Julia package for reading optical data from refractiveindex.info.
Say we are interested in the refractive index of Au (chemical formula for gold). With ri_search, we search the refractiveindex.info database for matches:
using OpticalConstants
matches = ri_search("Au")
println(matches)
The matches are returned as a vector of dictionaries (only a few of the keys are shown to save space):
[{"material" => "Au", "name" => "Johnson and Christy 1972: n,k 0.188-1.937 µm", "page" => "Johnson", ...}, {"material" => "Au", "name" => "McPeak et al. 2015: n,k 0.3-1.7 µm", "page" => "McPeak", ...}, ...]
From this list, we simply select the source(s) that we want. It's possible to narrow the search by providing an optional page argument during the search, e.g. ri_search("Au", "Johnson").
Reading the optical constants of a material is done using load_ri, which accepts one or several dictionaries returned from ri_search. To load the optical constants of gold (Au) from Johnson and Christie, do
Au = load_ri(ri_search("Au", "Johnson"))
println(Au)
which displays
Au, Tabulated n-k (0.1879 - 1.937 μm); interpolation: Dierckx.Spline1D.
Ref: P. B. Johnson and R. W. Christy. Optical constants of the noble metals, <a href="https://doi.org/10.1103/PhysRevB.6.4370"><i>Phys. Rev. B</i> <b>6</b>, 4370-4379 (1972)</a>.
Comments: Room temperature.
The description tells us that the refractive index data of gold is tabulated, but interpolated using Spline1D from the Dierckx package.
The real and imaginary parts of the complex refractive index of a material is obtained by calling get_ri and get_ec, respectively. As an example, let's gather 200 points of the complex refractive index equally spaced on the tabulated domain of Johnson and Christies measurements of gold (0.1879 - 1.937 μm).
λ = LinRange(bounds(Au)..., 200)
ri = get_ri(Au, λ)
ec = get_ec(Au, λ)
complex_n = ri .+ im*ec
The data from refractiveindex.info assumes that wavelengths are supplied in μm. We can change this to, say nm, in the following way:
set_unit_length(Units.nm)
println(bounds(Au))
The print statement now yields
[187.9, 1937.0]