An illumination system consists of the light source(s), some optical components and a target, the latter literally carrying the specs which are defined by the field of application. In our review we will discuss design, technology, and fabrication of light sources and components. As there are considerable differences between the many fields of application, we start with a general view and derive the technical specialties afterwards.

In some cases we will name representative suppliers without the intention to exclude others. With the help of such a reference, the interested reader will be able to gather information, understand the product and find similar suppliers easily.

We restrict the review to visible, incoherent light and related optical elements.