What is Laser Ablation?

Laser ablation is the process by which layers are removed from solid metals and industrial compounds using a laser beam for ultimate precision. The beam will irradiate the surface, meaning that it has been exposed to radiation.

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Laser ablation is being used here for the thin film removal of oxide from titanium

Laser ablation is used for a variety of different industries and applications and is one of the many uses of SPI Laser’s Fiber Laser range. Below we explore laser ablation in more depth, looking at what it is and why it is used.

What is the laser ablation process?

Laser ablation works by focusing a laser onto a substrate to a remove material that is on its surface. The amount that is removed depends on the intensity, pulse length, and wavelength of the laser, as well as the material itself. The area absorbs the laser that is being directed on it, thereby breaking down the chemical bonds within the area.

With a low level of laser flux, the material being focused upon is absorbed by the laser’s energy and then changes to a gaseous state. With a higher level of laser flux, the material that is being focused upon will usually be converted to plasma. It is possible to undergo the laser ablation process with both a pulsed fiber laser and a continuous wave laser, although the former is the more common method due to the high level of laser intensity.

Laser ablation has many benefits over more traditional methods of processes, such as with thin film removal, whereby alternative solutions have to undergo a multi-step process which is costly, time-consuming and inflexible, as well as having risks for the environment. Laser ablation is a much more efficient, reliable and cost-effective method.

What uses does laser ablation have?

Laser ablation has many different uses, particularly as the whole process is undergone with minimal excess heat being transferred to the surrounding area of the material being used. This means that the process will have little to no effect on the parts of the material that you don’t want it to, and so laser ablation is great for a wide range of materials, including plastic, metal, ceramic, and even biological tissue. With the advanced nature of fiber lasers, you can focus on a very small, specific spot to produce your desired results.

Laser ablation can also be used to determine the presence and concentration levels of a particular chemical or material on a surface. This is achieved by generating bright plasma on the surface, and then analysing this plasma to see what is present there. This is a much more environmentally-friendly process for determining chemical analysis, as opposed to more traditional methods such as using toxic acid solutions.

Finally, laser ablation can be used to deposit film on a surface, so as to produce things like Nanomaterials or to fabricate superconducting materials. This can also be used for the micro-structuring of an object, whereby the structuring of a larger object can be seen.

Laser ablation is also useful for viewing the micro-structuring of an object

Laser ablation is also useful for viewing the micro-structuring of an object

What factors need to be considered for laser ablation?

The success and efficiency of the laser ablation process depend on a number of factors. These are:

Wavelength

The wavelength needs to be selected carefully with a minimum absorption depth. This is so that there is a high energy deposition within a small volume, resulting in a quick and efficient laser ablation.

Pulse Duration

It is better to use shorter pulse durations so as to perform at maximum peak power and to minimise the thermal damage that is inflicted on the surrounding area, although this is already greatly reduced due to the precise nature of the laser ablation process.

Pulse Repetition Rate

The pulse repetition rate needs to be high enough so that the heat caused by laser ablation is maintained and is not left any time to cool. This will result in a more successful ablation as energy waste will be reduced.

Beam Quality

Your laser beam needs to be of sufficient quality to perform the laser ablation process successfully. The quality of the beam will be determined by its brightness, its focus ability, and its homogeneity. The beam size will also need to be controlled so that you don’t ablate too large an area.

Application areas for laser ablation

Due to the precise, accurate and environmentally-friendly nature of laser ablation, it is used in many different application areas and industries. Its ability to remove thin film has particular benefits for the electronics and semiconductor industries, and it has also found uses for other industries such as medical, automotive and ship-building. It has understandably become the preferred solution for many manufacturing processes.

Contacting SPI about laser ablation

If you’re interested to find out more on how laser ablation could be useful for you, and what application areas in can be incorporated into, don’t hesitate to get in touch with one of our team through the contact page or contact us on +44(0)1489 779 696, or by email at sales@spilasers.com.

 

Image Credit: Seed Magazine

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