Radiometry is the detection and measurement of the electromagnetic spectrum (ultraviolet, visible, and infrared).

Please SCROLL DOWN to review our selection of RADIOMETERS for use in all types of radiometric measurements.

Radiometry is light measurement

Radiometry is the detection and measurement of light waves in the optical portion of the electromagnetic spectrum which is further divided into ultraviolet, visible, and infrared light.

All light measurement is considered radiometry with photometry being a special subset of radiometry weighted for a typical human eye response.

Manipulating light for more accurate measurement

Light waves behave like all electromagnetic waves in that they interfere with each other, become directionally polarized, or bend when passing an edge. Because of these properties, light waves can be predictably manipulated for increased or decreased amplitude or even filtered by wavelength or a band of wavelengths by means of various filters, mirrors, lenses, prisms, gratings, and other input optics.


These principals make it feasible to tailor a light detector to match a particular application.

In most cases, when making radiometric measurements with silicon photodiodes, a flat spectral response filter is used to even out the detector's innate sensitivity to the red portion of the spectrum versus the blue. This flat response allows the detector to accurately measure light at one wavelength versus another. This is particularly useful if the spectral output of the light source is unknown or likely to vary with operating conditions or application requirements.

In the event that a particular section of the output from a light source needs to be isolated, a detector with a narrower response can be used, or a band pass filter can be placed on a broad response detector to tailor it’s response to measure just the required portion of light. Narrow band filters can also be used to isolate a very narrow portion of light such as that of a specific mercury emission line.

Radiometry instrumentation for nearly any application

International Light Technologies (ILT) offers a broad array of radiometry detectors to allow configuration of a radiometer system to measure nearly any application from the UV (160 nm) to far-Infrared (40 um). We also have high-gain radiometry detectors for very low level light detection and our powerful ILT950 Wideband Spectroradiometer or economical ILT550 Spectroradiometer for complete, turnkey spectral measurements.


Need Light Measurement Applications Help? Click on THIS LINK to Contact an ILT Light Measurement Expert


Application Common Sources Spectral Range ILT System Options
Click Links Below
Measurement Range Units
  Examples: All Sources of Light; Lamps; Flames; Chemical Reactions 200-1100 nm ILT950 Spectroradiometer Customized spectrum W/m²/nm
    250-900 nm ILT550 Spectroradiometer Customized spectrum W/m²/nm
    400-1064 nm ILT5000 Radiometer,
SED033/F/W Detector
7.69e-11 to 1.54e-1 W/cm²
    400-1064 nm ILT1700 Radiometer,
SED033/F/W Detector
1.54e-10 to 1.54e-1 W/cm²
    400-1064 nm ILT2400 Radiometer,
SED033/F/W Detector
4e-9 to 7e-2 W/cm²
    400-1064 nm ILT1000/F/W Flat
Response Irradiance
8e-8 to 7e-2 W/cm²
    400-700 nm ILT5000 Radiometer,
SED033/F/HMR/W Detector
2-10 to 1e-1 W/cm²
    400-700 nm ILT1700 Radiometer,
SED033/F/HMR/W Detector
2.41e-10 to 2.41e-1 W/cm²
    400-700 nm ILT2400 Radiometer,
SED033/F/HMR/W Detector
7e-9 to 1e-1 W/cm²
    250-400 nm ILT5000 Radiometer,
SED005/WBS320/W Detector
2.33e-8 to 2.33e+0 W/cm²
    250-400 nm ILT1700 Radiometer,
SED005/WBS320/W Detector
2.33e-9 to 2.33e+0 W/cm²
    250-400 nm ILT2400 Radiometer,
SEL005/WBS320/TD Detector
1e-7 to 1 W/cm²
    250-400 nm ILT1005/WBS320/W
UV Irradiance Monitor
2e-6 to 1e+0 W/cm²
    850-1700 nm ILT5000 Radiometer,
SED007/W Detector
4e-11 to 3e-2 W/cm²
    850-1700 nm ILT1700 Radiometer,
SED007/W Detector
7.14e-11 to 7.14e-2 W/cm²
    850-1700 nm ILT2400 Radiometer,
SED007/W Detector
2e-9 to 3e-2 W/cm²
    850-1700 nm ILT1007/W NIR
Irradiance Monitor
4e-8 to 3e-2 W/cm²
    200-4200 nm ILT5000 Radiometer,
SED623/K9 Detector
2e-5 to 1e-1 W/cm²
    200-4200 nm ILT1700 Radiometer,
SED623/K9 Detector
2.00e-5 to 2.22e-1 W/cm²
    200-4200 nm ILT2400 Radiometer,
SEL623/K9 Detector
2e-5 to 1e-2 W/cm²
    200-40,000 nm ILT5000 Radiometer,
SED624/K9 Detector
2e-5 to 1e-1 W/cm²
    200-40,000 nm ILT1700 Radiometer,
SED624/K9 Detector
2.00e-5 to 2.22e-1 W/cm²
    200-40,000 nm ILT2400 Radiometer,
SEL624/K9 Detector
2e-5 to 1e-1 W/cm²
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HIGH GAIN, VERY LOW LIGHT LEVELS Photon counting, Chemical reactions, Phosphorescence 250-600 nm ILT1700 Radiometer,
SPM068/QNDS3/W Detector
1.05e-12 to 1.05e-5 (HIGH) W/cm²
    250-600 nm ILT1700 Radiometer,
SPM068/QNDS3/R Detector
1.37e-11 to 1.37e-4 (HIGH) W/cm²/sr
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* All Radiometers, Photometers, Spectroradiometers are NIST Traceable.
* If units of measure are not shown please contact us (empirical units also available i.e. fc, fL, nits, lm/ft²).