Experimental Study On All Solid State Q-Switched Pulse Laser Based On Graphene Quantum Dots

All-solid-state passive Q-switched lasers have attracted much attention due to their wide application in the fields of micromachining,laser ranging,remote sensing,microsurgery,and nonlinear frequency conversion.Compared with active Q-switched lasers,laser systems using saturable absorbing materials have the advantages of small size,simplicity,and low cost.It is reported that semiconductor materials such as Ga As,semiconductor saturable absorption mirrors?SESAMs?,graphene?Gr?,and molybdenum disulfide?Mo S₂?,represented by new"graphene-like"two-dimensional materials have been used as Q-switching elements to generate laser pulse.In recent years,quantum dots?QDs?have become a new and attractive nonlinear optical material due to their relatively wide absorption spectrum,lower saturation flux,faster recovery time,and lower unsaturated loss.It has a vital application in ultra-short pulse lasers.This paper mainly studies the passive Q-switching characteristics of graphene quantum dots?GQDs?in all-solid-state lasers:?1?The graphene quantum dot?GQDs?solution was prepared by hydrothermal method and the excellent performance of GQDs SA was obtained.The microstructure and photoelectric performance of GQDs SA were characterized by Raman,XRD,TEM and Z-scan.to assess its quality.The modulation depth of GQDs SA was 6.2%and the saturation intensity was 19.6MW/cm² measured by a nonlinear test.?2?The LD pumped Nd:YVO₄ crystal all-solid-state pulsed laser system was studied,and the design and construction of the adjustment of each cavity mirror were simulated and designed.A 1063.5 nm Q-switched laser output based on GQDs SA was realized.The Q-switched pulse repetition frequency was 1.64 MHz The width is 200 ns,and the maximum pulse energy and pulse peak power are 0.44?J and 2.43 W,respectively.?3?A 532 nm all-solid-state pulsed laser system was designed.Based on the laser frequency doubling theory,a 531.8 nm Q-switched pulse laser output based on GQDs SA was realized;the Q-switched pulse repetition frequency was 1.83 MHz,the pulse width was 180 ns,and the maximum pulse energy and pulse peak power 0.44?J and 2.43 W respectively.