A collector that includes a laser produced plasma (LPP) extreme ultra
violet (EUV) light source and a first optical path from the source to a
mirror. The mirror is the first mirror that light emitted from the source
and traveling along the first optical path impinges upon. The collector
also includes a second optical path from the source to another mirror.
The other mirror is the first mirror that light emitted from the source
and raveling along the second path impinges upon. The mirror and the
other mirror are oriented relative to the source such that light from the
source traveling along the first optical path travels in a direction
opposite to light traveling from the source along the second optical
path. A collector having a discharge extreme ultra violet (EUV) light
source.