sentences:  The key major accomplishment was the 1962 observation of nearly 100% internal efficiency in the conversion of electron-hole pairs to photons in GaAs semiconductor devices at MIT Lincoln Laboratory, RCA Laboratories, and Texas Instruments, Inc., shortly thereafter followed by the demonstration of the first diode laser by General Electric and IBM.The new semiconductor laser devices operated only at cryogenic temperatures (typically that of liquid nitrogen, that is, at 77°K or –196 °C).For practical use, it would be necessary to demonstrate diode laser action, continuous-wave, at room temperature.