Here is described a simple process to 'put a voice on a sunbeam' and transmit it over a distance. It is a fascinating example of amplitude modulation of light using sound vibrations. It then describes how the modulated light is detected...

At this site from the Nobel e-Museum, you can read about the scientific work of Lord Rayleigh (1842-1919 CE). This article includes information on his education and experiments with light and sound waves.