Spectral Response

Spectral Response refers to the level of response as a function of wavelength of a radiometer.  Most radiometers offered by Biospherical Instruments either have a PAR response or a 10 nm wide narrow-band response which, when combined with an array of similar photodetectors across the spectrum, forms a spectroradiometer.

By default, AMOUR radiometers measure with the spectral response of a silicon photodiode (wide-band response between 250 and 1100 nm).  If the wavelength distribution of the source being measured is known, and the instrument is ordered with a response function calibration, the optical flux can be measured.

Spectral response functions offered for Biospherical Instruments' AMOUR radiometer. The functions were measured with the BSI spectral tester

The AMOUR radiometer features a selection of different filter assemblies that modify the spectral response of a silicon photodiode. The instruments can also be ordered with a large selection of filters, including narrow-band, and filters that mimic some physiological response function. These include: 

• Narrow-Band filters (~10 nm bandwidth) are normally used when the source distribution is known and typically confined to a small region, such as a laser, or where it is combined in an ensemble of radiometers spaced through the spectral region of interest, such that the entire spectrum can be reconstructed.
• PAR (Photosynthetically Active Radiation), which is confined to the 400–700 nm spectral region and is weighted with a quantum response, as opposed to most weighted spectral responses. Calibration units include moles/(cm² s), einsteins/(cm² s), and quanta or photons/(cm² s), and their MKS variants.
• Blue Light Hazard, which is defined as the potential for a photochemical-induced retinal injury resulting from radiation exposure at wavelengths primarily between 400 nm and 500 nm.
• Photometric Response, which describes the perceived brightness to the human eye.
• Erythema, which describes the wavelength-dependent sensitivity of the human skin to sunburn.

Additional response functions, tailored to customer needs, are available.