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 as the light-absorption efficiency of photovoltaic cells. The refractive index of silicon is set at 3.96 (at 590 nm), while air's refractive index is set at 1.0002926. In general, a flat-surface uncoated LED semiconductor chip emits light only perpendicular to the semiconductor's surface, and a few degrees to the side, in a cone shape referred to as the "light cone", "cone of light", or the "escape cone". The maximum angle of incidence is referred to as the critical angle. When the critical angle is exceeded, photons no longer escape the semiconductor but are, instead, reflected internally inside the semiconductor crystal