1) Japanese invention 
A blue laser is a laser that emits electromagnetic radiation at a wavelength of between 360 and 480 nanometres, which the human eye sees as blue or violet. Blue beams are produced by gas lasers using Helium-Cadmium at 441.6 nm, and Argon-ion at 458 and 488 nm. Semiconductor laser diode lasers with blue beams are typically based on gallium(III) nit...