Refractive index of BK7 (Schott)

import lightsmith as ls

# BK7 (Schott): Lane 1990: n,k 5.00–33.3 µm
bk7 = ls.fetch_refractiveindex("glass", "BK7-Schott", "Lane", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(bk7.range_nm)  # (5000, 33333) nm
eps = bk7.eps([12900])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_daf1888de9bd/lightsmith"
bk7 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(bk7.source)  # citation and provenance travel with the data

# ... load bk7 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=bk7)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=5000, stop_nm=33330, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength