Laser laser devices. The question of just how to assign credit for inventing the laser remains unresolved by historians. On May 16, 1960, Theodore H. Maiman operated the first functioning laser at Hughes Research Laboratories, Malibu, California, ahead of several research teams, including those of Townes, at Columbia University, Arthur Schawlow, at Bell Labs, and Gould, at the TRG (Technical Research Group) company. Maiman's functional laser used a solid-state flashlamp-pumped synthetic ruby crystal to produce red laser light, at 694 nanometers wavelength; however, the device only was capable of pulsed operation, because of its three-level pumping design scheme. Later that year,
Blue laser a longer-wave neodymium laser interposed between diode laser and doubler-crystal. The violet 405 nm laser (whether constructed from GaN or frequency-doubled GaAs laser diodes) is not in fact blue, but appears to the eye as violet, a color for which a human eye has a very limited sensitivity. When pointed at many white objects (such as white paper or white clothes which have been washed in certain washing powders) the visual appearance of the laser dot changes from violet to blue, due to fluorescence of brightening dyes. For display applications which must appear "true blue", a wavelength of 445–450 nm