Page 178 - Chapter 3 - An Introduction to Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 1st Edition
Power Densities
A simple way to directly compare lasers and IPLs is to look at their power density outputs. The power density combines the fluence with the pulsewidth, but does not consider the wavelength. Let’s look at the power output for IPLs and lasers typically used in LHR:
Device
Power density (W/cm2)
IPL
2000 - 4000
Diode
200 - 5000
Alexandrite
2500 - 25000
Nd:YAG
3000 - 6000
Table 41 – Comparison of power densities from hair removal devices
IPL Systems:
Typically, we use around 20 to 50 J/cm2 in 10ms pulsewidths – this is a power output of 2000 – 5000 Watts/cm2 of power density.
Parameter
Laser
IPL
Wavelength
Single
400-1400 nm
Fluence
Up to 60 J/cm2 (diodes can go higher)
Up to 50 J/cm2 typically
Pulsewidth
Up to 100 ms
Up to 100 ms (or longer!)
Spot size
Up to 18 mm
12 x 12 mm (diodes)
Up to 40 x 15 mm
Table 42 – Typical Laser and IPL parameters
Note that some systems will exceed the above parameters, but the above are the most typical used in today’s technology.
Diode Lasers:
From discussions with users and data sheets from laser suppliers, the power densities output by these systems during treatments range from around 200 W/cm2 to 5000 W/cm2. However, currently there are many different systems available on the market with a very wide range of power outputs from 500W up to over 5000W. These tend to be using wavelengths such as 800 or 810nm, but there are some systems which output a 900nm wavelength.
________________________________________________________________________ 178 Chapter 3 Laser/IPL Hair Removal
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