首次采用氧化石墨烯可饱和吸收体作为锁模启动元件在Tm,Ho∶CaYAlO4激光器中实现了稳定的被动调Q锁模运转。在3%输出耦合镜下, Tm,Ho∶CaYAlO4固体激光器获得了最低为293 mW的连续光出光阈值。在腔内引入氧化石墨烯可饱和吸收体后, 当吸收抽运功率增大到1 859 mW时, Tm,Ho∶CaYAlO4激光器进入稳定的调Q锁模运转状态。当抽运功率达到3 W时, 获得中心波长为2 089 nm、斜效率为10.1%、对应最大输出功率为213 mW的被动调Q锁模脉冲, 重复频率为100 MHz, 调Q包络中锁模脉冲的调制深度接近100%。

Employing graphene oxide as a saturable absorber, we experimentally demonstrated a passively Q-switched mode-locked (QML) operation of a Tm,Ho∶CaYAlO4 bulk laser. In this case, the absorbed threshold power of Tm,Ho∶CaYAlO4 bulk laser was measured as 293 mW by using a 3% output coupler. When the absorption pumping power reached 1 859 mW, it entered a stable Q-switched mode-locked operation state. And when the pumping power reached 3 W, the corresponding maximum output power is 213 mW, corresponding to a slope efficiency of 10.1%, the central wavelength of 2 089 nm, the repetition frequency of 100 MHz, and the modulation depth being close to 100%.