Advances in High-Power, Ultrashort Pulse DPSSL Technologies at HiLASE

Smrž, Martin; Novák, Ondřej; Mužík, Jiří; Turčičová, Hana; Chyla, Michal; Nagisetty, Siva Sankar; Vyvlečka, Michal; Roskot, Lukas; Miura, Taisuke; Černohorská, Jitka; Sikocinski, Pawel; Chen, Liyuan; Huynh, Jaroslav; Severová, Patricie; Pranovich, Alina; Endo, Akira; Mocek, Tomáš

doi:10.3390/app7101016

Cited by 43 publications

(12 citation statements)

References 45 publications

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“…Considering the 1 kHz repetition rate of the used laser system, these throughputs can be scaled up in orders of magnitude together with the repetition rate. For example, HiLASE Perla C [15] operated at 100 kHz and a 3 mJ pulse energy may theoretically speed up those fabrication speeds toward 34 cm 2 /min and 2.06 m 2 /min. The important benefit of this large-beam interference approach is the scalability.…”

Section: Resultsmentioning

confidence: 99%

“…This is especially difficult to fulfil in the case of high-resolution micron scale structuring. Additionally, the increase in the average power of the ultrashort laser systems in recent years [15] were not reflected in the effectiveness of micro and nanoprocessing, as only a small percentage of the available laser power is used for processing to maintain high quality and avoid melting and thermal effects.…”

Section: Introductionmentioning

confidence: 99%

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Large-Beam Picosecond Interference Patterning of Metallic Substrates

et al. 2020

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In this paper, we introduce a method to efficiently use a high-energy pulsed 1.7 ps HiLASE Perla laser system for two beam interference patterning. The newly developed method of large-beam interference patterning permits the production of micro and sub-micron sized features on a treated surface with increased processing throughputs by enlarging the interference area. The limits for beam enlarging are explained and calculated for the used laser source. The formation of a variety of surface micro and nanostructures and their combinations are reported on stainless steel, invar, and tungsten with the maximum fabrication speed of 206 cm2/min. The wettability of selected hierarchical structures combining interference patterns with 2.6 µm periodicity and the nanoscale surface structures on top were analyzed showing superhydrophobic behavior with contact angles of 164°, 156°, and 150° in the case of stainless steel, invar, and tungsten, respectively.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Large-Beam Picosecond Interference Patterning of Metallic Substrates

et al. 2020

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“…The compressed pulse duration is between 1.8 ps and 1.9 ps and pulse energy is 6.5 mJ. The beam quality is high, with M 2 <1.3 [11,12].…”

Section: Methodsmentioning

confidence: 99%

Balancing the conversion efficiency and beam quality of second harmonic generation of a two-picosecond Yb:YAG thin-disk laser

et al. 2020

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In this work, the optimization of the second harmonic generation in an LiB3O5 crystal of the 1 kHz, 2 ps Yb:YAG laser is being investigated. Depending on the crystal thickness, an optimal intensity exists, above which the back-conversion process negatively affects the beam quality and pulse shape, while decreasing conversion efficiency. For a selected 2 mm thick frequency doubling crystal, the conversion efficiency of 80% at an optimal intensity of 120 GW cm−2 has been achieved, with output pulse duration of 1.3 ps and with beam quality of 1.4 and 1.6 in a horizontal and vertical direction, respectively, which is only slightly worse than the beam quality at a fundamental frequency.

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“…make Yb:YAG suitable for the generation of picosecond and femtosecond pulses. Its relatively low quantum defect and good thermal properties permit the scaling of output power to the kW level [3,4]. The gain medium is usually pumped at a broad absorption line with a peak at 941 nm and a full width at half maximum (FWHM) of approximately 10 nm [5].…”

Section: Investigation Of Spectrally-dependent Phonon Relaxation Mech...mentioning

confidence: 99%

Investigation of spectrally-dependent phonon relaxation mechanism in Yb:YAG gain media and its consequences for thin disk laser performance

Severová¹,

Nagisetty²,

Chyla³

et al. 2020

Laser Phys.

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Nonlinear phonon relaxation in Yb:YAG gain media has previously been investigated, and a hypothesis correlating photo-induced free electrons and heat generation in crystals pumped at a wavelength of 940 nm was established (Brandt et al 2011 Appl. Phys. B 102 765–8). Later, we demonstrated efficient suppression of nonlinear phonon relaxation by zero-phonon line (ZPL) pumping of Yb:YAG (969 nm). However, no hypothesis has yet been tested that correlates the heat load and the free electrons in Yb:YAG media. We investigate, both theoretically and experimentally, the behaviour of an Yb:YAG slab pumped by a high-power laser diode at a conventional broadband line (absorption maximum at 941 nm) and a ZPL (absorption maximum at 969 nm), and we compare the generated photocurrent, temperature, and absorbed pump power for those two pump wavelengths. Although the hypothesis established by Brandt et al (2011 Appl. Phys. B 102 765–8) was not confirmed, and the measured photocurrent was identical for the two pump wavelengths, our measurement contributes to the knowledge of the inner processes in Yb:YAG active media. In the following steps we characterized an Yb:YAG thin disk laser, measured the spectrally-resolved absorption and disk surface temperature, and optimised our predictive model of thin disk behaviour. All the experimental and theoretical results are reported.

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Advances in High-Power, Ultrashort Pulse DPSSL Technologies at HiLASE

Cited by 43 publications

References 45 publications

Large-Beam Picosecond Interference Patterning of Metallic Substrates

Large-Beam Picosecond Interference Patterning of Metallic Substrates

Balancing the conversion efficiency and beam quality of second harmonic generation of a two-picosecond Yb:YAG thin-disk laser

Investigation of spectrally-dependent phonon relaxation mechanism in Yb:YAG gain media and its consequences for thin disk laser performance

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