Abstract
We demonstrate an all polarization-maintaining (PM) fiber mode-locked laser seeded, hybrid fiber/solid-slab picosecond pulse laser system which outputs $40~\unicode[STIX]{x03BC}\text{J}$, 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. $15~\unicode[STIX]{x03BC}\text{J}$ picosecond pulses at the central wavelength of 355 nm are generated through third harmonic generation (THG) by using two $\text{LiB}_{3}\text{O}_{5}$ (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.
Highlights
High power, high repetition rate pulse lasers with neardiffraction-limited beam quality have made significant contributions in many applications such as X-ray generation[1], attosecond pulses generation[2] and material processing[3–7]
Due to the normal dispersion and self-phase modulation (SPM) effect in the pre-amplifier and pulse picker, the full width at half-maximum (FWHM) spectral width is broadened to ∼0.75 nm, which is acceptable for the Nd:YVO4 amplifier
The all PM fiber mode-locked laser is operated at the central wavelength of 1064 nm, and outputs 75 mW, 9.09 ps at a low repetition rate of 30.7 MHz
Summary
High repetition rate pulse lasers with neardiffraction-limited beam quality have made significant contributions in many applications such as X-ray generation[1], attosecond pulses generation[2] and material processing[3–7]. All polarization-maintaining (PM) fiber mode-locked lasers have been confirmed as robust, compact and alignmentfree light sources with the output pulse duration of less than 10 ps[8–13]. Due to the fact that lights are always trapped in the PM fiber without any free space optical devices, these structures are less sensitive to external temperature and stress perturbations. As a result, this kind of mode-locked laser shows much more robustness and less output states, compared to traditional NLPR mode-locked lasers, which is an ideal alternative to Q-switch laser in material processing applications
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