Hello Colleagues,
During my recent spectroscopic ellipsometry measurements of a sapphire substrate, I encountered observed a small yet apparent depolarization. Despite my efforts, I have been unable to identify the cause behind this phenomenon.
I have considered various factors, mainly related to substrate preparation, or potential equipment-related issues, but no definitive explanation has emerged so far.
If any of you have encountered a similar depolarization effect in your work or have any knowledge that could help solve this issue, I would greatly appreciate your input.
Best regards,
Aynı veya farklı substrat düzeyinde oldukları için depolarizasyon meydana gelmiş olabilir.
The surface of the sapphire is perfectly flat, so this is not the reason.
Saphire is centrosimetric so it should not be anysotropic, unless the surface roughness or the TTV are large within the spot size. Are both interfaces Saphire/air?
How are you dealing with back surface reflections? Are you using any experimental technique (e.g. spatially filtering additional beams, roughening back surface, using an index match material) or numerical technique? Are you aligning the sample before each measurement? Have you tried reducing monochromator bandwidth or using a smaller detector aperture to reduce angular spread?
Thickness variation, surface roughness, backsurface reflections, non-zero bandwidth and angular spread can be included in the model. See if the fit improves including one or more non-idealities. Include them one by one, and just if the fit improves with each one.
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