## Workbook Page OptProp Dash

The OPTICAL PROPERTIES DASHBOARD contains two very useful tools, OptProp and Sumrule.

**OptProp**

OptProp changes pairs of optical properties of materials (i.e. Real/Imaginary dielectric constants) into other pairs of optical properties.

- Reflectivity, phase
- Index of refraction n, extinction coefficient k
- Real, imaginary dielectric constants
- Real, imaginary interband transition strengths
- Bulk, surface EELS

**Sumrule**

Creates a spectrum of the effective number of electrons per molecule contributing to the optical transitions in the energy range up to Eo, starting from either the Imaginary dielectric constant or the Real interbace transition strength.

f sum rules for

- Imaginary dielectric constant
- Interband transition strength

f, index sum rules for

- Real, imaginary dielectric constants
- Real, imaginary interband transition strengths

**Bandgap**

An historical program. I don’t think it works.

**Lorentz**

Synthesizes e_{1}, e_{2}, and n,k, and reflectance, for any number of lorenztian oscillators. Provides test data for KK and other programs.

**Critpt**

Performs a least-squares fit of a Critical Point model to (a) Real+Imag Interband Transition Strengths, or (b) Real+Imag Dielectric Constant, or (c) 2nd derivative of Dielectric Constant. Fits a complex function y(x) = C - A*(exp(i*phi))*((x-E)/gamma+i)^n, where C is a baseline constant, and n defines the Critical Point type: n=1/2 for 3D, 0 for 2D, -1/2 for 1D, -1 for Exciton.

**Fresnel**

Using reflectance and transmittance data which display fringes, and film thicknesses, Fresnel calculates the single-surface reflectance and absorption coefficient for the thin film material.

Fresnel capability includes coherent and incoherent calculations of single surface reflectance and absorption coefficient of thin films. Uses Transmittance spectrum + Reflectance spectrum + film thickness. Incoherent substrate allowed.

**Miefit**

Fits spectral data using Mie scattering from homogeneous spheres.

**Kmunk**

Kubelka-Munk processing of diffuse reflectance + transmittance spectra.