Hannover 2010 – wissenschaftliches Programm

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SYLA: Symposium 50 Years of Lasers

SYLA 1: 50 Years of Lasers I

SYLA 1.1: Hauptvortrag

Mittwoch, 10. März 2010, 14:00–14:30, E 415

How the laser happend — •Herbert Welling — Leibniz Universität Hannover

After the realization of masers, microwave oscillators with an entirely new concept of amplification -namely by stimulated emission of radiation, scientists around Charles Townes at Columbia University and Arthur Schawlow at Bell Telephone Laboratories started to think how the new concept could be transferred to oscillators in the infrared and even visible region to generate there coherent radiation. However it turned out that a tremendous amount of research had to be done to achieve in an atomic or molecular ensemble a population inversion and to develop optical resonators with adequate size and Q-values.

The first laser was realized in July 1960 at the Hughes Aircraft Research Laboratories by T. H. Maiman using ruby as the active material; his achievement came entirely as a surprise, but it was not an accidental discovery. The laser is just a new light source but his radiation shows superiority in coherence in space and time and offers the potential of high intensity. After Maimans invention in 1960 in many famous laboratories all over the world research was intensified to find new laser materials, to find atomic and molecular systems suited to generate population inversion, and theoretical and experimental work was concentrated to understand the spatial and temporal coherence of the laser radiation.