Uncertainty Propagation for NIST Visible Spectral Standards

Area of Science:

• Metrology
• Optical Engineering
• Radiometry

Background:

• Accurate spectral standards are crucial for reliable detector and source characterization.
• Existing methods for uncertainty propagation in spectral measurements require refinement, especially considering wavelength correlations.

Purpose of the Study:

• To propagate uncertainties in NIST spectral standards for detectors and sources in the visible range.
• To detail uncertainty propagation through fitting and transfer spectral measurements.
• To provide recommendations for interpolating spectral irradiance values.

Main Methods:

• High accuracy cryogenic radiometer measurements were used as the basis for uncertainty propagation.
• Partial correlations between spectral values at different wavelengths were estimated.
• Uncertainty propagation was analyzed through fitting, transfer spectral measurements, and the spectral comparator facility.

Main Results:

• A comprehensive method for propagating uncertainties in spectral standards, considering correlations, was developed.
• Detector uncertainties were successfully propagated for external calibrations and internal photometric quantities.
• Uncertainties in spectral irradiance were derived and propagated to calibrated artifacts.

Conclusions:

• The developed method provides a robust framework for assessing uncertainties in spectral standards.
• Accurate estimation of correlations is vital for precise radiometric calculations.
• Interpolation is recommended over fitting for NIST-provided spectral irradiance values to minimize uncertainty.