For mixing different light colors from different LEDs or energized phosphors, an elongated mixing tunnel is used having a reflective inner surface. LEDs of different colors are optically coupled along the length of the mixing tunnel and at a first end of the tunnel. Light coupled along the length of the tunnel is reflected by an angled dichroic mirror that selectively reflects the incoming color light towards a single output port of the mixing tunnel. The dichroic mirror passes all other colors of light being transmitted towards the output port of the tunnel. Two, three, or more colors of LEDs can be used. Efficient and compact ways to energize phosphors are also described. Other optical techniques are also described.