1."What is the minimum thickness that can be modeled in Zemax? Is it possible to model thickness in the nanometer (nm) range?

2.In Zemax Non-Sequential Mode, I am trying to analyze the efficiency of light reaching a sensor. The setup includes a flat plane with thicknesses of 400nm and 1.97μm, a sensor size of 18μm × 24.7μm, and a light source with a 120° emission angle. However, I am encountering a 'Geometric Error' during ray tracing. What could be causing this error, and how can I resolve it?