Characterization of high-precision optical coatings for space applications on a micrometer scale

This thesis aims to design a microspectrophotometer capable of characterizing thin layers of coating measuring few hundred micrometers in size with high spatial and spectral resolution. The requirement of this microspectrophotometer arises because conventional spectrophotometers are limited in their spatial resolution. A setup is simulated using TracePro, resulting in an optical spot of 25 µm with a numerical aperture of 0.139, and the subsequent tolerance analysis is conducted in ZEMAX.
LabVIEW is used to automate the entire measurement process and the focus is determined using alignment crosses coated directly on a glass substrate, which shows a slightly elliptical focus of 65 and 60 µm in the X and Z axes respectively with an uncertainty of ± 5µm.
Finally, diferent coatings are analyzed and the results of the microspectrophotometer are val idated using a conventional spectrophotometer, Cary 5000. The validation shows that the results of the microspectrophotometer are similar to those of the Cary 5000. Thus, the microspectropho tometer can be used for optical analysis, as it ofers additional features such as a minimum step size of 0.8 µm and precise positioning of small coated structures (few hundred micrometers in size) with a high resolution of 1.6 µm derived from bidirectional repeatability.