## 1 Introduction  
Diamond is widely used in a variety of applications, including precision cutting tools, optical devices for microelectronic devices, and biological fields, due to its excellent properties, such as high hardness, high strength, high thermal conductivity, extremely high electron mobility, excellent optical properties, stable chemical properties, and good biocompatibility. As a result, there is a growing need for diamond to be processed with extreme precision [1; 2; 3]. Currently, grinding, chemical-mechanical, thermochemical, ion beam, and laser processing are the primary procedures utilized to extract diamonds. The removal of materials occurs during the classic grinding process by friction between the workpiece and diamond particles fused to the grinding wheel. Low removal efficiency and significant grinding wheel wear issues with diamond grinding because of the small hardness differential between the workpiece and the grinding wheel [4]. Chemical and mechanical action are used in chemical-mechanical machining to remove materials. Although it can produce a superior machining surface, grinding is more efficient. It only applies to the machining of shaped workpieces and has stringent standards for the workplace [5]. Although the processing efficiency of thermochemical processing has significantly increased, this technology still requires further optimization due to its low stability, high cost, and sophisticated equipment as well as its sensitivity to temperature and ambient gas [6]. The ion beam sputtering technique can produce finely machined surfaces, but its promotion and use are constrained by its expensive equipment and slow material removal rate [7]. Because of its low cost, straightforward procedure, and high etching rate, laser processing is commonly employed in the production of diamonds. A femtosecond laser differs from conventional lasers in that it has a short pulse duration and high instantaneous power. Due to its small heat--affected zone, high accuracy, and lack of shock wave cracks in the processing area, femtosecond laser processing is widely employed in precision and special machining applications [8; 9]. In recent years, there has been an increase in the use of femtosecond laser processing technology in the bulk processing, surface microstructure processing, and surface modification of various materials, including metal materials. This is due to its unique machining mechanism, with high-quality machining results that can be used for the machining of non--metallic organic materials [10; 11; 12], polymeric substances [13], and semiconductor materials [14], and excellent properties such as high machining accuracy [15; 16; 17]. Due to the femtosecond laser machining technique's extremely high spatial resolution, femtosecond laser machining of diamond and other super-hard materials has great efficiency, good processing quality, and high flexibility. In [PERSON] et al. 's study [18], although CVD diamond microtools can be made by precision grinding, they do not have high machining capacity. Laser machining is one of the most important methods for diamond machining because it offers the advantages of precision directivity, capability, and a small heat-impacted zone [19; 20]. Diamond arrays were brazed onto a stainless-steel substrate by [PERSON] et al. [21] using 40 fs and 5 ns laser pulses. The test results showed that the femtosecond laser's threshold for processing diamond is lower than that of a nanosecond laser because of its thermal inhibition. In a study by a team from Keio University in Japan [22], an adhesive-free polycrystalline diamond micro ball end milling cutter was successfully developed using a circularly polarized femtosecond pulse laser. A study team at Hunan University investigated the mechanisms of the femtosecond laser etching of single-crystal diamond materials and the use of a micro-texture array in the end face of a single crystal diamond grinding tool [23; 24].