LIGHT IS SO fundamental to human existence that it was taken for granted in ancient time and not specifically listed in the classical elements of the universe.
We now understand of course, that light is electromagnetic radiation in a frequency range that is visible to the human eye. In 1917 physicist Albert Einstein predicted that light could also be produced by a process that he named ‘Stimulated Emission’.
Light produced in this way would be spatially coherent, collimated and monochromatic, meaning that it could be focused into a narrow beam capable of transmitting energy over distance and concentrating it in a small area. Enter the laser.
Powerful tools
For 30 years laser was like a ‘solution waiting for a problem’ as it had found no real purpose, until the theory of holography (that could only be realised with laser light) was developed.
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