Layer Sensitivity
The Layer Sensitivity option allows you to estimate the design sensitivity to layer thickness variations. OptiLayer provides two possibilities: layer sensitivity with respect to design target and with respect to the theoretical design performance. You can specify relative varialtions in layer thicknesses \(\delta_H, \delta_L\). The disturbed designs have thicknesses \(d_1,d_2,..., d_i(1+\delta_{H,L}),...,d_m. \) For each disturbed design, the variations \(\Delta MF_i\) with respect to design target (Eq. (1)) or to theoretical spectral characteristic \(S\) (Eq.(2)): \[ \Delta MF_i=MF(d_1,...,d_i(1+\delta_{H,L},...,d_m)MF(d_1,...,d_m)\;\; Eq. (1)\] \[ \Delta MF_i=S(d_1,...,d_i(1+\delta_{H,L},...,d_m)S(d_1,...,d_m)\;\; Eq. (2)\] 

Then, layer sensitivities \(LS(i)\) are calculated and ranged from 0 to 100%. The corresponding ranges are displayed. The layer ranked number 1 in the Sensitivity order is the layer that is most sensitive to change, it is assigned a relative sensitivity of 100%. \[ LS(i)=\frac{\Delta MF_i}{\max_{i=1,...,m}\Delta MF_i}\cdot 100\%\] In the spreadsheet, absolute layer sensitivities are shown. In the Chart, relative layer sensitivities are plotted. 

Theoretical transmittance of a multilayer design. Crosses represent the design target. 
Layer sensitivity calculated with respect to design target. Layer sensitivity calculated with respect to the theoretical design performance. 