High Power, Low Threshold 630 Nm Lasers

Visible semiconductor laser diodes are receiving increasing attention for various uses. Important applications of visible semiconductor lasers include laser pointers, solid state laser pumping, printing, medicine, bar code scanning, and optical data storage. While devices emitting near 680 nm are relatively mature, there is interest in obtaining emission wavelengths in the 630 nm band. Benefits of shorter wavelength emission include increased visibility to the human eye and reduced spot size. The apparent brightness to the human eye is increased by a factor of 15 by moving from 680 nm to 630 nm. Additionally, since emission at a shorter wavelengths leads to a smaller diffraction limited spot size, short wavelength semiconductor lasers will yield higher storage densities in optical data storage.