&gt;30 MW peak power from distributed face cooling tiny integrated laser

Zheng, Lihe; Kausas, Arvydas; Taira, Takunori

doi:10.1364/oe.27.030217

Cited by 23 publications

(4 citation statements)

References 27 publications

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“…Table 2 summarizes the LP conditions for the SBHS500 base metal and welded joint specimens. These conditions are based on those reported by Sano et al 5) , under which sufficiently large compressive RSs were produced on a 780-MPa-grade structural steel. LP was performed without any surface coating (sacrificial overlay) on the specimens using the portable LP device.…”

Section: Lp Conditionsmentioning

confidence: 99%

“…Furthermore, LP can be applied to objects with complicated surface structure by real-time control of the focal position of irradiated laser pulses. Furthermore, microchip laser technology can drastically reduce the size and weight of laser oscillators 5) . If a microchip laser could be used as the energy source for LP, the size of LP devices could be reduced, which would enable application of LP not only to production but also to on-site maintenance of existing infrastructure such as bridges in service.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Laser Peening on Fatigue Properties of Butt-Welded Joints with Angular Distortion

Kato,

Sakino,

Sano

et al. 2023

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY

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Laser peening (LP) is a well-established technique for introducing compressive residual stress (RS) near the surface of metal components to improve their high-cycle fatigue properties. In this study, butt-welded joint specimens of SBHS500 steel with angular distortion were prepared and treated with LP. X-ray diffraction showed that the maximum compressive RS over 400 MPa was introduced near the surface by applying LP with an irradiated pulse energy of 7.5 mJ, a spot size of 0.42 mm, and a pulse density of 800 pulses/mm 2 . The effect reached a depth of approximately 0.15 mm from the surface. The specimens were subjected to a uniaxial fatigue test with a stress ratio of 0.1 together with specimens without LP. The results showed that the fatigue life was prolonged by LP. However, in the stress range of 300 MPa, the detrimental effect of angular distortion predominates over the beneficial effect of LP, showing that the fatigue life extension by LP is not evident.

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Section: Lp Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Laser Peening on Fatigue Properties of Butt-Welded Joints with Angular Distortion

Kato,

Sakino,

Sano

et al. 2023

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY

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“…R. et al presented a microchip laser with 1.9 MW peak power, 500 Hz, 550 ps, and 532 nm [14], which was pumped into the Quasi-Continuous Wave (QCW) regime by a fiber-coupled 120 W, 808 nm laser diode. Zheng, L. et al reported a novel microchip laser using high thermal conductivity gain media with the beam of 21.5 mJ pulse energy, 10 Hz, 1064 nm, and an M 2 value between 10.7 and 11.8 [15]. Their research provided novel methods for the thermal restriction of microchip lasers, which would be expected in a high repetition rate.…”

Section: Introductionmentioning

confidence: 99%

High Repetition, TEM<sub>00</sub> mode, Compact Sub-Nanosecond 532nm Laser

Meng¹,

Wang²,

Zhou³

et al. 2022

Preprint

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As a critical transmitter, the compact 532 nm lasers operating on high repetition and narrow pulse widths have been used widely for airborne or space-borne laser active remote sensing. We developed a free space pumped TEM00 mode sub-nanosecond 532 nm laser that occupied a volume of less than 125 mm × 50 mm × 40 mm (0.25 liters). The fundamental 1064 nm laser consists of a passively Q-switched composite crystal microchip laser and an off-axis, two-pass power amplifier. The pump sources were two single-emitter semiconductor laser diodes (LD) of 808 nm with a maximum continuous wave (CW) power of 10 W each. The average power of fundamental 1064 nm laser was 1.26 W with the laser operating at 16 kHz repetition rates, and 857ps pulse widths. Since the beam distortion would be severe in microchip lasers in terms of the increase in heat load, for obtaining a high beam quality of 532 nm, the beam distortion was compensated by adjusting the distribution of pumping beam in our experiment of fundamental amplification. Furthermore, better than 0.6 W average power, 770 ps, beam quality of M2 ＜1.2, and 16 kHz pulse output at 532 nm was obtained by a Type I LiB3O5 (LBO) crystal in the critical phase matching (CPM) regime for second harmonic generation (SHG).

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“…2) One of the laser remote inspection methods is laser-induced breakdown spectroscopy (LIBS), an effective qualitative and quantitative method, 3) and the LIBS system has been developed and applied for these applications. [4][5][6][7][8][9][10][11][12][13][14][15][16] The LIBS system has also been developed for remote elemental analysis, 17) where a microchip laser (MCL) that can produce high pulse energy of MW level [18][19][20][21] to effectively generate intense plasma, and a ceramic composite with advantages such as scalability 22,23) were used. Owing to its potential application in a radiation environment, the radiation dose rate effects of gamma-ray on the developed system were measured at the dose rate up to 10 kGy h −1 .…”

Section: Introductionmentioning

confidence: 99%

Radiation robustness of laser ceramics and single crystal for microchip laser remote analysis

Tamura¹,

Ohba²,

Taira³

et al. 2022

Jpn. J. Appl. Phys.

Self Cite

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Laser pulse energy and pulse build-up time were measured during gamma irradiation at a dose rate of 150 Gy/h to evaluate the radiation-induced effects on a laser remote inspection system using ceramics and single crystal micro-chip laser. Results showed a time-dependent decrease in pulse energy and increase in pulse build-up time during irradiation. Both effects were larger for ceramics than for single crystal due to the amount of generated optical loss. The behaviours of pulse energy and build-up time with the increase in optical loss in the gain medium were simulated using rate equation calculations. The radiation effect on build-up time was larger than that on pulse energy for both specimens. Therefore, build-up time measurement is highly sensitive and effective for the evaluation of radiation effect generated in laser medium, especially for radiation robust specimens or at low radiation dose rate.

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>30 MW peak power from distributed face cooling tiny integrated laser

Cited by 23 publications

References 27 publications

Effect of Laser Peening on Fatigue Properties of Butt-Welded Joints with Angular Distortion

Effect of Laser Peening on Fatigue Properties of Butt-Welded Joints with Angular Distortion

High Repetition, TEM<sub>00</sub> mode, Compact Sub-Nanosecond 532nm Laser

Radiation robustness of laser ceramics and single crystal for microchip laser remote analysis

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