Intra-cavity dark pulse generation through synchronized sum-frequency mixing

A Nd:YVO4 laser operating at 1064 nm generating a stable mode-locked train of 10 ps-long dark pulses with a 211 MHz repetition rate is presented. The mode-locking relies on a periodic loss modulation produced by intra-cavity sum-frequency mixing with a synchronous bright-pulse train from a mode-locked femtosecond Yb:KYW laser at 1040 nm. A modulation depth of 9050 was achieved for the dark pulses, confirmed by cross-correlation measurements. The ultrafast loss modulation injects power into the Nd:YVO4 laser cavity modes beyond the laser gain bandwidth. At proper laser cavity length, the detuning interaction of these modes with the lasing modes leads to the generation of periodic ultra-fast transients at frequencies above 1.5 THz. (C) 2022 Optica Publishing Group

Automated summary

This paper presents an Nd:YVO4 laser operating at 1064 nm, which generates a stable mode-locked train of 10 ps-long dark pulses with a repetition rate of 211 MHz. The mode-locking is achieved through a periodic loss modulation produced by intra-cavity sum-frequency mixing with a synchronous bright-pulse train from a mode-locked femtosecond Yb:KYW laser at 1040 nm. The modulation depth of the dark pulses was measured to be 9050, confirmed by cross-correlation measurements. The ultrafast loss modulation injects power into the Nd:YVO4 laser cavity modes beyond the laser gain bandwidth, leading to the generation of periodic ultra-fast transients at frequencies above 1.5 THz when interacting with the lasing modes at the proper laser cavity length.