Adrian Stefan Avramescu

True blue InGaN laser for pico size projectors

Red, green and blue semiconductor lasers are of great interest for full color laser projection. Mobile applications require low power consumption and very small laser devices. InGaN lasers are the best choice for the blue color in applications with output power requirements below 100mW: (1) they have much higher wall plug efficiencies than conventional blue frequency doubled diode pumped solid state lasers and (2) they are more compact than semiconductor IR lasers with subsequent second harmonic generation. We present blue InGaN lasers with high efficiency at a power consumption of several 100mW. Excellent epitaxial quality permits low internal losses. Threshold current densities and slope efficiencies are further optimized by improving the facet coating. The laser threshold current is as low as 25mA and the slope efficiency reaches 1W/A. We present a wall plug efficiency of 15% at output power levels of 60mW.

An industry perspective on the optimization of InGaN lasers and LEDs via modeling

In this paper, we illustrate the role of modeling in the development of commercial nitride-based lasers and LEDs. Aside from optimizing device performance, joint analysis of simulations and experimental results can shed light into the intrinsic properties of the InGaN/GaN material system.

Recent progress in blue/green InGaN laser diodes

Recently for on-the-go multimedia appliances an interesting accessory is the mobile pico-projector based on laser diodes sources. Good colour reproduction and no necessity to focus the image are the main advantages deriving from laser light use. Such products are demonstrated and also their commercial availability was announced. For blue light emission the direct output of InGaN based lasers is used, while for the green the light emission of GaAs based lasers must be converted by a nonlinear crystal. Due to the inherent difficulties and bigger size of such a light source there is an increased interest to use the direct output of an InGaN based laser diode with emission in the green range.