Page 128 - Lasers and IPLs in Medical/Aesthetic Applications v1.2
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Pulse Duration
Pulsed Laser Q-Switch
Radiant Exposure
When the heated tissues reach a certain temperature (typically around 100°C) the local tissue water will reach boiling point. At this point the water will begin to turn onto steam and cause an ablative process within the tissue cells. This results in those cells ‘flying off’ the tissue.
One picosecond is 10-12 seconds or 0.000000000001s. Some modern-day aesthetic/medical lasers output energy pulses in the range 350 to 900 ps. Picosecond lasers were introduced commercially for tattoo removal. See how they compare with the older, Q-switched lasers here.
Plume, or smoke, generated by lasers or IPLs when applied to human tissue (in this instance). Recent research indicates that plume from laser/IPL skin treatments may be potentially hazardous to laser operators. Appropriate protective measures should, therefore, be taken routinely. See Mike’s article on this topic here.
Also known as ‘photo-sensitivity’ – some people have skin which reacts adversely to intense light. All potential clients should be asked if they are aware of such a condition as they will not respond well to this treatment.
The amount of light emitted by a laser handpiece over time is measured as power. The ‘peak power’ is the maximum power emitted during this pulse. Measured in Watts which are ‘Joules per second’. See more here...
The pulse duration is simply the length of the pulse of light (measured in milliseconds or nanoseconds in many aesthetic/medical systems). It is also called the pulsewidth or pulse length. See more here...
Laser which delivers energy in the form of a single or train of pulses, typically of duration less than 0.25 seconds.
A Q-switch is an optical device designed to force the laser energy within a pumping chamber to be released in a fraction of the normal emission time, typically nanoseconds. Q-switched may be ‘active’ or ‘passive’. Read more here...
The total energy per unit area incident upon a given surface. It is used to express exposure to pulsed laser radiation in units of J/cm2. It is commonly referred to as ‘Energy Density’ or ‘Fluence’ in many skin-laser centres.
In the context of optics, electromagnetic energy is released; the process of releasing electromagnetic energy results in radiation. We live in a bath of radiation constantly, but are unaware of most of it. Read more here...
Chapter 1 – Fundamentals of Medical/Aesthetic Lasers and IPLs v1.2
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Chapter 1 LEVEL A Fundamentals of Lasers/IPLs
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