The present invention relates to a physiological sensor comprising an emitter array having multiple light emitting sources, the multiple light emitting sources being configured to generate light having multiple wavelengths, a detector that generates an output signal responsive to the emitted light after absorption by tissue an attachment assembly that removably positions the emitter and the detector with respect to the tissue to form an optical path from said emitter through said tissue to said detector, and an encapsulate disposed in said optical path between a first subset of the plurality of light emitting sources and tissue that provides notch or band-pass filter characteristics according to emitted wavelengths so as to substantially attenuate secondary emissions from one or more of the multiple light emitting sources.
