Page 94 - Lasers and IPLs in Medical/Aesthetic Applications v1.2
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Chapter 1 – Fundamentals of Medical/Aesthetic Lasers and IPLs v1.2
 If you are interested, the ‘1/e’ expression comes from the Beer-Lambert equation which can be used to calculate the change in intensity of light energy as it propagates through a substance.
We will discuss this in more detail in a later Chapter.
Short pulses versus long pulses – effect on heating
  Target tissue
Heat conduction during a laser/IPL pulse (same energy in both cases)
     Short pulse – higher temperature Long pulse – lower temperature
Figure 53: Shorter laser pulses result in less thermal conduction during the pulse. This results in higher temperatures at the absorbing sites. Longer pulsewidths allow for heat energy to conduct away from the absorbing site during the pulse resulting in lower peak temperatures.
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Chapter 1 LEVEL A Fundamentals of Lasers/IPLs
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