Ocean Optics SpectraSuite - Manual (Page 100)

7: Processing Menu Functions
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Relative Irradiance
Select Processing | Processing Mode | Relative Irradiance to switch the current window into Relative
Irradiance mode. You can also click
in the graph’s toolbar.
Before you can access Relative Irradiance mode, you must take a reference spectrum in Scope mode of a
blackbody of known color temperature. Additionally, you must obtain a dark spectrum by removing the
fiber from the reference lamp and preventing light from entering it.
Relative irradiance spectra are a measure of the intensity of a light source relative to a reference emission
source. SpectraSuite calculates relative irradiance using the following equation:
Where:
B

= Relative energy of the reference calculated from the color temperature
S

= Sample intensity at wavelength 
D

= Dark intensity at wavelength 
R

= Reference intensity at wavelength 
See Experiment Tutorials for information on conducting an experiment in Relative Irradiance mode.
Absolute Irradiance
Irradiance is the amount of light present on a particular area, such as the fiber’s cross-section at its tip, a
cosine corrector’s surface, or the integrating sphere’s surface (measures the total optical output of a light
source inserted into the integrating sphere).
Conversions
When using Absolute Irradiance, this menu selection allows you to choose from the following values for
the Y-axis: J/m
2 /nm, J/nm, W/m 2 /nm, W/nm, dBm/nm, eV/nm, mol photons/nm, µJ/cm 2 /nm, µJ/nm,
µW/nm, µmol photons/nm.
Scope
This menu selection allows you to completely control signal processing prior to calibrating the spectral
response of your system and taking measurements. Use caution when operating in Scope mode since this
mode represents a combination of several factors such as the intensity of the light source, the reflectivity
of the grating and mirrors in the spectrometer, the transmission quality of the fibers, the response of the
detector, and the spectral characteristics of the sample.