Using FTIR spectral response signals to separate, characterize and quantify the effects of silicone or rubber-based adhesive materials on microsphere lens enhanced MWIR SLS photo detectors

In our prior work we have analyzed, proposed global performance metrics, and shown how MWIR microsphere lens-enhanced single detectors have exhibited an increase in detector sensitivity and reduction in Noise to Signal Ratio (NSR). We have shown that, in general, the microsphere lens reduces the detector NSR independently of the increase in the enhanced detector sensitivity. We have also shown how microsphere lens material absorptions and misalignments can affect and reduce the microsphere lens-enhanced MWIR detector sensitivity. When placing a microsphere lens on a photo-detector, usually an optical silicone-or rubber adhesive is used to adhere and hold the microsphere lens on the single photo-detector. In this paper, we present a novel hybrid model-based and experimental data driven-based technique for analysis and characterization of the effect of the adhesive material on microsphere-lens-enhanced SLS single photo-detector sensitivity. In this work these adhesive material characteristics are modeled and compared to experimental microsphere-enhanced single detector FTIR spectral data. As we demonstrate here, based on the data considered, the results show that the adhesive material appears to adversely affect and decrease the detector overall sensitivity, and in some instances, by more than 40% depending on the adhesive material index of refraction, even with a high adhesive material transmittance/transparency.