| 摘要 |
A method and apparatus are provided to eliminate spectral interference variation contained in optical signals transmitted to an optical detector or array of optical detectors, the spectral variation deriving from the presence of a layer deposited on the detector having a different index of refraction from the detector. The practice of the invention involves optically coupling a plate to the layer using an adhesive, with the proviso that the plate, layer and adhesive have substantially the same index of refraction so that a composite thickness with the refractive index of the layer is formed. Given the inverse relationship between thickness of the layer and period of the interference in wavenumber, the effective increase in thickness of the layer yields a corresponding decrease in the period. Hence, the thickness of the plate may be selected such that the composite thickness of the layer, the plate, and the adhesive is sufficient to decrease the period so that it is masked by the normal shift of the interference structure over the range of incident angle of the optical input onto the detector or array of detectors, thereby effectively eliminating the spectral interference variation.
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