Refractive index of GaP-InP (Gallium indium phosphide, GaInP)

import lightsmith as ls

# GaP-InP (Gallium indium phosphide, GaInP): Ferrini et al. 2002: n,k 15.5–124 µm
gap_inp = ls.fetch_refractiveindex("other", "GaP-InP", "Ferrini-far-IR", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(gap_inp.range_nm)  # (15498, 123984) nm
eps = gap_inp.eps([43800])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_2b445f074ca9/lightsmith"
gap_inp = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(gap_inp.source)  # citation and provenance travel with the data

# ... load gap_inp as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=gap_inp)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=15500, stop_nm=124000, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength