A TUNABLE FEMTOSECOND PULSES AMPLIFIER

We have designed a multipass amplifier combined with a folded prisms o ptical compressor that generates 80 fs light pulses tunable between 58 0 and 630 nm when using sulforhodamine B in water. The external energy source is a 20 Hz repetition rate, doubled Nd:YAG laser, delivering 8 ns pulses. A numerical model has been developed that describes the dy namics of gain saturation and amplified spontaneous emission growth in a multipass pulses amplifier. This model predicts a gain Q-switched b ehavior of the multipass amplifier for high pumping levels.