Refractive index of WSe₂ (Tungsten diselenide)

import lightsmith as ls

# WSe2 (Tungsten diselenide): Gu et al. 2019: 2-layer (2L) film; n,k 0.193–1.69 µm
wse2 = ls.fetch_refractiveindex("main", "WSe2", "Gu-2L", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(wse2.range_nm)  # (193, 1690) nm
eps = wse2.eps([633])  # complex permittivity

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_2255c384a7be/lightsmith"
wse2 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(wse2.source)  # citation and provenance travel with the data

# ... load wse2 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=wse2)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=400, stop_nm=1000, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength