Light-emitting diode into a lower energy level and releases energy in the form of a photon. The wavelength of the light emitted, and thus its color, depends on the band gap energy of the materials forming the "p-n junction". In silicon or germanium diodes, the electrons and holes usually recombine by a "non-radiative transition", which produces no optical emission, because these are indirect band gap materials. The materials used for the LED have a direct band gap with energies corresponding to near-infrared, visible, or near-ultraviolet light. LED development began with infrared and red devices made with gallium arsenide. Advances in materials science
Whitefish Point Light had two unevenly spaced eclipses, and two flashes within every 20 second period. Putting aside questions of nostalgia, aesthetics, or appreciation for the engineering of a bygone era (as exemplified by the Fresnel lens), this iteration of lighthouse illumination was itself incredibly effective, and an endangered remnant of another bygone era. The station was automated in 1971. In 2011, the U.S. Coast Guard Local Notice to Mariners reported reduced intensity of the Whitefish Point light from June 7, 2011 until August 16, 2011, when the DCB-224 Series Carlisle & Finch aerobeacon lens was changed to a light-emitting diode (LED) lantern