Page 77 - An Introduction to Laser Tattoo Removal

Chapter 2 – Fundamentals of Laser Tattoo Removal v1.0
Wavelength
Currently there are only four wavelengths used routinely for laser tattoo removal – 532, 694, 755 and 1064nm. There have been a couple of other wavelengths tried, but these have not been adopted widely.
All of these, except 532nm, are red or near infra-red (IR) wavelengths. 532nm is green.
Frequency-double Nd:YAG 532 nm
Ruby Alex 694nm 755nm
Nd:YAG 1064nm
400 nm 530 nm 578 nm Wavelength
700 nm
>700 nm
Figure 36: Wavelengths, colours and laser wavelengths
The red/IR wavelengths are particularly useful as they can penetrate into the dermis very well. The 532nm green light does not penetrate so deeply, which can determine how useful it is. How do these wavelengths compare?
All of these wavelengths can be absorbed by a wide range of coloured tattoo inks – some better than others. However, as has been described in this animation, it is impossible to know just how well these wavelengths might be absorbed – simply because we cannot know what the ink colours are actually composed of! In addition, the physical constituents of the inks can have a significant effect on their absorption properties.
Likewise, all of these wavelengths are strongly reflected by white pigments such as titanium dioxide.
The Nd:YAG laser - 1064/532 wavelengths
The neodymium:YAG laser uses the neodymium crystal, inside the laser cavity, to generate a 1064nm wavelength. It can only generate 1064nm. However, some of this energy can be
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Chapter 2 LEVEL A Laser Tattoo Removal
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Infra-red 
Visible spectrum