Refractive index of Si₃N₄, SiN (Silicon nitride)

import lightsmith as ls

# Si3N4, SiN (Silicon nitride): Kischkat et al. 2012: Non-stoichiometric SiN; n,k 1.54–14.29 µm
si3n4_sin = ls.fetch_refractiveindex("main", "Si3N4", "Kischkat", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(si3n4_sin.range_nm)  # (1538.46, 14285.7) nm
eps = si3n4_sin.eps([4690])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_61c88bd231e9/lightsmith"
si3n4_sin = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(si3n4_sin.source)  # citation and provenance travel with the data

# ... load si3n4_sin as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=si3n4_sin)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=1539, stop_nm=14280, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength