Method for Controlling Radiation from a Source

A method for applying electromagnetic radiation to reactive materials in a reaction chamber comprising:

• introducing the electromagnetic radiation into the chamber;
• and increasing the probability of interaction of the electromagnetic radiation with the reactant materials by using multiple reflections to increase the optical path length of the electromagnetic radiation within the reaction chamber for which the amplitude of the electromagnetic radiation is above a threshold value;
• wherein the reaction chamber includes a plurality of pairs of opposed reflective surfaces of the chamber;
• wherein at least 50% and more preferably at least 80% or 90% of the reflections from the reflective surfaces are specular reflections;
• wherein at least one of the reflective surfaces of each pair is a concave mirror;
• the reflective surfaces of each pair being arranged to cause reflections of the electromagnetic radiation back and forth between the reflective surfaces within a volume defined by the reflective surfaces;
• the reflective surfaces of each pair being spaced one from the other so as to define a first side of the volume on one side of the reflective surfaces and so as to define a second side of the volume on an opposed side of the reflective surfaces;
• wherein the pairs are arranged side by side so that radiation escaping through a side of one volume enters a side of a next adjacent volume.