We report an all-fiber, high-power, low-noise amplifier system seeded by an all-normal-dispersion-mode-locked Ybdoped fiber laser oscillator. Up to 10.6 W of average power is obtained at a repetition rate of 43 MHz with diffraction-limited beam quality. Amplified pulses are dechirped to sub-160-fs duration in a grating compressor. It is to our knowledge the first high-power source of femtosecond pulses with completely fiber-integrated amplification comprising commercially available components. Longterm stability is excellent. Short-term stability is characterized and an integrated laser intensity noise of <0.2% is reported. We also conclude that all-normal dispersion fiber oscillators are low-noise sources, suitable as seed for fiber amplifiers. Detailed numerical modeling of both pulse generation in the oscillator and propagation in the amplifier provide very good agreement with the experiments and allow us to identify its limitations.
Abstract:We propose and demonstrate the use of short pulsed fiber lasers in surface texturing using MHz-repetition-rate, microjoule-and sub-microjoule-energy pulses. Texturing of titanium-based (Ti6Al4V) dental implant surfaces is achieved using femtosecond, picosecond and (for comparison) nanosecond pulses with the aim of controlling attachment of human cells onto the surface. Femtosecond and picosecond pulses yield similar results in the creation of micron-scale textures with greatly reduced or no thermal heat effects, whereas nanosecond pulses result in strong thermal effects. Various surface textures are created with excellent uniformity and repeatability on a desired portion of the surface. The effects of the surface texturing on the attachment and proliferation of cells are characterized under cell culture conditions. Our data indicate that picosecond-pulsed laser modification can be utilized effectively in low-cost laser surface engineering of medical implants, where different areas on the surface can be made cell-attachment friendly or hostile through the use of different patterns. 192-203 (1997) Lett. 17, 733-737 (2004). 25. S. P. S. Porto, P. A. Fleury, and T. C. Damen, "Raman spectra of TiO2, MgF2, Zn F2, FeF2, and MnF2," Phys. Rev. 154, 522-526 (1967
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