Overview: Surface-enhanced Raman scattering (SERS) affords a rapid, highly sensitive, and nondestructive approach for label-free and fingerprint diagnosis of a wide range of chemicals. This technique has been applied in explosives detection, pre-cancer diagnosis, food safety, and forensic analysis, where a small number of hazardous substances can seriously affect health of human beings. Thus, it is of great significance to prepare high-performance SERS sensors. In general, the signal intensity of SERS is determined by the following three factors: 1) The enhancement effect of surface nanostructure on local electric fields; 2) The number of molecules to be detected in hot spots; 3) Performance of the Raman spectrometer. Therefore, in order to achieve high-performance SERS detection of trace molecules, current research focuses on how to increase the density of hot spots and the number of analyte molecules in the detection area. An ultrafast laser has an ultra-short pulse width and ultra-high peak power, so it can interact with the majority of materials with high processing accuracy and excellent controllability. Meanwhile, it can rapidly construct a variety of large-area micro/nano-structures on material surfaces based on facile digital programming strategies. In addition, combined with multi-beam parallel fast scanning technology, low-cost and high-efficiency machining can be realized without a special requirement for the machining environment. Based on the above advantages, the ultrafast laser has become one of the important means for the fabrication of micro/nano-structures. This is important for the commercial preparation of high-performance SERS sensors. In this paper, we focus on two aspects to introduce the ultrafast laser preparation of high-performance SERS sensors, including how to increase the density of hot spots and the number of analyte molecules in the detection region. Ultrafast lasers can prepare micro/nano-structures with local field enhancement effects by both "bottom-up" and "top-down" processing strategies. The first is based on the "bottom-up" principle, where the reduction, deposition or polymerization of atoms, molecules or other nanoparticles is controlled by ultrafast lasers to achieve additive manufacturing of micro/nano-structures. The other is based on the "top-down" principle, where materials are removed by the ultrafast laser ablation to rapidly achieve hierarchical micro/nanostructures. These structures provide abundant active hot spots for SERS detection. In particular, the superhydrophobic surfaces prepared by the ultrafast laser are one of the most effective methods to achieve the enrichment of analyte molecules. Raman scattering can be excited more effectively by enriched molecules, which is conducive to obtaining higher detection limits and realizing ultra-trace detection. Finally, a prospect for the development of laser-prepared SERS substrates is provided.

Overview: With the development of industry, laser fabrication has become one of the important technologies for welding, cutting, surface processing, and other advanced manufacturing areas. At the same time, the pursuit of structures miniaturization, devices integration, and high precision has put forward more stringent requirements for laser fabrication technologies. Due to the advantages of stable mechanical and chemical properties and unique photoelectric properties, hard and brittle materials have been widely used in aerospace, the photoelectric industry, et al. Laser fabrication is an ideal technology for hard and brittle materials processing due to its high precision, high energy, and non-contact properties. In order to achieve the removal of hard and brittle materials, high laser energy is usually required, resulting in low fabrication accuracy and poor surface quality. As an improved laser processing method, liquidassisted laser fabrication can effectively improve fabrication accuracy and surface quality. The processing characteristics and material removal principles of three different liquid-assisted laser processing technologies are summarized in this review. According to the different functions of the medium through which the laser penetrates and the kinds of liquid, liquid-assisted laser fabrication technology can be divided into Laser ablation in liquid (LAL), laser-induced backside wet etching (LIBWE), and etching-assisted laser modification (EALM). The auxiliary liquid of Laser ablation in liquid is mostly water, which mainly plays the role of cooling and removing debris. The auxiliary liquids used by laser-induced backside wet etching include organic solvents, acid-base solutions, inorganic salts, and other liquids, which play different roles according to different liquids. The etching-assisted laser modification mainly uses an acid or alkaline solution as an auxiliary liquid to remove laser-modified materials. Different methods and auxiliary liquids have different mechanisms in the methods. Therefore, almost any material can be processed by choosing suitable methods and auxiliary liquids, including photosensitive glass, silicon crystal, sapphire, and other transparent hard brittle materials. Here, we summarize the fabrication technologies and fabrication parameters for different materials. The development and applications of liquid-assisted laser fabrication technologies in the fields of micro-optical components, microfluidic devices, and drilling and cutting are introduced. Finally, the challenges of the technology are discussed.

Carnivorous plants, for instance, Dionaea muscipula and Nepenthes pitcher plant, inspired the innovation of advanced stimuli-responsive actuators and lubricant-infused slippery surfaces, respectively. However, hybrid bionic devices that combine the active and passive prey trapping capabilities of the two kinds of carnivorous plants remain a challenge. Herein, we report a moisture responsive shape-morphing slippery surface that enables both moisture responsive shape-morphing and oil-lubricated water repellency for simultaneous active- and passive-droplet manipulation. The moisture deformable slippery surface is prepared by creating biomimetic microstructures on graphene oxide (GO) membrane via femtosecond laser direct writing and subsequent lubricating with a thin layer of oil on the laser structured reduced GO (LRGO) surface. The integration of a lubricant-infused slippery surface with an LRGO/GO bilayer actuator endows the actuator with droplet sliding ability and promotes the moisture deformation performance due to oil-enhanced water repellency of the inert layer (LRGO). Based on the shape-morphing slippery surface, we prepared a series of proof-of-concept actuators, including a moisture-response Dionaea muscipula actuator, a smart frog tongue, and a smart flower, demonstrating their versatility for active/passive trapping, droplet manipulation, and sensing.Carnivorous plants, for instance, Dionaea muscipula and Nepenthes pitcher plant, inspired the innovation of advanced stimuli-responsive actuators and lubricant-infused slippery surfaces, respectively. However, hybrid bionic devices that combine the active and passive prey trapping capabilities of the two kinds of carnivorous plants remain a challenge. Herein, we report a moisture responsive shape-morphing slippery surface that enables both moisture responsive shape-morphing and oil-lubricated water repellency for simultaneous active- and passive-droplet manipulation. The moisture deformable slippery surface is prepared by creating biomimetic microstructures on graphene oxide (GO) membrane via femtosecond laser direct writing and subsequent lubricating with a thin layer of oil on the laser structured reduced GO (LRGO) surface. The integration of a lubricant-infused slippery surface with an LRGO/GO bilayer actuator endows the actuator with droplet sliding ability and promotes the moisture deformation performance due to oil-enhanced water repellency of the inert layer (LRGO). Based on the shape-morphing slippery surface, we prepared a series of proof-of-concept actuators, including a moisture-response Dionaea muscipula actuator, a smart frog tongue, and a smart flower, demonstrating their versatility for active/passive trapping, droplet manipulation, and sensing.

传统的长焦深光束生成器件，诸如空间光调制器和正负透镜组合，存在光学元件尺寸较大、难以与微纳光学系统集成等问题，发展一种长焦深光束生成方法并制备一种结构简单、尺寸紧凑且成像质量良好的长焦深光束器件尤为重要。提出了一种利用连续立方相位板调制来产生长焦深光束的方法，通过飞秒激光直写技术制备了高尺寸精度（直径为108 μm，高1.1 μm）的相位板，实现了可调控的焦距长度（50~150 μm）和焦深（100~600 μm），并且对相位板进行光学测试，展示了其长聚焦能力和成像能力。该器件可用于高性能集成光学系统、微纳光学制造等领域。

超快激光在金属、电介质和半导体表面制备周期性纳米结构可以有效地改变材料的物化性质，如光学、电学、亲疏水性等。周期性纳米条纹取向通常依赖于激光的偏振，因此利用径向偏振的飞秒激光能够制备不同弯曲度的周期性纳米条纹。通过分析柱透镜聚焦的径向偏振光光场具有随空间变化的偏振方向，实验上获得了柱透镜聚焦的径向光场在不同位置诱导周期性纳米结构的形貌特征。随后利用5 mm的狭缝分离矢量光场中的各向异性偏振态来获得不同弯曲角度条纹的大面积制备。结果表明，利用这种方法在ZnO表面获得了弯曲可控的深亚波长（190～380 nm）周期条纹结构，并且成功制备了弯曲角度从0°到165°的大面积周期性纳米条纹。