Laser used for laser drilling

Lasers primarily used for laser drilling applications are CO2, Nd:YAG, excimer, and copper vapor lasers (CVL).

CO2 Lasers

Pulsed-mode CO2 lasers can be used for drilling both metals and non-metals. However, especially when drilling small and/or deep holes in metals, Nd:YAG lasers are more suitable because of their better energy coupling at shorter wavelengths (1.06µm for Nd:YAG versus 10.6µm for CO2), as well as higher peak power and pulse repetition rates. Medium- and low-power CO2 lasers are mainly used for non-metal drilling applications and ceramic scribing (i.e., a series of holes).

Nd:YAG Lasers

Nd:YAG lasers (fundamental wavelength 1.06µm) are the primary lasers used for laser drilling of metals, with their main application undoubtedly being the drilling of cooling holes in aerospace engine components (turbine blades, combustion chambers, etc.). By using nonlinear crystals (providing frequency doubling), i.e., shortening the laser wavelength, Nd:YAG lasers can also operate in the visible or ultraviolet (UV) portions of the spectrum.

Excimer Lasers

Excimer lasers emit laser light in the ultraviolet portion of the spectrum and are mainly used for precision drilling, profiling, and micromachining, such as microvia drilling in printed circuit boards/printed wiring boards in the microelectronics industry. They are also best suited for producing arrays of holes in one or a few steps. Due to their low pulse repetition rates, excimer lasers are less suitable for use on metals.

Copper Vapor Lasers (CVL)

The basic CVL produces laser light in the visible portion of the spectrum (green and yellow), and CVLs are inherently pulsed at very high repetition rates. Like excimer lasers, CVLs are used for precision drilling, profiling, and micromachining. CVLs can be used on most materials, including metals.