Developing a power laser with averaging power from several 100 W to several kW opened the inspecting infrastructure and new industry. In topical issues, the authors have introduced the advanced power lasers state of arts and its industrial application all over the world.

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In the last decades, ultrafast thin-disk lasers have significantly matured into robust industrial products, capable of providing nearly millijoule pulses, kilohertz repetition rates and picosecond pulse durations for 24/7 (24 hours a day/7 days a week) manufacturing operations. In scientific research, the need to extend the power and energy level has further driven the development of advanced thin-disk solutions enabling experimental breakthroughs and uncovering exciting new applications. In particular, large-scale laser facilities have given incentive to build robust kW-class ultrafast lasers with hundreds of millijoules. In this contribution, we present our different regenerative amplifiers reaching ＞0.5 J and ＞2 kW of average power. We then explore the scaling possibilities via multipass amplifiers and review the TRUMPF compact multipass module, a reliable and efficient tool for boosting ultrafast lasers to the multi-kilowatt level. As an outlook, we report on our non-linear pulse compression results aiming at obtaining sub-50 fs pulse durations from high-energy Yb-doped thin-disk sources.

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We present recent developments in high-power laser technology and applications at the HiLASE Centre. The efficient and stable operation of the diode-pumped solid-state laser system BIVOJ has been demonstrated, delivering 145 J pulses of 10 ns duration at a frequency of 10 Hz. This confirms the power scalability of the multi-slab cryogenic gas-cooled Yb:YAG amplifier technology. Additionally, the thin-disk laser platform PERLA® has been developed, capable of generating 1-ps pulses with an average power of up to 500 W at a wavelength of 1030 nm, with exceptional beam quality and power stability. Both laser systems are employed in various high-tech industrial applications such as laser shock peening, laser nano- processing, and material functionalization.

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In this paper, we review the use of high-power continuous-wave (CW) lasers for infrastructure maintenance on the ground and infrastructure construction in space. Steel structures, such as bridges, towers, and tanks require periodic repaint to prevent corrosion. This process involves surface treatment to remove old paint and rust, as well as salt deposits that contribute to corrosion. We developed a novel laser surface treatment using high-power CW lasers to provide the most effective method for salt removal. Recent research on CW laser surface treatment is reviewed in this article. In addition, standardization and education systems for construction workers and managers are discussed, as well as a brief analysis of the innovation process. The paper also discusses another potential use of high-power CW lasers, namely energy infrastructure in space and on the moon, related to the Artemis program proposed by NASA.

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This paper reviews the recent progress in the development of diode-pumped solid-state lasers (DPSSLs) with over 100 J pulse energy at a 10-Hz repetition rate and the feasibility of a 1 kJ-class DPSSL with a scaling concept on a helium gas-cooled multi-disk laser. The potential for contributions to laser fusion research using a 1 kJ-class DPSSL is also discussed. A construction and an operation of an integrated system, which consists of highly stable laser controlling, target production/supplying and plasma measurement/ diagnostics, based on a 1 kJ by 10-Hz DPSSL boost-up the level of such core technologies of laser fusion reactors to TRL 7 or more. These technologies will become common for various future applications for high energy and high-repetition rate lasers.

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We are developing and implementing advanced infrastructure inspection technology using joule-class pulsed lasers called “Laser hammering system (LHS)”. LHS is able to support inspectors by making conventional hammering inspections remote and digital. LHS has been already started trial operation in road tunnels, and improvement of inspection speed and distance are in progress. We have succeeded in a precise inspection of tunnel lining concrete at about half the speed of inspector and detection of the defect of a specimen 30 m away for the purpose of inspection of bridges.

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We demonstrated a 106 J, 10 Hz laser performance by an LD-pumped Yb:YAG ceramic laser with cryogenic helium gas cooling. To evaluate the laser amplifier’s performance with a helium gas cooling scheme, we are developing a 10 Hz operation with 250 J output. In our 106 J, 10 Hz output experiment, each laser amplifier was cooled with a helium gas mass-flow rate of 87 g/s for several kilowatts of pump power. As a result, a focusing property was affected by thermal wavefront distortion. We evaluated the temperature distribution of the laser medium to the flow rate of the cooling gas from experimental and thermal calculations.

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We have designed an X-ray crystal spectrometer with an elliptical configuration to monitor the X-ray spectrum of laser driven high atomic number plasmas. The resolution power (λ⁄Δλ) of the spectrometer is ＞500 in the 2500 ~ 3000 eV photon energy range, which enables us to observe the spectrum of Au Co-like (52+) and even more strongly ionized ions. This technique is helpful for diagnosing plasma generated during high-intensity high-contrast femtosecond laser driven high-Z ion acceleration experiments.

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