MKS CONFIDENTIAL
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IPL Source - Spectral Distribution
Since we calibrate the IPL sensor using a pulsed 755nm laser and the measurement involves a spectral
distribution of light typically from 600 to 1000nm, we also need to know the spectral distribution of the IPL
source. This was determined using a calibrated spectrum analyzer. Since there is only a weak dependence of
calibration on the spectral profile, even if the profile of a particular IPL source differs from the one below, the
calibration is not affected much.
Angular and Spectral absorption of the LP2 absorber
The measured values of the angular and spectral absorption of the LP2 coating are shown below. Note the small
dependence on angle and wavelength.
Transmission of the glass as a function of Angle and Wavelength
Below left, we see the transmission of the glass as a function of angle. Note that at the critical angle of 42
degrees, the transmission falls to zero. Note also that the spectral dependence below right is small except at the
shortest wavelengths.
