What is a Spectroradiometer?

15.09.2022What is a Spectroradiometer?

A Spectroradiometer is used to measure the wavelength and amplitude of light emitted from a source. 

How do AEON use a Spectroradiometer?

AEON recently used this system, along with a custom measurement positioning system (MPS), to characterise three optical windows having a diameter of 300mm!

Having searched for commercially available hardware which would suit the project requirements it became clear that performing optical testing on samples this large wasn't commonplace.

AEON developed a positioning system that would allow for precise linear and rotary control that we could automate to reduce overall measurement time, the result is a spectroradiometer system able to characterise optics up to 300mm in diameter over a staggering range of 250-2700nm in a single suite of hardware.

How does a Spectroradiometer work?

The way the spectroradiometer works is two-fold, it requires the determination of which wavelengths are to be measured (with a defined spectral resolution), and the physical positioning of the MPS to orient the sample to a defined, repeatable, measurement location.

Once this is known, the system then outputs a wavelength by receiving the light from the source, moving the triple grating turret inside of the monochromator to the desired wavelength position, which then outputs a beam that is presented to the detector via a collimator to ensure minimal divergence.

The detector then measures the resultant current response, this is repeated for the wavelength range required and provides a breakdown of the transmission of light through the sample material for each wavelength.

Spectroradiometer results

Periodic (unobstructed) "free air" measurements are taken with the sample material moved out of the path of the detector to enable the calculation of transmission (the difference between the current response in free air and through the sample material).

By performing this testing we are able to characterise the transmission of optical samples, this allows for the identification of any defects to be known in advance by providing a transmission map across the face of the sample.

In addition to transmission, the hardware is also configurable to allow for the measurement of reflectance and absorbance (with customisable reports available to suit the analyses required).

A further configuration of the hardware is for colorimetry, with the potential for source light characterisation (to the CIE 1931 diagram), by connecting a source light directly to the monochromator in place of the calibrated light sources used for the aforementioned test setups.

Spectroradiometer Device

Do you have optical equipment that needs testing?

If you require testing, analysis or characterisation of optical equipment, are looking for a suitable provider to facilitate the performance analysis of your optical equipment during a lifecycle, or are looking to find out more information about AEON's capabilities, please get in touch and book a consultation today!