Refractive index of Si (Silicon)

import lightsmith as ls

# Si (Silicon): Šik et al. 1998: n,k 0.29–0.62 µm; 250 °C
si = ls.fetch_refractiveindex("main", "Si", "Sik-250C", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(si.range_nm)  # (288.3, 619.9) nm
eps = si.eps([423])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_66b9270f1ddf/lightsmith"
si = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(si.source)  # citation and provenance travel with the data

# ... load si as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=si)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=400, stop_nm=619, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength