Laser-Driven Visible Solid-State Light Source for Etendue-Limited Applications

We present experimental results on a low-cost light source that utilizes commercially available 405-nm/445-nm lasers to drive phosphor-based optical cavities generating speckle-free red, green, and blue (RGB) light at selected etendue and power values. By combining more 405/445-nm laser beams to drive the optical cavities, enough RGB light can be generated for the most demanding etendue-limited applications such as automotive headlights, biomedical devices and projection systems. We report efficacies of 17, 18, and 14 lm/W for the red (610 nm), green (530 nm), and white light, respectively, at an etendue of 27 mm ² .sr.