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spectroradiometer irradiance
spectroradiometer irradiance

Radiometry deals with the measurement of all optical radiation inclusive of the visible portion of this radiant energy. Irradiance is a parameter of radiometry. It describes the amount of radiant power impinging upon a surface per unit area. Irradiance measurements can be done in the UV, VIS and NIR wavelength ranges.

We work with a variety of irradiance applications ranging from pulsed solar simulator characterisation to free space measurements of radiant sources such as street lights. The AvaSpec line of instruments provides exceptional resolution and straylight rejection to ensure the accuracy of these measurements.


Typical system configurations involve one or more spectrometers configured for the appropriate range of 200-400nm for UV irradiance, 360-1100nm for VIS irradiance and 1100-2500nm for NIR irradiance. While broadband configurations covering 200-1100nm are feasible with one spectrometer, optimal performance is achieved with dedicated UV (200-400nm) and VIS/NIR (400-1100 nm) channels. The spectrometer or group of spectrometers is connected via fibre optic cable to a diffuser with a known surface area and the entire system is calibrated against a NIST traceable source for irradiance. We also offer a variety of cosine diffusers and integrating spheres for irradiance applications. The calibrated system is shipped as an integrated system (connected altogether) and should remain in this configuration in order to ensure the integrity of the calibration. FC/PC connectors are recommended in place of the standard SMA, which enable repeatable disconnection and reconnection of the fibre optics, so the system may be disconnected for transportation etc.

Customers that wish to conduct their own calibrations may consider one of our intensity calibration sources. The AvaLight-HAL-CAL-Mini is available for VIS/NIR wavelengths (360-2500nm), and the AvaLight-DH-CAL is available for UV/VIS wavelengths (200-1100nm).

The Avantes AvaSoft-IRRAD software module enables irradiance parameter measurements such as radiometric quantities - µWatt/cm2, µJoule/cm2, µWatt or µJoule, photometric quantities Lux or Lumen, colour coordinates X, Y, Z, x, y, z, u, v, colour rendering index and colour temperature, and number of photons µMol/s•m2, µMol/m2, µMol/s and µMol. AvaSoft-IRRAD software also facilitates the performance of irradiance intensity calibrations.

Ava-IRRAD Typical Irradiance System
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