By using an atmospheric-pressure chemical vapor deposition (APCVD) method with a C 2 H 2 carbon source, seven-layer graphene films as saturable absorbers are fabricated and transferred to an anti-reflective mirror of 1064 nm wavelength range. Based on this transmission-type graphene saturable absorber mirror (GSAM), a continuous wave (CW) passively mode-locked femtosecond green laser is achieved by 808 nm laser diode (LD) end-pumped Nd:YVO 4 crystal and type-I critical phase-matched LBO crystal intracavity frequency doubling for the first time. Stable ultrashort green laser pulses as short as 374 fs are measured with a repetition rate of 71.4 MHz and an average output power of 117 mW at a central wavelength of 531.7 nm.

The band structure, electronic, magnetic, and optical properties of g-SiC monolayers doped with alkaline earth metals (Be, Mg, Ca, Sr, and Ba) are calculated by means of first principles based on density functional theory. Although the intrinsic g-SiC monolayer is nonmagnetic, it shows magnetic properties after doping with alkaline earth metals. The magnetic moments are, in the order of the above-named dopants, 1.583 μ B, 1817 μ B, 2.000 μ B, 2.000 μ B, and 2.000 μ B. Charge transfer and the net spin charge occur mainly between the dopant atom and surrounding C atoms. The results show that the conductivity of g-SiC can be greatly improved by doping with alkaline earth metals, a technique that can be applied to the field of semiconductor spintronics. High absorption peaks in the ultraviolet indicate that the material has potential applications in UV optoelectronic devices.

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