Although both CO2 lasers and excimer lasers are mentioned, and these two lasers still have great value in material processing, the current discussion will focus on lasers with a wavelength of 2 μm to about 300 nm. This also excludes quadruple-frequency laser pointer, but such lasers are more useful before picosecond and femtosecond lasers are commercialized. And based on reliability issues, they are not used unless absolutely necessary (such as excimer lasers).
Shows some characteristics of the three wavelengths discussed in this article. In short, ultraviolet photons are more expensive and have lower power than infrared photons, but can achieve smaller, cleaner features, and more accurate material removal, but slower than using infrared photons. Visible wavelengths are used in required applications, such as the back processing of transparent materials or the removal of indium tin oxide (ITO), but in view of eye safety issues, other alternatives are usually considered first.
Diode pumped solid-state lasers were first introduced into the industrial environment in the late 1990s. At the time, the first such laser had a low output power of only a few watts, and its wavelength was 355 nm. Before diode pumping, laser pumping was used to obtain laser light, but such lasers were very unreliable. At the time, the cost of a few watts of nanosecond ultraviolet light exceeded $100,000.
Subsequently, the market for nanosecond lasers became more and more mature, and these lasers are now also available from many different manufacturers (providing infrared, visible, and ultraviolet wavelengths). The price of nanosecond lasers with 10W ultraviolet output power is low. It’s $50,000. In most cases, the pulse duration of these lasers is in the range of tens to hundreds of nanoseconds.
A picosecond laser is a green laser pointer with a pulse width of picoseconds. It has the characteristics of picosecond ultra-short pulse width, adjustable repetition frequency and high pulse energy. The picosecond laser was first introduced commercially in 2005, and the ultrafast laser leader company (now acquired by American coherent companies) was the main market participant at the time. Of course, it did not take too long to witness the influx of many other players into the market-now, whether it is a research laser or an industrial laser, there are many options.