Radiant Energy - Answer Energy that is emitted, transferred or received. Measured in
Joules
Radiant Power - Answer Power emitted, transferred, or received in the form of radiation.
Measured in Watts
Irradiance - Answer Radiant power striking a surface divided by the area it is striking
W/cm2
Radiant Exposure - Answer Exposure over a particular area divided by the area it is
striking W/cm2
What does Laser stand for? -Answer Light Amplification by Stimulated Emission of
Radiation
What does a laser consist of? - Answer A Pumping System - What imparts energy to the
atoms of the lasing medium
An Optical Cavity - Contains the medium, has mirrors and provides
amplification/selection of photons
Laser medium - Can be solid state (ND:YAG), gaseous (HeNe, CO2, Ar,Kr), dye lasers
(Rhodamine 6G), and semiconductor
What are the four modes of laser operation? - Answer Continuous Wave - Beam time
over 0.25s
Single Pulsed -
Single Pulsed Q-switched - stored to increase power before release
Repetitively pulsed - Pulsed repetitively
, The different time modes provide different rates at which energy is delivered
What are three characteristics of a laser beam - Answer They are single wavelength
(monochromatic) that are tightly in phase with each other (coherent), and they are
tightly focused (collimated)
What are the two main US Government agencies involved in laser regulation? - Answer
OSHA and FDA
What AFI covers the Laser Radiation protection program - Answer AFI 48-139, we also
use ANSI 136.1
Class 1 laser - What is it? Cannot emit laser radiation capable of causing eye/skin injury.
A 1M is similar, but can cause damage if passed through magnifying optics.
These may be a higher class during maintenance/service
Class 2 laser - What is it? 2 - Staring into beam is an eye hazard. CW max 1mW
2M - Potentially hazardous if collecting optics are used;
CW max 500mW
These lasers are in the visible light spectrum 400-700nm
What is considered a class 3 laser? - Response 3R- Marginally unsafe for direct and
specular viewing.
CW max 5mW
3B - Unsafe for direct and specular viewing. Usually not unsafe for diffuse viewing. CW
max = 500mW
What is a class 4 laser? -Answer Exposure to direct and scattered beam can cause
eye/skin damage. Continuous wave power >0.5W. It is a hazard of fire.
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