Fig. 1. Q-switched ring TDFL schematic.

Fig. 2. Pulse energy as a function of pump power at 100 Hz.

Fig. 3. Pulse width as a function of pump power for a cavity length of 6.68 m.

Fig. 4. Typical train of pulses and pulse shape at a repetition rate of 100 Hz: (a) a pulse train and (b) a single pulse.

Fig. 5. Pulse width of the TDFL for different cavity lengths as a function of the output pulse energy.

Fig. 6. Typical spectra of the output laser at 70 and 150 μJ, respectively.