Diamond Meets Laser: The Processing Effects Of Different Laser Types Revealed

Diamond processing is difficult, and laser processing technology provides a solution. Applying laser processing technology to diamond processing can achieve efficient and high-precision processing of diamond. Today, let's take a look at the huge differences in the processing effects achieved by different laser beam types acting on the diamond surface.

 

Microsecond laser: wide pulse width, suitable for rough processing

Features and applications: Microsecond laser pulse width is wide, usually suitable for rough processing. For example, the author's research group used a Nd:YAG microsecond precision laser cutting machine with a wavelength of 1064nm to complete the processing of diamond heat sink structure.

 

Processing effect and impact: Its processing is accompanied by strong thermal damage. The peak power of the long-pulse microsecond laser is several kilowatts and the pulse duration is long, resulting in a deep heat-affected zone. For example, when processing diamond, the heat-affected zone can reach 6.8μm.

 

Nanosecond laser: occupies a large market share, and the processing is thermally destructive

Advantages and market conditions: Nanosecond laser has the advantages of good stability, low cost, and short processing time. It is widely used in enterprise production and currently occupies a large market share.

 

Thermal influence and related research: However, the nanosecond laser ablation process is thermally destructive to the sample, which is manifested macroscopically as a large heat-affected zone produced by the processing.

 

Nanjing University of Aeronautics and Astronautics has established a finite element simulation model of three-dimensional moving nanosecond pulse Gaussian laser ablation of single crystal diamond, and obtained the heat conduction and temperature distribution in the single crystal diamond under different scanning times;

 

Femtosecond laser: high processing accuracy, but low efficiency

High-precision processing characteristics: Femtosecond laser processing has high precision, can avoid the formation of heat-affected zone to the greatest extent within a very short pulse duration, accurately process the surface structure of diamond with minimal thermal damage, and is more suitable for fine processing of special diamond shapes. For example, femtosecond pulse laser can produce extremely high power density at a low average power, causing the C-C covalent bond in the diamond lattice to dissociate.

 

Efficiency and cost issues: However, its processing efficiency is low, and the expensive cost and maintenance cost of the femtosecond laser itself limit the promotion of processing methods. At present, most of the research on femtosecond laser processing of diamond remains in the laboratory stage. Compared with nanosecond lasers, femtosecond laser processing has higher surface quality, but the overall material removal rate is lower. For example, Han Yuan et al. calculated that the ablation rate of femtosecond lasers is two orders of magnitude lower than that of microsecond lasers.

 

Finally

Different types of lasers have their own advantages and disadvantages in diamond processing. Researchers are constantly exploring, striving to make laser technology play a greater role in the field of diamond processing and promote the development of related industries.