High average power, diffraction-limited picosecond output from a sapphire face-cooled Nd:YVO_4 slab amplifier

Abe, Matazô; Seki, Hiroki; Kowa, Maya; Sasaki, Yuta; Miyamoto, Katsuhiko; Omatsu, Takashige

doi:10.1364/josab.32.000714

Cited by 9 publications

(3 citation statements)

References 41 publications

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“…However, for fiber-based amplifiers, because the small mode areas and long interaction lengths for light propagating in optical fiber will cause pulse distortions and pulse break-up, complex chirped pulse amplification (CPA) configuration must be set up in most cases [15][16][17][18][19] , which will increase the complexity of systems. Recently, the partially pumped slab laser systems have been widely studied, due to the ability of circumventing nonlinearity by the short reaction distance between the light and gain matter [20][21][22][23][24][25][26][27] . These slab laser systems have provided a novel approach to realize CPA-free amplification with high power ultrafast pulses.…”

Section: Introductionmentioning

confidence: 99%

High pulse energy fiber/solid-slab hybrid picosecond pulse system for material processing on polycrystalline diamonds

Chen

Liu

Song

et al. 2018

High Pow Laser Sci Eng

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We demonstrate an all polarization-maintaining (PM) fiber mode-locked laser seeded, hybrid fiber/solid-slab picosecond pulse laser system which outputs 40 µJ, 10 ps pulses at the central wavelength of 1064 nm. The beam quality factors M 2 in the unstable and stable directions are 1.35 and 1.31, respectively. 15 µJ picosecond pulses at the central wavelength of 355 nm are generated through third harmonic generation (THG) by using two LiB 3 O 5 (LBO) crystals, in order to get better processing efficiency on polycrystalline diamonds. The high pulse energy and beam quality of these ultraviolet (UV) picosecond pulses are confirmed by latter experiments of material processing on polycrystalline diamonds. This scheme which combines the advantages of the all PM fiber mode-locked laser and the solid-slab amplifier enables compact, robust and chirped pulse amplification-free amplification with high power picosecond pulses.

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Section: Introductionmentioning

confidence: 99%

High pulse energy fiber/solid-slab hybrid picosecond pulse system for material processing on polycrystalline diamonds

Chen

Liu

Song

et al. 2018

High Pow Laser Sci Eng

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“…In the meantime, the generation of ultrafast vortex pulses in an optical fiber has been investigated as well. Omatsu et al demonstrated nano/pico-second vortex outputs from a large-mode-area optical fiber amplifier in combination with a 1064 nm solid-state master laser by applying appropriate stress on an amplifying fiber to couple the Gaussian mode to the ±1-order vortex mode, while selectively controlling the helical phase wave front [16]. Due to its complicated configuration, it was challenging to establish a theoretical model and further realize wavelength tunability.…”

Section: Introductionmentioning

confidence: 99%

Tunable-wavelength picosecond vortex generation in fiber and its application in frequency-doubled vortex

Zhang

Wei

Wang

et al. 2017

J. Opt.

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We present a method for tunable-wavelength picosecond vortex pulse generation by using an acoustically-induced fiber grating (AIFG). The AIFG-driven mode conversion characteristic was activated via a shear-mode piezoelectric transducer that excels in excitation efficiency of acoustic flexural wave and mechanical stability. The linearly-polarized ±1-order picosecond vortex pulse was experimentally generated via AIFG with a uniform coupling efficiency of ∼98.4% from the fundamental mode to the ±1-order vortex mode within the wavelength range 1540 nm ∼ 1560 nm. The topological charge and the linearly-polarized characteristic of the picosecond vortex pulse were verified by examination of the off-axial interference and the polarization angle-dependent intensity, respectively. Furthermore, the picosecond vortex pulse with wavelength tunability was input to a nonlinear BBO crystal to generate a frequency-doubled ±2-order vortex in the wavelength range 770 nm ∼ 780 nm. This technology provides a convenient apparatus for generating a picosecond vortex pulse and the frequency-doubled vortex with wavelength tunability.

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“…The optical transparency of sapphire is more than 85 % around a wavelength of 1 μm. Because of these excellent parameter values, sapphire has been used as an efficient heat-eliminating medium [13,14]. As Nd:glass slabs have low thermal conductivity, which is 0.83 W/m/K, one-side cooling method cannot satisfy the heat-removing requirement of a repetition rate amplifier.…”

Section: Introductionmentioning

confidence: 99%

Thermal-induced wavefront aberration in sapphire-cooled Nd:glass slab

Huang

et al. 2016

Appl. Phys. B

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and good beam quality, which can be achieved with diodepumped solid-state lasers (DPSSLs) [1]. DPSSLs can also provide good overlap efficiency between pumps and laser beams simultaneously. Current DPSSL development projects include mercury, with an output energy and repetition rate of 62 J and 10 Hz, respectively [2], LUCIA, with 6.6 J and 2 Hz [3], HALNA, with 8.4 J and 10 Hz [4], and dipole, with 6 J and 10 Hz [5].For efficient diode-pumped operation, the gain medium requires a long fluorescence lifetime in order to minimize the cost, few quantum defects to minimize the heat generation, and a high-gain cross section to extract energy efficiently. Nd:glass is a suitable material for high-energy DPSSL amplifiers as it exhibits long fluorescence lifetimes, acceptable gain cross sections, and few quantum defects. Furthermore, Nd:glass is available in large size with good optical quality, able to handle high pulse energies. However, phosphate glass has lower thermal conductivity and lower thermal shock resistance than other host materials, such as yttrium aluminum garnet (YAG). When operating at high repetition rates, the thermal problem is the main challenge for Nd:glass laser amplifier design, including thermal-induced wavefront aberration and depolarization loss; worst of all, it will lead to thermal fracture in the gain medium.Slab geometry can provide a larger cooling surface, although rod geometry is more frequently used for Nd:glass now [6,7]. Efficient heat removal is a key task for Nd:glass slab amplifier design. Current slab amplifiers with high repetition rates mainly use gas or liquid as a cooling medium [8,9]. However, these cooling systems may have negative effects on laser quality. As laser beams need to transmit through the cooling medium, solid materials may be a stable promising cooling strategy [10]. A team at the US Army Research Laboratory [11] and a Abstract We demonstrate for the first time a sapphirecooled Nd:glass composite assembly based on optical bonding of two thin sapphire plates to a Nd:glass slab for efficient heat removal. The distributions of temperature, stress, depolarization loss, and wavefront aberration were obtained by finite element analysis. The simulation results were verified experimentally. Although the heat generation rate was 4.5 W/cm 3 , the temperature increase was within 5.7 °C at the center of the sapphire surface, and the whole wavefront aberration was 1.21 λ (λ = 1053 nm). This demonstration opens up a viable path toward novel repetition rate Nd:glass laser amplifier designs with efficient doublesided room-temperature heat sinking on both sides of the slab.

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High average power, diffraction-limited picosecond output from a sapphire face-cooled Nd:YVO_4 slab amplifier

Cited by 9 publications

References 41 publications

High pulse energy fiber/solid-slab hybrid picosecond pulse system for material processing on polycrystalline diamonds

High pulse energy fiber/solid-slab hybrid picosecond pulse system for material processing on polycrystalline diamonds

Tunable-wavelength picosecond vortex generation in fiber and its application in frequency-doubled vortex

Thermal-induced wavefront aberration in sapphire-cooled Nd:glass slab

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