Modulation and single-spike switching of a diode-pumped Er3+:LiYF4 laser at 2.8 μm

An Er3+:YLF laser at 2.8 mu m pumped with two polarization-coupled diode lasers is built. The emission properties of the laser are studied. The threshold is 107 mW and the slope efficiency is 33%. The laser output is modulated by either chopping the pump beam or by chopping the resonator mode. Single-spike switching using a rotating mirror is demonstrated for the first time in bulk material lasers at 2.8 @m. Single spikes (pulse duration: 200-500 ns) are emitted with repetition rates up to 137 Hz. The temporal shape of the spikes is nearly Gaussian, Pulse duration and repetition rates are ideal for micro surgical applications. Rotating-mirror Q-switching was employed as other standard switching devices, such as acoustooptic or electrooptic modulators that were presently available to us introduce losses to the cavity that cannot be compensated with the highest achievable gain in our system.