Passively Q-switched Nd:GdVO4 lasers with core–shell ZIF-8@ZIF-67 saturable absorber at 1 and 1.34 µm

In the current paper, the polyhedral ZIF-8@ZIF-67 nanomaterials were successfully synthesized, and the nonlinear optical features were measured through the open-aperture (OA) Z-scan technique. By employing the ZIF-8@ZIF-67 as a saturable absorber (SA), the passively Q-switched (PQS) Nd:GdVO4 lasers were demonstrated at 1064 and 1340 nm for the first time. From the 1 µm Q-switching operation, we achieved the shortest stable pulse of 85 ns under the incident excitation of 7.15 W, while the pulse repetition rate was 975 kHz. In the PQS laser at 1340 nm, the pulse width was measured as short as 79 ns with a pump level of 9.98 W, and the pulse repetition rate was 767 kHz. These results imply that the ZIF-8@ZIF-67 SA has huge advantages in the PQS laser with stable short pulse generation under the high excitations in the near-infrared (NIR) region.