Classification and introduction of lasers

Fiber lasers

Fiber lasers are not new in industrial laser marking, CW fiber sources have been used for high-speed marking of integrated circuits (ICs) since 1998. In recent years, fiber lasers have made tremendous strides in terms of flexibility and overall performance, enabling a "fiber revolution" in the laser market.

With a monolithic, solid-state, fiber-to-fiber design that eliminates the need for alignment or adjustment using mirrors and optics, fiber lasers offer technical advantages that significantly improve the reliability and repeatability of laser processes. Fiber lasers also offer advantages in terms of integration and operation.

• Fiber lasers are compact and deliver energy through flexible fibers.
• Fiber lasers are more scalable and more efficient than any other laser technology, with Wall Plug Efficiency above 30%.
• Fiber lasers offer higher, more stable beam quality and excellent pulse-to-pulse stability, ensuring optimal repeatability over time, especially for critical marking processes.
• Q-switched fiber lasers offer long pulse widths (100 nanoseconds typical), making these light sources the first choice for metal marking in the automotive industry.
• Multi-band MOPA fiber lasers are available with emission pulse widths from 4 ns to 250 ns, ensuring excellent marking performance in terms of process optimization and repeatability.

Solid-state lasers

Diode-pumped solid-state lasers (DPSS) represent the most comprehensive technology in laser marking applications and remain the most flexible solution for generating green and UV laser radiation.

Solid-state laser emissions at 1064 nm can be efficiently converted to green emission at 532 nm (SHG second harmonic generation) and UV emission @355nm (THG third harmonic generation), enabling the engraving of almost any type of material with extremely high resolution and reduced heat-affected zone (HAZ). DPSSL is even ideal for heat-sensitive materials such as silicon wafers, WLCSP, thin memory cards, ICs, or highly reflective materials (copper, gold, silver).

• DPSS lasers are suitable for machining, non-destructive marking, processing high-tech, multi-layer, sensitive materials and components in the aerospace and high-tech industries.
• DPSS lasers offer the highest peak power and short pulse widths, providing cold working, even on stable and difficult-to-engrave materials.
• DPSS lasers are easy to repair.
• DPSS lasers can even be used for green and UV emission for low thermal footprint marking processes.
• DPSS lasers are the first choice for marking thermoplastic polymers in the electronics/electromechanical industry.

CO2 Lasers

CO2 optical devices, developed 50 years ago, already account for the largest share of the laser material processing market. Currently, CO2 photonics are the best solution for high thermal shock marking, with wavelengths up to 10 times longer than DPSS and fiber lasers. The wavelength (10600 nm) is very effective in typical packaging materials, such as:

• Paper, Corrugated Cardboard;
• Glass, Ceramics;
• Plastics, Polymers, Rubber;
• Paint, Coating Materials (Metal, Plastic PCB);