Electro-optic mode locking of an erbium:YAG laser with a rf resonance transformer

An Er:YAG laser at a wavelength of 2.94µm was simultaneously Q switched and actively mode locked with LiNbO(3) as an electro-optic modulator. The modulation crystal was integrated into a specially designed resonance transformer capable of generating a rf voltage of 3 kV(pp)at a frequency of 160 MHz. Mode-locked pulses with a calculated pulse width ≤230 ps were obtained within a Q-switched envelope of 200 ns by applying 16 W of electrical driving power to the resonance transformer during a period of 20 µ;s.