Indices Correction Model

Indices Correction option is purposed for the post-production characterization of layer refractive indices. For various reasons layer refractive indices in a multilayer stack may vary from the corresponding indices being determined from single layer measurements and then used for the computations of optical coating designs. The Indices Correction option allows for the determination of practical indices more accurately and thus provides a feedback to the design procedure. The following refractive index and extinction coefficients models are available:

data fitting

 

 

Fitting of experimental transmittance data by model data before and after application of indices corrections model (put the mouse on and out of picture)
refractive indices correction Refractive index offsets calculated in the course of the reverse engineering process.

The Index drift models allow you to include into consideration possible drifts of the refractive indices of layer materials:

  • Constant drifts (offsets) - the same for all layers of the chosen material
  • Linear drift assuming linear dependency of the index drift on the layer number
  • Exponential drift assuming the following dependency on the layer number j:

\[ \delta n_j=C\exp(-\alpha j)\]

Exponential type of drifts usually provides large deviations at the beginning of deposition that are rapidly decreasing with the layer number.

Read more in our papers:

  1. T. Amotchkina, M. Trubetskov, V. Pervak, B. Romanov, and A. Tikhonravov, "On the reliability of reverse engineering results," Appl. Opt. 51, 5543-5551 (2012).
  2. A. Tikhonravov, T. Amotchkina, M. Trubetskov, R. Francis, V. Janicki, J. Sancho-Parramon, H. Zorc, and V. Pervak. "Optical characterization and reverse engineering based on multiangle spectroscopy." Appl. Opt. 51, 245-254 (2012).

  3. T. Amotchkina, S. Schlichting, H. Ehlers, M. Trubetskov, A. Tikhonravov, and D. Ristau, "Computational manufacturing as a key element in the design-production chain for modern multilayer coatings," Appl. Opt. 51, 7604-7615 (2012).

  4. T.V. Amotchkina, M.K. Trubetskov, V. Pervak, S.Schlichting, H. Ehlers, D. Ristau, and A.V. Tikhonravov. "Comparison of algorithms used for optical characterization of multilayer optical coatings." Appl. Opt. 50, 3389-3395 (2011).
  5. T. V. Amotchkina, M. K. Trubetskov, A. V. Tikhonravov, S. Schlichting, H. Ehlers, D. Ristau, D. Death, R. J. Francis, V. Pervak, Quality control of oblique incidence optical coatings based on normal incidence measurement data, Optics Express, Vol. 21, Issue 18, pp. 21508-21522 (2013).