Flexible picosecond burst generation in a mode-locked Nd:YVO4 laser with a compound cavity

Abstract

We present the generation of picosecond bursts with controllable pulse number in a passively mode-locked Nd:YVO4 laser with a compound cavity. This is the first time to use a compound cavity with additional SESAM to generate pulse burst. The device is constructed by inserting an HWP in the cavity, which reflects part of light in the main cavity into the auxiliary cavity and then the reflected beam is sent back after a delay in the auxiliary cavity. By controlling the power reflected into the main cavity from the auxiliary cavity, a series of bursts can be created with a selectable pulse number and adjustable temporal separation between the pulses. The temporal separation between two adjacent picosecond pulses in the burst can be adjusted by changing the length difference between two cavities. The temporal width of the burst can be adjusted from picosecond to nanosecond, and the repetition rate of the burst is the same as that in continuous wave mode-locked laser. The generation of the burst is presumably attributed to the temporal addition of laser pulses from the two cavities. This work provides a useful method for generating controllable picosecond laser burst.