
145
5
Lasers
5.1 The Development of LASERs
A class of light sources which are not used for general lighting but for a wide range of
other applications due to their unique characteristics is LASERs (Light Amplication
by Stimulated Emission of Radiation). LASERs were developed out of the technol-
ogy of MASERs (Microwave Amplication by Stimulated Emission of Radiation).
A concept for using lasers to create white light sources for general lighting is
illustrated in Figure5.1 but thus far it has not been deemed practical for development.
The emitted laser light is a spatially coherent (waves of the same frequency and
phase), narrow low-divergence ...