We review recent advances in high power semiconductor lasers including increased spectral brightness, increased spatial brightness, and reduced cost architectures at wavelengths from the near infrared to the eye-safe regime. Data are presented which demonstrate both edge emitter devices and high power surface emitting 2-dimensional arrays with internal gratings to narrow and stabilize the spectrum. Diodes with multimode high spatial brightness and high power single mode performance in the 808 and 976nm regime are described, and advances in high power bars at eye-safe wavelengths are presented. These devices have the potential to dramatically improve diode pumped systems and enable new direct diode applications.Keywords: Diode, laser, semiconductor, bar, stack, array IntroductionConventional edge emitting high power diode lasers have been used in printing, defense, medical, and materials processing because of their compactness, low cost per Watt-hour, and excellent electrical to optical efficiency. While these high power diode lasers are broadly accepted for low brightness applications, their use has been limited due to the low spatial and spectral brightness performance, costly power scaling, and limited range of emission wavelengths. In particular, the spatial beam quality from high power diode lasers is a factor of 10-20 times lower than non-diode lasers such as gas, solid state, or fiber laser counterparts. Moreover, the spectral output of conventional diode lasers is typically an order of magnitude wider than these non-diode systems and is inadequate for efficient wavelength conversion or other pumping applications requiring narrow linewidth. Power scaling is achieved by combining the output of individually mounted bars, the cost of which scales linearly or superlinearly with power. Finally, the range of wavelengths available commercially from high power conventional diode lasers has mainly been limited to broadband emission in the near infrared regime of 800 nm to 980 nm.

We review recent advances in high power semiconductor lasers including increased spectral brightness, increased spatial brightness, and reduced cost architectures at wavelengths from the near infrared to the eye-safe regime. Data are presented which demonstrate both edge emitter devices and high power surface emitting 2-dimensional arrays with internal gratings to narrow and stabilize the spectrum. Diodes with multimode high spatial brightness and high power single mode performance in the 808 and 976nm regime are described, and advances in high power bars at eye-safe wavelengths are presented. These devices have the potential to dramatically improve diode pumped systems and enable new direct diode applications.Keywords: Diode, laser, semiconductor, bar, stack, array IntroductionConventional edge emitting high power diode lasers have been used in printing, defense, medical, and materials processing because of their compactness, low cost per Watt-hour, and excellent electrical to optical efficiency. While these high power diode lasers are broadly accepted for low brightness applications, their use has been limited due to the low spatial and spectral brightness performance, costly power scaling, and limited range of emission wavelengths. In particular, the spatial beam quality from high power diode lasers is a factor of 10-20 times lower than non-diode lasers such as gas, solid state, or fiber laser counterparts. Moreover, the spectral output of conventional diode lasers is typically an order of magnitude wider than these non-diode systems and is inadequate for efficient wavelength conversion or other pumping applications requiring narrow linewidth. Power scaling is achieved by combining the output of individually mounted bars, the cost of which scales linearly or superlinearly with power. Finally, the range of wavelengths available commercially from high power conventional diode lasers has mainly been limited to broadband emission in the near infrared regime of 800 nm to 980 nm.