Refractive index of SiO₂ (Silicon dioxide, Silica, Quartz)

import lightsmith as ls

# SiO2 (Silicon dioxide, Silica, Quartz): Popova et al. 1972: n,k 7–50 µm
sio2 = ls.fetch_refractiveindex("main", "SiO2", "Popova", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(sio2.range_nm)  # (7000, 50000) nm
eps = sio2.eps([18700])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_a70299d6f935/lightsmith"
sio2 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(sio2.source)  # citation and provenance travel with the data

# ... load sio2 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=sio2)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=7000, stop_nm=50000, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength