Page 261 - Chapter 3 - Laser/IPL Hair Removal

Focal Length
Focal Point
Frequency
Helium-Neon Laser (HeNe)
Hertz (Hz)
Near-Infrared Radiation (NIR)
Intensity
Irradiance
Joule (J) Joule/cm2 Laser
Laser Class
Distance between the centre of a lens and the point on the optical axis to which parallel rays of light are converged by the laser.
That distance from the focusing lens where the laser beam has the smallest diameter.
The number of light waves passing a fixed point in a given unit of time, or the number of complete vibrations in that period of time.
A laser in which the active medium is a mixture of helium and neon. Its wavelength is usually in the visible range. Used widely for alignment, recording, printing, and measuring.
Unit of frequency in the International System of Units (SI), abbreviated Hz; replaces ‘cps’ for cycles per second.
Invisible electromagnetic radiation with wavelengths which lie within the range of 0.7 to 1000 microns.
This also known as ‘Irradiance’ and is a measure of the light power falling on a surface per unit area – the power in a laser spot on the skin/tissue surface. It is measured in Watts/cm2. See more here...
Radiant power incident per unit area upon a surface, expressed in watts-per- centimetre- squared (W/cm2). Often referred to as the ‘Power Density’.
A unit of energy (1 watt-second) used to describe the rate of energy delivery. It is equal to 1 watt-second or 0.239 calorie.
A unit of radiant exposure (energy density or fluence) used in measuring the amount of energy incident upon a unit area.
An acronym for light amplification by stimulated emission of radiation. A laser is a cavity, with mirrors at the ends, filled with material such as crystal, glass, liquid, gas or dye. A device which produces an intense beam of light with the unique properties of coherence, collimation and monochromaticity.
An indication of the beam hazard level of a laser or laser system during normal operation or the determination thereof. The hazard level of a laser or laser system is represented by a number or a numbered capital letter. The laser classifications are Class 1, Class 1M, Class 1C, Class 2, Class 2M, Class 3R, Class 3B and Class 4. In general, the potential beam hazard level increases in the same order.
Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
________________________________________________________________________ 261 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
© The Laser-IPL Guys, 2025