The FL250A-LP1-DIF-33 uses the LP1 absorber, whose spectral response is not flat, and also has an alumina diffuser – whose spectral response is also not flat. Although we do have the full measured curve as part of the regular calibration process for LP1 sensors, doing so for a sensor with a diffuser is for various reasons technically problematic.
As stated in the spec, then, we calibrate this sensor at the 3 wavelengths 532nm, 75nm and 1064nm. The sensor responds, however, at all wavelengths in the specified spectral range.
If you need to measure at a wavelength other than one of the 3 calibration points, the practical solution would be as follows:
- Set the meter's wavelength to one of the calibrated wavelengths, say 1064nm (or whichever is closest to your wavelength)
- Take the reading of the laser
Calculate a correction factor for your wavelength using the following graph: