Malus, Etienne

The simplest experiment on polarization was made much later (in 1808) hy the French engineer Etienne Louis Malus, who was in Napoleon s army. Fie reflected a heam of light at the surfaces of two unsilvered pieces of glass (see Fig. 3.9) and observed that when the two reflections are in the same plane, a high proportion of the light incident on the second mirror (M2) is reflected. If the mirror M2 is turned so that the second reflection is directed out of the plane of the paper, the... 

Light oscillatiug in one plane only is called polarized light. This name was given it in 1808 by a French physicist, Etienne Louis Malus (1775-1812). At that time, the wave theory had not yet been accepted, and Malus had a notion that light consisted of particles with north and south poles, and that in polarized light, all the poles were lined in the same direction. This theory quickly vanished, but the expression remained and is still used. 

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