Radiant Imaging
CCD light measurement systems, light source characterization files, optical and illumination design software, and optical and illumination engineering services.
http://www.radimg.com/

3D Scene
Illustrates most of the modeling, illumination, and rendering 3D objects. Covers Z-buffer, Shading, Phong illumination, and Ray Tracing.
http://www3.telus.net/Voiculescu/scene_3d/index.html

Global Illumination Compendium by Philip Dutré
This page contains the Global Illumination Compendium, an effort to bring together most of the useful formulas and equations for global illumination algorithms in computer graphics.
http://www.cs.kuleuven.be/~phil/GI/

ERCO
Offers products for architectural illumination from spotlights and recessed luminaires to intelligent lighting control systems.
http://www.erco.com/

StockerYale Inc.
Developer and manufacturer of high-quality specialty optical fiber, optical networking components and specialized illumination systems.
http://www.stockeryale.com/

StockerYale, Inc.
Developer and manufacturer of high-quality specialty optical fiber, optical networking components, and specialized illumination systems.
http://www.stockeryale.com/

Cymer, Inc.
Cymer is the world's leading supplier of excimer laser illumination sources, the essential light source for deep ultraviolet (DUV) photolithography systems used in the manufacturing of semiconductors.
http://www.cymer.com/

DeVore Aviation Corporation of America
DeVore Aviation Corporation of America- A manufacturer specializing in FAA approved lighting systems for aircraft and helicopters.
http://www.devoreaviation.com/

Articulight
Articulight: Led Color Changers, Searchlights, Spectacolour 18 PC
http://www.articulight.com/

OSRAM Opto Semiconductors
Masnufacturers LEDs for illumination, sensing and visualization.
http://www.osram-os.com