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Optical Radiation Group

Welcome

Optical Radiation thumbnail; Photo courtesy of the MOBY projectThe Optical Radiation Group maintains, improves, and disseminates the national scales for the candela (SI unit), spectral responsivity, reflectance, transmission, color, and appearance. Our staff participates in national and international committees and intercomparisons to ensure the acceptance of US radiometric, photometric, colormetric, and spectrophotometric standards and measurements. We also develop protocols for the calibration and validation of optical remote sensing instruments, perform long-term research, and maintain the infrastructure necessary to ensure the advancement of radiometry, photometry, colorimetry, and spectrophotometry measurement technology.

Programs/Projects

Detector metrology—High performance optical radiometers with selected optical detectors are being designed, characterized, and calibrated in the Optical Radiation Group for the 200 nm to 24 µm wavelength range. These …

Spectral responsivity measurement—NIST provides calibration of the spectral responsivity and spatial uniformity of photodetectors for use in industrial and government labs. These calibrations are carried out using two …

Optical medical imaging—The Optical Medical Imaging project was established to advance the application of optical imaging in surgical, clinical, and medical practices. Our goal is to promote measurement quality assurance …

Reflectance Measurements of Human Skin—The purpose of this human subjects study is to collect high-quality measurements of the reflectance spectrum of human skin and assess the variability across the population of subjects. The …

Aperture area measurements—Radiometric and photometric measurements require defining apertures. The accuracy to which these measurements can be accomplished requires minimization of the uncertainty in the aperture area.

Spectrophotometry—Spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. While relatively simple in concept, determining the …

Vision science—The Vision Science program was established to develop new photometric and colorimetric standards based on vision science to facilitate development of emerging technologies, such as solid-state …

Color and appearance—We are developing instrumentation, standards artifacts, and measurement protocols to characterize appearance attributes including color, texture, and gloss under a variety of geometrical conditions …

Applied spectroradiometry and imaging metrology—Spectroradiometers are widely used for acquiring colorimetric, photometric, and radiometric quantities with a single measurement for a variety of applications in LEDs and solid-state lighting (SSL) …

Molecular spectroscopy—The molecular spectroscopy sub-group carries out vibrational and rotational spectroscopic analyses on experimental data obtained primarily in the infrared (IR), Raman, and microwave (MW) region, as …

Building the next generation reference reflectometer—ROSI (Robotic Optical Scatter Instrument) is a new facility for measuring reflectance and scattering of materials in the ultraviolet to short-wave infrared wavelength range (250 nm to 2400 nm). …

Photometry—The purpose of photometry is to measure light in a way that takes the sensitivity of human visual system into account. While radiometry measures light in all spectral regions, including ultraviolet …

Solid-state lighting metrology—With the rise of new, energy-efficient solid-state lighting (SSL) systems has come the need for new performance metrics and measurement methods to address their unique construction and operating …

Theory of the optical properties of materials—The overarching objective of this project is reliably calculating the bulk optical properties of materials, such as complex index of refraction, absorption, and reflectance, across the …

Diffraction effects in radiometry—We want to quantify the breakdown of geometrical optics when computing the throughput of optical systems for the purpose of calculating "diffraction corrections" to radiometric measurements. We …