Page 124 - Lasers and IPLs in Medical/Aesthetic Applications v1.2
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Blink Reflex
Calibration
Coherence
Continuous Wave (CW)
Controlled Area Dermis
Diffuse Reflection
Divergence
Duty Cycle
Electromagnetic Spectrum
milliradian = 3.4 minutes-of-arc). For small angles where the cord is approximately equal to the arc, the beam divergence can be closely approximated by the ratio of the beam diameter divided by the distance (range) from the laser aperture.
An automatic reflex reaction to bright light entering the eye causing the eyelid to close. The average time for this reflex action is around 0.25 seconds. Note this only applies to visible light – there is no blink reflect to invisible laser light!
Calibration is a very important issue with lasers and IPL systems. Calibrating a system means that the numbers which appear on the screen actually make some sense in the real world. Many lasers/IPLs display numbers against energy/energy density or power which are meaningless. Unless these systems are properly calibrated using an external meter, then those numbers cannot relate to the real world. See more on calibrating your laser here... And here for IPL systems.
An expression describing light as waves which are in phase in both time (temporal coherence) and space (spatial coherence).
Constant, steady-state delivery of laser power. Any output longer than 0.25 seconds is considered to be ‘continuous’.
A designated area within which ‘Local Rules’ (see below) apply due to the potential hazards from a laser source.
Tissue which lies under the epidermis. It contains blood vessels, lymph vessels, nerves and consists of a collagen, elastin and reticulin matrix. Most tattoo pigment is found in the dermis.
A reflection from an ‘irregular’, or non-smooth surface such as a table-top or piece of clothing. This typically results in the light being reflected across a wide range of directions, unlike with ‘Specular Reflections’ (see below).
The increase in the diameter of the laser beam with distance from the exit aperture. The value gives the full angle at the point where the laser radiant exposure or irradiance is 1/e or 1/e2 of the maximum value, depending upon which criteria is used. Same as ‘Beam Divergence’ above.
The ratio of total "on" duration to total exposure duration for a repetitively pulsed laser. A duty cycle of 50% means that the laser beam is only for exactly half of the total duration.
The range of frequencies and wavelengths emitted by atomic systems. The total spectrum includes radio waves as well as short cosmic rays. Frequencies cover a range from 1 Hz to perhaps as high as 1020 Hz. See 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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