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Accurate characterization of photonic equipment is important for optical communications, medical devices, semiconductor lithography, manufacturing and materials processing. Accurate characterization of the solar irradiance and Earth radiance is of fundamental importance for weather and climate monitoring. The Photonic Radiometry Project develops the next generation of high-accuracy optical power measurement standards for laser power, detector spectral responsivity, detector linearity, the attenuation of transmission components, and space-based measurements of the Earth Radiation Budget. To calibrate detectors and instruments used to measure the power or energy produced by a laser, the sun, or reflected by the Earth, the project has developed a family of chip-scale bolometric standards that provide accurate , SI-traceable measurements of optical power with robust, micro-fabricated detectors.We are developing advanced microfabrication techniques coupled with carbon nanotube technologies to extend the performance of optical radiometric standards from room temperature to cryogenic temperatures, from the ultraviolet to the mm-wave, and from the laboratory to outer space.


Planar absolute cryogenic radiometer with multiwall vertically-aligned carbon nanotubes. Superconducting transition-edge sensor. Fully-lithographic fabrication.

Meeting the needs of the photonics industry and anticipating emerging technologies requires investigation and development of improved measurement methods and instrumentation. With few exceptions, all of the primary measurement standards for establishing traceability to fundamental units for radiometry are based on thermal detectors. This project develops state-of-art, absolute microfabricated thermal detectors with absorber coatings consisting of carbon nanotube arrays.

Major Accomplishments

  • International comparisons with Germany, Great Britain, Japan, Mexico, Switzerland, South Korea and Russia.
  • NIST bolometers in orbit in the Compact Solar Irradiance Monitor (CSIM)
  • Established first cryogenic primary standard to measure optical fiber-based laser power by exploiting innovative microfabrication techniques and vertically aligned carbon nanotube coatings, which are the most light-absorbing, or blackest, material ever made.
Created November 21, 2008, Updated July 21, 2020