Development of Cavity-Dumped Ti : sapphire Femtosecond Laser and its Amplifier

点击翻译按钮获取中文摘要

We have developed an intra-cavity dumped femtosecond Ti : sapphire laser system and its multi-pass amplifier to obtain a moderately high energy short pulse, enough to perform third order optical nonlinear experiment in liquid solutions. Currently, commercially available femtosecond Ti : sapphire laser systems are either (1)Ti : sapphire oscillator (general price = 18,000,000 yen), which yields a pulse with an energy of 4 nJ/pulse, or (2)Ti : sapphire oscillator and its amplifier (general price = 50,000,000 yen), which yields a pulse with an energy of 1 mJ/pulse. In order to perform experiment with a short pulse in chemical systems such as transient absorption or photon echo, we need a pulse with an energy around mJ/pulse to sub mJ/pulse. Therefore, a new short pulse laser system is desirable to get s moderately high energy pulse. In this research project we here calculated stability of oscillation for the cavity-dumped Ti : sapphire laser by the ABCD matrix formalism. We have investigated both the five-mirror configuration and six-mirror configuration theoretically and experimentally. The cavity dumper laser produces a pulse width of 13 fs and energy of 67 nJ/pulse at 4 MHz. Currently, a multi-pass (six-pass) amplifier with a Ti : sapphire crystal is being designed and constructed to get a higher energy pulse. The purpose of this amplifier is to get a pulse with an energy more than sub microJ/pulse at 20 kHz. We are also writing a manual to construct this laser system and are planning to distribute it to public.