Refractive index of Si-Ge (Silicon-germanium, SiGe)

import lightsmith as ls

# Si-Ge (Silicon-germanium, SiGe): Jellison et al. 1993: 98% Si, Si substrate; n,k 0.24–0.84 µm
si_ge = ls.fetch_refractiveindex("other", "Si-Ge", "Jellison-98", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(si_ge.range_nm)  # (240, 840) nm
eps = si_ge.eps([633])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_bd9fedd8cae0/lightsmith"
si_ge = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(si_ge.source)  # citation and provenance travel with the data

# ... load si_ge as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=si_ge)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=400, stop_nm=840, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength