A 36 nJ-15.5 MHz extended-cavity Ti:sapphire oscillator

Summary form only given. Ultrafast Ti:sapphire lasers are widely-used sources of ultrashort pulses in the near infrared region of the spectrum. The "standard" Ti:sapphire oscillator has a repetition rate of between 70 and 100 MHz, with average output powers of about 500 mW when pumped by 5 W from an argon-ion laser. Although the intracavity pulse energy (/spl sim/40 nJ) is sufficient to facilitate the nonlinear modelocking process, the 5-6 nJ output energy is somewhat lower than is ideal for a number of nonlinear-optics and ultrafast chemistry investigations. The energy per pulse from the laser can be increased by reducing the output repetition rate. This can done using cavity-dumping; however, a much simpler and less expensive method was recently demonstrated. The output repetition rate depends on the cavity length. Simply moving the end-mirrors farther apart increases the alignment sensitivity and decreases the stability range of the cavity. However, by introducing a 1:1 telescope in the laser cavity, the optical configuration of the laser can remain unchanged, preserving the high reliability of these lasers while significantly lowering the repetition rate.