Applied Physics and Materials Science

Photonics, Optics and Lasers

Light Amplification by Stimulated Emission of Radiation (Laser). The first laser device was a pulsed ruby laser, demonstrated by Theodore H. Maiman in the 1960s at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. In the same year, the first gas laser, a helium–neon laser and the first laser diode were made. Semiconductor lasers, that are predominantly laser diodes, that are electrically or optically pumped, efficiently generating very high output powers, but typically with poor beam quality, or low powers with very good spatial properties for application in media players, or pulses for example for telecom applications with very high pulse repetition rates. Special types include quantum cascade lasers for mid-infrared light and surface-emitting semiconductor lasers, the latter also being suitable for pulse generation with high powers.