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,
Photonic laser thruster can only occur for a finite range of optical frequencies. The gain bandwidth is approximately the width of this frequency range. For example, the gain bandwidth of the YAG laser system with the laser wavelength in the order of 1,000 nm is in the order of 0.6 nm, ~ 0.06% of the wavelength. For an order of magnitude estimation, it can be assumed that a thruster utilizing the YAG laser system will be limited by the gain bandwidth to the first order, i.e., its theoretical maximum spacecraft velocity is ~ (180 km/s), 0.06% of the light velocity, c=3x10 m/s. To