Patent ID: 7804042

Claim:
A method of laser-annealing a substrate, comprising: emitting laser radiation at a laser wavelength between about 805 nm and about 815 nm; passing said laser radiation in a forward direction through a beam splitter and projection optics to a substrate, at least one of the beam splitter and the projection optics comprising material having a fluorescence wavelength band lying at or above about 855 nm and above said laser wavelength; imaging the region of the substrate illuminated by the laser radiation onto a pyrometer through a pyrometer optical path, and admitting radiation through said pyrometer optical path lying in a pyrometer response band above the laser wavelength and below the fluorescence wavelength band; and blocking radiation wavelengths in the pyrometer optical path below a cut-off wavelength edge transition and passing radiation wavelengths above said wavelength edge transition, said wavelength edge transition being less than 10 nm wide, said wavelength edge transition being above said laser wavelength and below said pyrometer response band; blocking radiation wavelengths in the pyrometer optical path that lie within and above the fluorescence wavelength band.