Femtosecond(fs) laser-induced micro-nano structures on metal and semiconductor surfaces have been extensively studied. However, one-step fs laser-induced graphene (LIG) on wood surface is a research hotspot in recent years. The conversion of wood to graphene takes two steps: the wood is carbonized by a pre-pulse of fs laser radiation, and the carbonized wood is further converted into graphene by a subsequent pulse of fs laser radiation. Traditional high-power continuous wavelength laser can only rely on the accumulation of thermal effect to achieve the carbonization of wood, and wood cannot be further converted into graphene. Fs laser induced graphene is related to the repetition rate of fs laser. Studies show that graphene can be induced at a certain laser power and at any scanning speed when the repetition rate reaches 500 kHz. The main difference is the quality of graphene. Interestingly, the ability of fs lasers to induce graphene in wood is also related to the material composition of induced the wood itself. Because wood is rich in lignin, and the aromatic molecules in lignin are induced into graphene by fs laser. Therefore, lignin-rich materials such as wood, coconut shells and paper, can be induced to produce graphene by fs laser. In this paper, a fs laser with a central wavelength of 355 nm and a repetition rate of 500 kHz was used to successfully induce graphene on wood. The G, D and 2D peaks were observed by Raman spectroscopy. Graphene induced on the wood can be used to PH meters and heat switches.

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