Page 55 - Lasers and IPLs in Medical/Aesthetic Applications v1.2
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Chapter 1 – Fundamentals of Medical/Aesthetic Lasers and IPLs v1.2
Picosecond Lasers
In December 2012 the world’s first commercial picosecond laser was launched for tattoo removal by Cynosure. This device utilised a technique to shorten the output pulse energy duration from nanosecond (billionths of a second) to just under 1 nanosecond. These shorter pulses were around 550 to 750 picoseconds, which is 0.55 to 0.75 nanoseconds.
So, you can see that they are only around one tenth of the standard 5 to 10 ns pulsewidths of the more established Q-switched lasers.
What does this actually mean in terms of treatments?
Well, the shorter pulse means that there is less time for the heat energy to flow away from the tattoo inks particles. This results in higher peak temperatures on the surfaces of those particles.
Unfortunately, there is a lot of nonsense spouted about the benefits of picosecond lasers! This usually comes from ill-informed sales-people. These systems are usually expensive, so the sales-people will tell you anything to make a sale!
Mike wrote a blog post about this very subject, comparing nanosecond with picosecond treatments of tattoos...
Figure 28: A tattoo
  Many will claim that they can removal “all ink colours” – this is simply NOT TRUE! As we will see in “Chapter 2 – Laser Tattoo Removal”, the ability to treat ink colour depends mainly on the wavelength, not the pulsewidth!!
Many will claim that they can remove tattoos “in far fewer treatment numbers” – this was a big claim in the early days, to make these expensive systems more attractive to buyers. However, the reality is it depends on the individual tattoos. Some fade quickly, others take longer. There is some evidence that picosecond lasers may accelerate this process a little.
We will discuss this type of laser in much more details in Chapter 2.
Often we hear people describing picosecond lasers as ‘faster’ than the older, nanosecond devices. This is not correct. Their pulses are shorter – not faster!!
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Chapter 1 LEVEL A Fundamentals of Lasers/IPLs
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