PHYSICS OF HIGH PERFORMANCE Yb:YAG THIN DISK LASERS

Avizonis, Petras V.; Bossert, David; Curtin, Mark S.; Killi, Alexander

doi:10.1364/cleo.2009.ctha2

Cited by 15 publications

(5 citation statements)

References 4 publications

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“…The other two are the Lambert scattering model with the diffusive reflectivity of 0.28 and 0.5, respectively. The turning points of g D th in the two models are around 0.8, which are close to g D 0.75 th ∼ observed in a disk laser [17].…”

Section: Discussionsupporting

confidence: 79%

“…As 1 B η → , the distribution of the saturated gain in the disk is equal to g th . Then the constraint on g s D transfers to the constraint on g D th , as the in experimental observations in [17]. In other words, ASE in the thin-disk lasers can be characterized by g D th approximately, which depends on the configuration of the resonator and the disk geometry, but is independent of the pumping power and the given laser dynamics.…”

Section: Discussionmentioning

confidence: 79%

“…Our basic idea in the design of experiments to verify the theoretical model is to measure the output laser power varying with the ASE intensity. In general, the ASE intensity is essentially decided by the product of g th and D [17]. Then we can modify the effects of ASE by changing the disk radius.…”

Section: Experiments Setupmentioning

confidence: 99%

See 2 more Smart Citations

A coupling model for amplified spontaneous emission in laser resonators

Wang

Shang³

et al. 2015

J. Opt.

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The competition between amplified spontaneous emission (ASE) and main laser in solid-state laser resonators is investigated both theoretically and experimentally. A coupled model using the spatial volume integral instead of the Monte Carlo type raytrace technique is proposed to depict ASE in the laser resonators. This model is able to evaluate all possible reflections at both the polishing surface and the diffusive side, to calculate ASE for an inhomogeneous gain distribution, and to include the spectral correction. An experiment is carefully designed to verify the theoretical model and to investigate the distinct physical properties caused by the coupling between ASE and the laser oscillations. The experimental data exhibit an excellent agreement with the theoretical predictions. According to that model, we confirm that ASE in thin-disk lasers can be characterized approximately by the product of the threshold gain of the resonator and the diameter of the disks, as laser modes are highly overlapped with the pumping beam. Theoretical evaluation shows that the scattering characteristic of the disk side impacts on ASE significantly. Furthermore, we point out that ASE decreases output laser power by affecting threshold pumping power, while slope efficiency is not changed by ASE. This observation provides us with a simple way to estimate the decrease of the optical efficiency by ASE.

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Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 79%

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A coupling model for amplified spontaneous emission in laser resonators

Wang

Shang³

et al. 2015

J. Opt.

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“…In 2004, Lafortune et al reported a 10 kW heat capacity solid laser, in which a traditional unstable resonator (TUR) with a uniform output-coupling fraction was adopted [3]. In 2009, Avizonis et al demonstrated a 25 kW output by combining 10 modules of Yb:YAG disk laser in an unstable resonator, using a graded reflectivity mirror (GRM) as the output coupler [4]. In 2002, Klimek and Mandl presented a thin slab laser module by employing an unstable resonator with a graded reflectivity mirror (GRM-UR) and using the scheme in which coolant liquid directly flows over the Nd: YAG thin slab [5].…”

Section: Introductionmentioning

confidence: 99%

Analysis of laser modes in high power unstable resonators with intra-cavity wavefront aberrations

Li¹,

Wang²,

Su³

et al. 2015

J. Opt.

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A semi-analytical calculation framework is proposed to calculate the eigenmodes of a general laser resonator with arbitrary intra-cavity wavefront aberrations. By solving a linear eigenvalue equation in the complex space, the mode intensity distributions of the eigenmodes in high power unstable resonators are obtained, indicating that due to the aberrations the area of fundamental mode significantly shrinks to form the localized mode with extremely high power intensity. The beam quality, mode area, threshold gain, and operation reliability are compared between the traditional unstable resonator and the one with a graded reflectivity mirror. The simulation results disclose that with a graded reflectivity mirror more high-order modes participate in mode competition and the localized mode effect of fundamental mode is weakened.

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“…M 2 ϕ 2004年德国Trumpf-Laser公司 [8] 采用多通耦合结构泵浦单个Yb:YAG薄片, 获得5.3 kW的连续激光输出, 光-光效率达到65%. 2009年美国 Boeing公司 [9]…”

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Laser-diode-array side-zigzag-pumped polygon thin-disk laser

Chen¹,

Qiu²,

Zhang³

et al. 2021

Acta Phys. Sin.

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The high-average-power diode-pumped solid-state laser is one of the main research directions in the field of international laser technology, and has major applications in the fields like space exploration, precise detection, fusion research, etc. Under high-power pumping conditions, the conventional rods or slabs are not conducive to effectively removing waste heat. And the thermal effect causes the quality of the laser beam to deteriorate, which limits the further increase of the output power. In this article, the polygonal Nd: YAG thin disk is taken as a gain medium for the laser, and experiments verify that the side pumping method can obtain a higher output power of the all-solid-state pulsed laser while ensuring high beam quality. The gain medium is a regular pentagonal Nd: YAG thin disk with a side-cut-angle of 45°, the crystal thickness is 1.5 mm, and the diameter of the inscribed circle on the front face is 16 mm. Five laser diode arrays are placed symmetrically around the disk, and the pump surfaces are parallel to the sides of the disk. The pump laser propagates along the zigzag path between the upper and lower surface of the disk, thus improving the absorptive efficiency and pump uniformity. Through the optimization study of its gain characteristics and optical characteristics, the high-efficiency high-uniform pumping is achieved. Along the pump light coupling transmission path, the fast-axis collimator is used to control the beams in the fast-axis direction to be nearly parallel, and the large-area pump light is compressed through the coupling structure of cylindrical lens and light guide to match the size of the thin disk, and the pump coupling efficiency measured experimentally is 97%. When the Nd<sup>3+</sup> doping concentration in the crystal is 0.3 at.%, the gain medium absorptive efficiency is 87%, and the root mea squared pump absorptive distribution uniformity in the gain medium is 3.21%. The fluorescence distribution of the gain medium is in good agreement with the simulated data. When the pump energy is 2.2 J, a laser output with an energy of 0.85 J is obtained, and optical-to-optical efficiency and slope efficiency are 38.8% and 40.1%, respectively. The single pulse energy stability is 2.7%(RMS) at 1 Hz frequency. In the stable cavity, the beam quality <i>β</i> - factor is measured to be about 10.

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PHYSICS OF HIGH PERFORMANCE Yb:YAG THIN DISK LASERS

Cited by 15 publications

References 4 publications

A coupling model for amplified spontaneous emission in laser resonators

A coupling model for amplified spontaneous emission in laser resonators

Analysis of laser modes in high power unstable resonators with intra-cavity wavefront aberrations

Laser-diode-array side-zigzag-pumped polygon thin-disk laser

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