-film polarizer (TFP) to remove the thermal depolarization, a linearly polarized ultrashort pulse laser with an average power of 115.2 W is obtained. An output power of 80.6 W with a pulse width of 580 fs is achieved after pulse compression. The central pulse contains 84.1% of the total pulse energy, corresponding to a pulse peak power of 116.9 MW.

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Section: Resultsmentioning

confidence: 80%

Compact 80 W, 1 MHz Femtosecond Chirped Pulse Amplification Laser System Based on a Yb-Doped Fiber and a Yb:YAG Thin Rod

Peng

Shi

et al. 2022

IEEE Photonics J.

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“…The SMS design was used in Refs. [19][20][21][22] before which suppressed Raman emission and reduced SPMinduced linewidth broadening. However, in this design we attempted to use polarization-maintaining (PM) fibers to kW-level, narrow-linewidth linearly polarized fiber laser with excellent beam quality through compact one-stage amplification scheme 3 construct an SMS cavity.…”

Section: Methodsmentioning

confidence: 99%

kW-level, narrow-linewidth linearly polarized fiber laser with excellent beam quality through compact one-stage amplification scheme

Jiang

Huang

et al. 2017

High Pow Laser Sci Eng

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In this manuscript, we demonstrate high-power, narrow-linewidth linearly polarized fiber laser with excellent beam quality through compact one-stage amplification scheme. By employing a single-mode-multimode-single-mode structure seed laser, a linearly polarized Yb-doped fiber laser with narrow linewidth and high output power is achieved. This laser, when used as a master oscillator, can be capable of suppressing the ASE in the process of power amplification. Thus, only one-stage amplification structure is used to scale up the laser power, and linearly polarized output with a polarization extinction ration of 14 dB, a narrow linewidth of 0.3 nm and an output power of 1018 W are achieved. Moreover, due to the good beam quality of seed laser and the well-designed amplifier stage, the beam quality of the output laser is near-diffraction-limited with M 2x ∼ 1.18 and M 2 y ∼ 1.24 at the maximum power, and without mode instability occurring.

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“…High-repetition-rate lasers with high pulse energy and exceptional beam quality find broad applications in space debris detection, lidar ranging and laser nonlinear effects [1][2][3][4] . Nevertheless, the high-power pumping in conventional master oscillator power amplifier (MOPA) systems induces thermal depolarization and thermal focusing effects, which in turn cause an increase in the beam divergence angle and a decrease in spatial distribution [5][6][7] . Stimulated Brillouin scattering (SBS) is an effective method to achieve temporal, frequency and spatial modulation of laser beams [8][9][10][11][12] .…”

Section: Introductionmentioning

confidence: 99%

Characteristics and suppression of beam distortion in a high repetition rate nanosecond stimulated Brillouin scattering phase conjugation mirror

Chen,

Tan,

Jin

et al. 2024

High Pow Laser Sci Eng

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The stimulated Brillouin scattering phase conjugation mirror (SBS-PCM) based on liquid media is widely used in highpower laser systems due to its robust thermal load capacity, high energy conversion efficiency and improved beam quality. Nevertheless, with an increase in the pump repetition rate, thermally-induced blooming and optical breakdown can emerge, leading to distortions in the Stokes beam. In this study, we delved into the thermal effects in liquid SBS-PCMs employing hydrodynamic analysis, establishing a relationship between beam profile distortion and the thermal convection field. We calculated the temperature and convection velocity distribution based on the pump light parameters and recorded the corresponding beam profiles. The intensities of the beam profiles were modulated in alignment with the convection directions, reaching a velocity peak of 2.85 mm/s at a pump pulse repetition rate of 250 Hz. The residual sum of squares (RSS) was employed to quantify the extent of beam profile distortion relative to a Gaussian distribution. The RSS escalated to 7.8, in contrast to 0.7 of the pump light at a pump pulse repetition rate of 500 Hz. By suppressing thermal convection using a high-viscosity medium, we effectively mitigated beam distortion. The RSS was reduced to 0.7 at a pump pulse repetition rate of 500 Hz, coinciding with a twentyfold increase in viscosity, thereby enhancing the beam quality. By integrating hydrodynamic analysis, we elucidated and mitigated distortion with targeted solutions. Our research offers an interdisciplinary perspective on studying thermal effects and contributes to the application of SBS-PCMs in high-repetition-rate laser systems by unveiling the mechanism of photothermal effects.

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Influence of thermal reduced depolarization on a repetition-frequency laser amplifier and compensation

Cited by 6 publications

References 3 publications

Compact 80 W, 1 MHz Femtosecond Chirped Pulse Amplification Laser System Based on a Yb-Doped Fiber and a Yb:YAG Thin Rod

Compact 80 W, 1 MHz Femtosecond Chirped Pulse Amplification Laser System Based on a Yb-Doped Fiber and a Yb:YAG Thin Rod

kW-level, narrow-linewidth linearly polarized fiber laser with excellent beam quality through compact one-stage amplification scheme

Characteristics and suppression of beam distortion in a high repetition rate nanosecond stimulated Brillouin scattering phase conjugation mirror

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