Paul Rudy

High-Efficiency Blue and True-Green-Emitting Laser Diodes Based on Non-c-Plane Oriented GaN Substrates

Using non-c-plane bulk GaN substrates, we demonstrate continuous-wave single-mode blue-emitting laser diodes operating with over 23% wall plug efficiency and over 750 mW output power, which represent the highest values reported to date. Furthermore, we demonstrate continuous-wave 520 nm green-emitting laser diodes with over 60 mW output power and 1.9% wall plug efficiency. The rapid performance evolution of laser diodes fabricated on non-c-plane orientations is validation of the benefits resulting from increased electron–hole overlap, reduced effective hole mass, and increased design flexibility.

Advances in high-brightness semiconductor lasers

We present recent advances in high power semiconductor laser bars and arrays at near infrared and eye-safe wavelengths. We report on increased spectral brightness with internal gratings to narrow and stabilize the spectrum and increased spatial brightness in multimode and single mode devices. These devices have the potential to dramatically improve diode pumped systems and enable new direct diode applications.

High-brightness semiconductor lasers

We present recent advances in high power semiconductor lasers including increased spectral brightness using on-chip internal gratings and increased spatial brightness at wavelengths from the near infrared to the eye-safe regime.

47.1: Invited Paper: Progress in Green and Blue Laser Diodes and Their Application in Pico Projection Systems

With the emergence of the direct emission green laser diodes based on InGaN technologies, pico projection systems utilizing an all-direct diode light engine will soon be available. Such systems will provide a wide range of benefits over existing light engine technologies. Here we will discuss these benefits and present Soraas progress on the development of high-efficiency direct diode green and blue lasers based on nonpolar/semipolar InGaN.

Advances in semiconductor laser bars and arrays

Advances in high power semiconductor lasers such as increased spectral brightness, increased spatial brightness, and reduced cost architectures at wavelengths from the near infrared to the eye-safe regime have the potential to dramatically improve diode pumped systems and enable new direct diode applications. 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 arrays at eye-safe wavelengths are presented.

Advances in semipolar InGaN laser diodes (Conference Presentation)

We present state-of-the-art performance from laser based light sources based on semipolar GaN. Recent advances toward the commercialization of blue, InGaN semipolar laser diodes are described. Additionally, we introduce next generation white light sources based on laser-pumped phosphor architectures.

Ultracompact visible R-G-B lasers for defense applications

Compact, efficient visible lasers are important for heads up displays, pointing and illumination, undersea communications, and less than lethal threat detection. We report on high power red, green, and blue lasers with output powers above 3 watts and efficiencies greater than 20%, 15%, and 5% respectively.

High Brightness Semiconductor Lasers with Internal Gratings

We present recent advances in high power semiconductor lasers including increased spectral brightness using on-chip internal gratings, increased spatial brightness, and reduced cost architectures at wavelengths from the near infrared to the eye-safe regime.

Conductively cooled high-power high-brightness bars and fiber-coupled arrays

Solid-state-laser and fiber laser pumping, reprographics, medical and materials processing applications require high power, high-brightness bars and fiber-coupled arrays. Conductively cooled laser diode bars allow customers to simplify system design and reduce operational size, weight, and costs. We present results on next generation high brightness, high reliability bars and fiber-coupled arrays at 790-830 nm, 940 nm and 980 nm wavelengths. By using novel epitaxial structures, we have demonstrated highly reliable 808 nm, 30% fill-factor conductively cooled bars operating at 60W CW mode, corresponding to a linear power density (LPD) of 20 mW/μm. At 25°C, the bars have shown greater than 50% wall-plug-efficiency (WPE) when operating at 60W. Our novel approach has also reduced the fast-axis divergence FWHM from 31° to less than 24°. These bars have a 50% brightness improvement compared to our standard products with this geometry. At 980nm, we have demonstrated greater than 100W CW from 20% fill-factor conductively cooled bars, corresponding to a LPD of 50 mW/µm. At 25°C, the WPE for 976nm bars consistently peaks above 65% and remains greater than 60% at 100W. We coupled the beam output from those high-brightness bars into fiber-array-packages (“FAPs”), and we also achieved high-brightness and high-efficiency FAPs. We demonstrated 60W from a 600µm core-diameter fiber-bundle with a high WPE of 55%, and a low numerical aperture of 0.115. The brightness of such FAPs is four times higher than our standard high-power 40W FAP products at Coherent. Ongoing life test data suggests an extrapolated lifetime greater than 10,000 hours at 80W CW operating-condition based on 30%FF conductively cooled bar geometry.