Optical constants
Refractive index of Na (Sodium)
Smith 1969: n,k 0.313–2.24 µm
- Data
- tabulated nk
- Range
- 0.3125–2.238 µm
- Points
- 23
- State
- solid
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength.
At one wavelength
- Refractive index n
- 0.0540008
- Extinction coefficient k
- 2.42354
- Permittivity ε1
- -5.87065
- Permittivity ε2
- 0.261747
- Absorption coefficient α
- 518297 cm⁻¹
- Penetration depth δ = λ/(2πk)
- 38.5879 nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- -0.11154 µm⁻¹
- Group index ng
- 0.119542
- Group velocity dispersion
- — fs²/mm
- Dispersion parameter D
- — ps/(nm·km)
- Photon energy
- 2.11001 eV
ε = (n + ik)², α = 4πk/λ, ng = n − λ dn/dλ, GVD = λ³/(2πc²) d²n/dλ², D = −(λ/c) d²n/dλ². Group-velocity dispersion is given for formula data only.
Use it in Lightsmith
Load this data in Python, simulate in one more line
pip install lightsmith
import lightsmith as ls
# Na (Sodium): Smith 1969: n,k 0.313–2.24 µm
na = ls.fetch_refractiveindex("main", "Na", "Smith", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(na.range_nm) # (312.539, 2237.98) nm
eps = na.eps([633]) # complex permittivityDownloads the original record once (pinned to the imported snapshot) and caches it.
import json, urllib.request
import lightsmith as ls
url = "https://materials.lightsmith.dev/v1/datasets/ds_0242de265f8f/lightsmith"
na = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(na.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (na/smith-1969).
# ... load na as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=na)],
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 wavelengthSame spec runs with DDA, FDTD, BEM or T-matrix: ls.compare(sim, ["mie", "dda"]).
Lightsmith is open source (MIT): Mie, T-matrix, BEM, DDA, FDTD, RCWA, TMM, mode solvers and inverse design behind one spec, on CPU or GPU. GitHub.
References
- doi:10.1103/physrev.183.634 Optical Constants of Sodium and Potassium from 0.5 to 4.0 eV by Split-Beam Ellipsometry, Physical Review (1969)
Cite
Neville V. Smith. Optical Constants of Sodium and Potassium from 0.5 to 4.0 eV by Split-Beam Ellipsometry. Physical Review, 183, 634-644 (1969), doi:10.1103/physrev.183.634; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)
Data
23 rows as published| λ (µm) | n | k |
|---|---|---|
| 0.312539 | 0.049195 | 1.006191 |
| 0.334099 | 0.05522 | 1.131834 |
| 0.364981 | 0.061078 | 1.326171 |
| 0.386967 | 0.06512 | 1.474192 |
| 0.404648 | 0.06896 | 1.537126 |
| 0.420001 | 0.067744 | 1.631131 |
| 0.439972 | 0.068302 | 1.756891 |
| 0.469993 | 0.066149 | 1.88212 |
| 0.505027 | 0.062846 | 2.068562 |
| 0.545945 | 0.058647 | 2.233705 |
| 0.599827 | 0.052637 | 2.479268 |
| 0.661955 | 0.048526 | 2.761404 |
| 0.750056 | 0.049548 | 3.219077 |
| 0.859807 | 0.053026 | 3.724622 |
| 1.009643 | 0.064101 | 4.352483 |
| 1.175206 | 0.077963 | 5.111368 |
| 1.344731 | 0.098586 | 5.822347 |
| 1.530669 | 0.122821 | 6.668215 |
| 1.689158 | 0.147176 | 7.419681 |
| 1.839528 | 0.175119 | 8.094484 |
| 1.980578 | 0.206644 | 8.800154 |
| 2.119388 | 0.240865 | 9.45135 |
| 2.237982 | 0.262406 | 9.96739 |
Optical transmission calculator
Free-standing sample in vacuum, normal incidence- Transmittance T
- —
- Reflectance R
- —
Fresnel reflection calculator
- Rp
- —
- Rs
- —
- R = (Rp+Rs)/2
- —
- Phase φp
- —
- Phase φs
- —
- Brewster angle θB
- —
- Critical angle θC
- —