Optical constants
Refractive index of K (Potassium)
Sutherland and Arakawa 1968: n 0.128–0.313 µm
- Data
- tabulated n
- Range
- 0.128–0.3131 µm
- Points
- 16
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength.
At one wavelength
- Refractive index n
- 0.876
- Extinction coefficient k
- 0
- Permittivity ε1
- 0.767376
- Permittivity ε2
- 0
- Absorption coefficient α
- 0 cm⁻¹
- Penetration depth δ = λ/(2πk)
- — nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- -2.22772 µm⁻¹
- Group index ng
- 1.32154
- Group velocity dispersion
- — fs²/mm
- Dispersion parameter D
- — ps/(nm·km)
- Photon energy
- 6.19921 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
# K (Potassium): Sutherland and Arakawa 1968: n 0.128–0.313 µm
k = ls.fetch_refractiveindex("main", "K", "Sutherland", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(k.range_nm) # (128, 313.1) nm
eps = k.eps([200]) # 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_6fd23c11a52e/lightsmith"
k = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(k.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (k/sutherland-arakawa-1968).
# ... load k as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=k)],
medium_index=1.0,
wavelengths=ls.WavelengthRange(start_nm=128, stop_nm=313, 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:10.1364/josa.58.001080 Optical Properties of Potassium for Photons of Energy 396 to 969 eV*, Journal of the Optical Society of America (1968)
Cite
J. C. Sutherland and E. T. Arakawa. Optical Properties of Potassium for Photons of Energy 396 to 969 eV*. Journal of the Optical Society of America, 58, 1080 (1968), doi:10.1364/josa.58.001080; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)
Data
16 rows as published| λ (µm) | n |
|---|---|
| 0.128 | 0.964 |
| 0.1406 | 0.972 |
| 0.1438 | 0.978 |
| 0.1496 | 0.976 |
| 0.1579 | 0.965 |
| 0.161 | 0.959 |
| 0.1744 | 0.929 |
| 0.1799 | 0.924 |
| 0.1848 | 0.911 |
| 0.1899 | 0.89 |
| 0.2 | 0.876 |
| 0.2101 | 0.845 |
| 0.2198 | 0.823 |
| 0.23 | 0.793 |
| 0.2535 | 0.717 |
| 0.3131 | 0.392 |
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
- —