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Chapter 1 – Fundamentals of Medical/Aesthetic Lasers and IPLs v1.2
taken as 7 mm). The AEL is dependent on the laser Class and are defined in the EN 60825- 1/A2 Standard.
The AEL limits are based on the emitted energy/power from a laser, while the MPE limits are based on the radiative energy received by the eye or the skin (either directly from the laser aperture or by reflection/refraction). In other words: AELs are based on devices while MPEs are based on people!
Laser Classifications – International Standards
LASER stands for Light Amplification by the Stimulated Emission of Radiation but is defined in EN 60825-1:2014 as 'any device that can be made to produce or amplify electromagnetic radiation in the wavelength range from 180nm to 1mm primarily by the process of controlled stimulated emission’.
The higher the class of laser the greater the optical hazard it presents. The classification is based upon the measured radiation through a given aperture at a set distance (see section 9 of EN 60825-1:2014), and AELs (accessible emission levels) have been set for each class of laser (see Tables 4-9, pages 43-48, EN 60825-1: 2014). In the descriptions below the lasers cover the full wavelength range unless a restriction is stated.
Class 1 Lasers (AEL < 0.039 mW)
These are normally safe either because of their inherently low power or because they are within a totally enclosed system where access to higher levels of laser radiation is not possible during normal operation. Such lasers output a maximum of 0.039 mW (milliwatts) of visible light such that they will not generate any tissue damage even if viewed over long periods of time.
For all Class 1 lasers the maximum radiant power of the accessible beam is always below the MPE for that laser.
If access panels of a totally enclosed system are removed for servicing etc then the laser product is no longer Class 1 and the precautions applicable to the embedded laser must be applied until the panels are replaced.
Class 1M Lasers (AEL < 0.039 mW)
These are laser products, emitting in the wavelength range 302.5nm to 4000nm, whose total output is in excess of that normally permitted for Class 1 laser products but because of their diverging beams or very low power density do not pose a hazard in normal use and comply with the measurement conditions for a Class 1M product. However, they may be
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Chapter 1 LEVEL A Fundamentals of Lasers/IPLs
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