Fig. 1. Schematic of hybrid fiber/solid-state femtosecond laser amplifier. PCF, photonic crystal fiber; TFP, thin film polarizer; PC, Pockels cell; DM, dichroic mirror; LD, laser diode.

Fig. 2. (a) Spectra of the oscillator (blue) and the PCF pre-amplifier (black). (b) Autocorrelation traces of the dechirped pulse from the oscillator (red), the pre-chirped pulse from the oscillator (blue), and the pre-chirped pulse from the pre-amplifier (black).

Fig. 3. (a) 10 dB spectral bandwidth (left) and average power (right) versus round-trip number. (b) Evolution of the spectrum during amplification. (c) Output pulse spectra and (d) autocorrelation traces of dechirped pulses with an optical gate time of 300 ns (green), 400 ns (blue), 500 ns (red), and 1000 ns (black).

Fig. 4. Average output power (left) and pulse energy (right) versus different repetition rates and beam profiles at 60 kHz (inset).

Fig. 5. (a) Spectra of injected seed source (black) and amplified pulses for $N_p$ polarization (blue) and $N_m$ polarization (red). (b) Autocorrelation traces of output pulses for $N_p$ polarization (blue) and $N_m$ polarization (red).