Mo/Si multilayer reflectivity calculator

Explore a periodic mirror

Change the number of bilayers, period d and absorber fraction Γ. The plotted reflectivity and peak metrics update together. The period is the combined Mo-plus-Si thickness; Γ is the fraction occupied by Mo. For the default 6.9 nm period and Γ = 0.4, each period contains 2.76 nm Mo and 4.14 nm Si.

What the default model contains

All comparisons use 40 Mo/Si bilayers on silicon, a 6.9 nm period, and a molybdenum thickness fraction Γ of 0.4. The incident side starts with Si. Mo and Si densities are 10.22 and 2.33 g/cm³. The sweep covers 12.4–14.6 nm in 0.01 nm steps with unpolarized illumination. Angles are measured from the surface normal.

The default calculation uses smooth interfaces and normal incidence. Real mirrors can contain interlayers, contamination, thickness drift and roughness. Agreement with this idealized model is not evidence that a fabrication process will achieve the same result.

How should I read the peak metrics?

Peak reflectivity is the largest sampled value within the wavelength range. Peak wavelength and full width at half maximum describe that sampled band. If the peak moves outside the range, widen the workspace sweep before drawing a conclusion.

Next design questions

Explore incidence-angle dependence and interface roughness, then evaluate thickness variation in the Pro workspace.