Home > TRAP radiometers/joulemeters available from Warsash Scientific

TRAP radiometers/joulemeters available from Warsash Scientific

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article image TRAP series radiometers/joulemeters

Spectrum Detector has designed a series of large aperture, high quantum efficiency optical TRAP detectors based on an ideal concept developed at NIST Boulder (National Institute of Standards and Technology).

This technology plays a critical role in NIST spectral calibration transfer standards.

By combining several high quantum efficiency photodiodes and a large, concave, broadband mirror in a multi-bounce optical configuration we can TRAP 99% of the light in the spectral range of 400 to 950nm.

By using a pyroelectric detector in this configuration the spectral response from 0.25 to 15µm is flat to 1% or better. This is a dramatic improvement over a typical calibrated single element detector which has an accuracy of +/-3%.

Optical TRAP detectors are intended for use in optical calibration and correlation of FO power meters, laser power meters and optical detectors.

If a user gets varying results between optical power meters when measuring a single source, he can employ an SPT-DR-TRAP system as an absolute standard. This way, he can correlate his meters to the TRAP system and minimize the measurement uncertainty.

The TRAP series, available from Warsash Scientific , is available in radiometer and joulemeter configurations with a wide range of standard smart probes to select from, including Si, Ge and InGaAs photodiodes or Pyroelectric detectors.

The ability to mix and match a variety of detector probes, oscilloscopes and lock-in amplifiers with a power module provides great versatility for any application.

The TRAP system is ideal for any ultra-precise measurement application, providing an affordable calibration standard at an equivalent cost as a single point detector calibration at NIST.


  • Primary standard for optical power measurements 0.19 to 1.0µm
  • Entire system is contained within single, compact, USB-powered probe housing
  • Radiometer measurement performance 20µW to 200mW FS, with minimum resolution of 50nW
  • Joulemeter measurement performance 2µJ to 2mJ, with minimum resolution of 100nJ
  • LabView applications software that provides single and dual-channel measurement capability, powerful automation routines and sophisticated data collection, statistics and graphic presentation
  • Pyroelectric, silicon and germanium detectors
  • Versatile optical front end compatible with Thor Labs SM1 accessories
  • Broadband calibration standard

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