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The NIST photodetector calibration service characterizes the absolute spectral responsivity and spatial uniformity of photodetectors for use in industrial and government labs. The calibration service provides calibrated silicon photodiodes for sale and special tests of customer supplied detectors. The calibration service uses two monochromator-based Spectral Comparator Facilities (SCFs) to measure from 193 nm to 1800 nm. The visible to Near-Infrared (Vis/NIR) SCF typically measures the uniformity and absolute spectral responsivity of photodiodes in the 350 nm to 1800 nm spectral region. The Ultraviolet (UV) SCF typically measures the uniformity and absolute spectral responsivity of photodiodes in the 200 nm to 500 nm spectral region. The photodetector calibration service is documented in updatedNIST SP 250-41-2008 PDF.

Calibration of detectors in the extreme ultraviolet (5 nm to 254 nm) spectral region is available from another division at NIST. A new infrared (IR) spectral responsivity facility is being developed. Presently special tests of IR detectors can be performed in the 2 µm to 20 µm wavelength range under Service ID Number 39090S. Customers should contact George Eppeldauer to receive information or to discuss measurement details before submitting a formal request.

Click on the items below to read more about:

Vis/NIR SCF

The Vis/NIR SCF operates from 350 nm to 1100 nm using silicon photodiodes as working standards and from 700 nm to 1800 nm using germanium photodiodes as working standards. The Vis/NIR SCF uses the direct substitution method and automated translation stages to position the photodetectors for measurement. The test detectors as well as the working standards are fixed onto optical mounts that rotate and tilt for accurate alignment. A variety of sources can be selected. Typically a 100 W quartz-halogen lamp is used as the source in the Vis/NIR SCF. A shutter is located just after the monochromator exit slit. A monitor detector located after the monochromator measures source fluctuations.

Figure 1. Schematic of the Vis/NIR SCF.   [D]

Figure 1. Schematic of the Vis/NIR SCF.


UV SCF

The UV SCF operates from 193 nm to 500 nm using UV enhanced silicon photodiodes as the working standards. The UV SCF is very similar in configuration and operation to the Vis/NIR SCF with the major differences described here. A rotary stage is used in the UV SCF and currently only one test detector at a time can be measured. The test and working standard detectors are fixed onto optical mounts that rotate and tilt. Only the test detector can automatically be positioned in the horizontal and vertical planes. The working standards are positioned manually. Typically an argon arc is used as the source in the UV SCF.

Figure 2. Schematic of the UV SCF.   [D]

Figure 2. Schematic of the UV SCF.


Absolute Spectral Responsivity Scale Realization

The Primary Optical Watt Radiometer (POWR) is the primary standard for the optical power scale, and trap detectors are used as transfer standards.

For technical information or questions, contact:
Jeanne Houston
Phone: 301-975-2327
FAX: 301-975-6991
Email: jeanne.houston@nist.gov 		  Thomas Larason
Phone: 301-975-2334
FAX: 301-869-5700
Email: thomas.larason@nist.gov 		  Yoshi Ohno
Phone: (301) 975-2321
FAX: (301) 840-8551
Email: ohno@nist.gov

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Online: September 1997   -   Last updated: May 2007