Paper
11 October 2012 Gain in optical coatings
Angus Macleod, Christopher Clark
Author Affiliations +
Abstract
The introduction of gain into an optical medium is most easily accomplished by reversing the sign of the extinction coefficient. The theoretical expression for reflectance at a simple boundary between a dielectric, lossless incident medium and a medium with a finite extinction coefficient, however, takes no account of the sign of the extinction coefficient In such an arrangement, therefore, can the presence of gain possibly result in an enhanced reflectance? Opinions in the literature differ but tend to find enhancement beyond the critical angle and none below. This study examines both cases and shows that all results are in fact correct but they are not necessarily stable and it is their stability, or lack of it, that leads to the different results.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Angus Macleod and Christopher Clark "Gain in optical coatings", Proc. SPIE 8486, Current Developments in Lens Design and Optical Engineering XIII, 848612 (11 October 2012); https://doi.org/10.1117/12.930017
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KEYWORDS
Reflectivity

Reflection

Mass attenuation coefficient

Dielectrics

Thin films

Optical coatings

Phase shifts

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