Our desktop system for absolute R and T measurements has been modified: You can now use a combination of the WOSP-LEDO-P light source and an Avantes spectrometer to record spectra in the range 270 … 1050 nm. A polarizer is an optional add-on.
The system needs a table of dimensions 1000 mm * 700 mm or larger (table not included in the system). The new design allows reflectance measurements at 8° angle of incidence which was not possible with the previous version.
Following customer demands we have added a small halogen light source to the LEDO system. This enhances the intensity at the NIR end of the spectrum. Although in this case the light source is not based on LEDs alone we still call it LEDO (actually: LEDO-P): The built-in halogen bulb has an average lifetime of 20,000 hours which is in the range of the expected LED lifetime.
There is a strong increase in counts in the NIR range due to the halogen lamp (blue vs. green in the graph below):
Consequently, the NIR noise is reduced and we can extend the useful spectral range up to 1050 nm (100% line, measurements have been done with an Avantes EVO spectrometer):
Spectra taken with the new light source (200 ms integration time, 25 averages, 5 seconds total measuring time):
Stability in time: The graph below shows 25 sample spectra taken during a period of 3 minutes: