Timeline of United States inventions (1946–91) of the United States Geological Survey. 1960 Gas laser A gas laser is a laser in which an electric current is discharged through a gas to produce light. The first gas laser, the Helium-neon, was invented by William R. Bennett, Don Herriott, and Ali Javan in 1960. The first continuous visible gas laser, operating at 632.8 nm in the red, was invented by A. D. White and J. D. Rigden in 1962. 1961 Spreadsheet (electronic) 1961 Wearable computer 1961 Frozen carbonated beverage 1961 Biofeedback 1962 Communications satellite 1962 Chimney starter 1962 Light-emitting diode A light-emitting-diode (LED) is a semiconductor diode
Light-emitting diode have enabled making devices with ever-shorter wavelengths, emitting light in a variety of colors. LEDs are usually built on an n-type substrate, with an electrode attached to the p-type layer deposited on its surface. P-type substrates, while less common, occur as well. Many commercial LEDs, especially GaN/InGaN, also use sapphire substrate. Bare uncoated semiconductors such as silicon exhibit a very high refractive index relative to open air, which prevents passage of photons arriving at sharp angles relative to the air-contacting surface of the semiconductor due to total internal reflection. This property affects both the light-emission efficiency of LEDs as well