Thermal behavior characterization of a kilowatt-power-level cryogenically cooled Yb:YAG active mirror laser amplifier

Chi, Han; Baumgarten, Cory; Jankowska, E.; Dehne, Kristian; Murray, Gabe; Meadows, Alexander R.; Berrill, Mark; Reagan, Brendan; Rocca, J. J.

doi:10.1364/josab.36.001084

Cited by 12 publications

(3 citation statements)

References 24 publications

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“…Cryogenic cooling has been extensively studied for scaling the power of quasi-three-level Yb 3+ -, Ho 3+ -, and Nd 3+ -doped YAG lasers [38][39][40], demonstrating prominent benefits in reducing reabsorption loss, increasing emission cross-section, and improving the thermo-optical properties of the gain media. Recent results show that monolithic Nd:YAG lasers can deliver an output power of over 30 W at 946 nm under cryogenic cooling, corresponding to a slope efficiency of up to 78% [41], which provides an efficient method for scaling the power of a 937 nm Nd:GYSGG laser.…”

Section: Nd:gysgg Laser Operating In the 09-095 μM Rangementioning

confidence: 99%

“…A successful implementation was demonstrated through a dual-band Nd:GYSGG laser at 0.94 µm and 1.06 µm [42]. As shown in Figure 8, the power ratio of the two bands could be stably and repeatably tuned at a large scale: the power proportion at 1.06 µm was tuned from 12.4 to 100% while the working temperature was increased from 2 to 20 • C under an incident pump power of 3.14 W. Cryogenic cooling has been extensively studied for scaling the power of quasi-three-level Yb 3+ -, Ho 3+ -, and Nd 3+ -doped YAG lasers [38][39][40], demonstrating prominent benefits in reducing reabsorption loss, increasing emission cross-section, and improving the thermo-optical properties of the gain media. Recent results show that monolithic Nd:YAG lasers can deliver an output power of over 30 W at 946 nm under cryogenic cooling, corresponding to a slope efficiency of up to 78% [41], which provides an efficient method for scaling the power of a 937 nm Nd:GYSGG laser.…”

Section: Nd:gysgg Laser Operating In the 09-095 μM Rangementioning

confidence: 99%

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Laser Performance of Neodymium- and Erbium-Doped GYSGG Crystals

Zhong

2019

Crystals

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Garnet crystals possess many properties that are desirable in laser host materials, e.g., they are suitable for diode laser (LD) pumping, stable, hard, optically isotropic, and have good thermal conductivity, permitting laser operation at high average power levels. Recently, a new garnet material, GYSGG, was developed by replacing some of the yttrium ions (Y3+) with gadolinium ions (Gd3+) in YSGG, demonstrating great potential as a laser host material. GYSGG crystals doped with trivalent neodymium ion (Nd3+) and erbium ions (Er3+) were successfully grown for laser generation in the near- and mid-infrared range, with some of the laser performances reaching the level of mature laser gain media. This paper gives an overview of the achievements made in Nd3+- and Er3+-doped GYSGG lasers at different wavelength ranges. Additionally, full descriptions on Q-switching, mode-locking and wavelength-selecting methods for Nd:GYSGG, and the mechanisms of power scaling by co-doping sensitizers and deactivators in Er:GYSGG, are given. It is expected that this review will help researchers from related areas to quickly gain an understanding of these laser materials and promotes their commercialization and applications.

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Section: Nd:gysgg Laser Operating In the 09-095 μM Rangementioning

confidence: 99%

Section: Nd:gysgg Laser Operating In the 09-095 μM Rangementioning

confidence: 99%

Laser Performance of Neodymium- and Erbium-Doped GYSGG Crystals

Zhong

2019

Crystals

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“…Yb-doped cryogenic solid-state lasers and amplifiers such as Yb:YAG and Yb:YLF have reached multi-100 W to kW average power levels over the last decades [1][2][3][4][5][6][7][8][9]. Further power scaling of these systems require detailed understanding of thermal effects and measurement/estimation of internal crystal temperatures during laser/amplifier operation [10][11][12][13][14]. Infrared thermal cameras that could effectively provide temperature information for room-temperature systems [15] are not effective at cryogenic temperatures.…”

Section: Introductionmentioning

confidence: 99%

Error analysis of contactless optical temperature probing methods for cryogenic Yb:YAG

et al. 2021

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In this work, we have investigated six different in situ optical contactless temperature probing methods for cryogenic Yb:YAG systems. All the methods are based on variation of fluorescence spectra with temperature, and they either look at the width of the emission line, the ratio of the emission intensity at different wavelengths and to the overall spectral change at selected wavelength intervals. We have shown that, for Yb:YAG crystal with homogeneous temperature distribution, one can perform real-time contactless optical temperature measurements with a ± 1 K accuracy in the 78–300 K range. We have further tested the methods in measuring the average temperature of Yb:YAG rods at up to 500 W absorbed pump power level. We have seen that, a real-time temperature measurement accuracy of ± 5 K is feasible in both lasing and non-lasing situations for estimating the average temperature of crystals under nonhomogeneous thermal load. The techniques are quite valuable in evaluating the bonding quality of Yb:YAG crystals in cryogenic systems. Moreover, the real-time temperature information provides feedback on parameters like cavity alignment status and extraction efficiency to the laser engineers while optimizing the system.

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Optical refrigeration of the Yb3+-doped YAG crystal close to the thermoelectric cooling limit

Zhong

Lei

Duan

et al. 2021

Applied Physics Letters

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The Yb3+:YAG crystal has been one of the most widely used active media in the solid-state lasers of high power, mainly thanks to its excellent thermal, mechanical, and optical properties. Thermal effect due to heat deposition in the active medium, however, greatly deteriorates the beam quality of the laser output and sets a limit on its maximum power available. Although the cooling proposal of anti-Stokes fluorescence can help realize the heat-free high-power lasers with good beam quality, so-called radiation-balanced lasers, there is no substantial advancement in the optical cooling of Yb3+:YAG crystals since its latest experimental report with a temperature drop of about 9 K. Here we demonstrate experimentally a remarkable temperature drop of about 80 K in a 3% Yb3+-doped YAG single crystal pumped by a fiber laser at 1030 nm. Further analysis predicts that the cooling limit of the titled crystal can reach as low as 180 K from the room temperature. Our work therefore reveals a key pathway to facilitate the optical refrigeration of the Yb3+:YAG crystal down to the thermoelectric cooling limit, thus offering a unique entry point to practical radiation-balanced lasers.

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Thermal behavior characterization of a kilowatt-power-level cryogenically cooled Yb:YAG active mirror laser amplifier

Cited by 12 publications

References 24 publications

Laser Performance of Neodymium- and Erbium-Doped GYSGG Crystals

Laser Performance of Neodymium- and Erbium-Doped GYSGG Crystals

Error analysis of contactless optical temperature probing methods for cryogenic Yb:YAG

Optical refrigeration of the Yb3+-doped YAG crystal close to the thermoelectric cooling limit

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