Page 207 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
If we added two of these arrays together, we would have a total power output of 3000W with a maximum fluence of 75 J/cm2.
To answer the first question, a 3000W laser might be one of three things:
1. It might be 3 x 1000W arrays, or,
2. it might be 2 x 1500W arrays,
3. or it might even be a single 3000W array!
These will also have different spot sizes (3cm2, 2cm2 and 1cm2 respectively – assuming the above conditions).
Conclusion
It’s all very confusing!! In a nutshell, increasing the power output of a diode laser can result in either a larger area on the skin surface with the same maximum fluence as with the lower powered units, or, a higher available fluence in the same spot size area.
What ultimately matters is that you have sufficient fluence to reach the deepest targets. It’s the fluence that matters most – insufficient fluence will always lead to poor results, regardless of the power.
Diode Lasers - Average Power vs Peak Power
We‘ve noticed a few laser companies promoting their systems on the basis of the “power”. With quotes like “the most powerful laser on the planet” and similar nonsense, they are trying to ‘hoodwink’ potential buyers into buying their devices.
They are, of course, playing on people’s ignorance. Most people don’t really understand what “power” is. Or how it relates to lasers and skin treatments. So, here’s the lowdown.
A bit of physics...
Firstly, any cheap Q-switched laser is hugely more ‘powerful’ than any diode laser! Picosecond lasers are even more powerful. So, what does it actually mean?
Basic physics tells us that ‘power’ is simply how quickly or slowly energy is delivered. So, the shorter the time some energy is delivered, the higher the power. If you fire 10 Joules of energy at the skin in 1 millisecond, then the peak power of that pulse is simply 10/0.001 which is 10,000 Watts. (Note that 1 ms = 0.001 seconds).
________________________________________________________________________ 207 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
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