Red diode-pumped alexandrite regenerative amplifier generating up to 78  μJ and down to 260  fs pulses

We present the first red diode-pumped alexandrite ultrafast amplifier, as well as the first red diode-pumped femtosecond alexandrite master oscillator power amplifier system. We achieved amplification of 90 fs pulses from nJ to μJ pulse energies and compression of the amplified pulses to 260 fs at 133 kHz, with a pulse energy of 2.5 μJ. A maximum pulse energy of 78 μJ is achieved at a repetition rate of 2 kHz. The amplifier output beam quality was good, with measured M 2 = 1.35.