Optical constants
Refractive index of (C2H4)n (Polyethylene, PE, HDPE, LDPE)
Smith and Loewenstein 1975: HDPE; n,k 40.0–200 µm
- Data
- tabulated nk
- Range
- 40–200 µm
- Points
- 21
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength.
At one wavelength
- Refractive index n
- 1.52
- Extinction coefficient k
- 0.0017
- Permittivity ε1
- 2.3104
- Permittivity ε2
- 0.005168
- Absorption coefficient α
- 2.38958 cm⁻¹
- Penetration depth δ = λ/(2πk)
- 8.36968e+06 nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- 0 µm⁻¹
- Group index ng
- 1.52
- Group velocity dispersion
- — fs²/mm
- Dispersion parameter D
- — ps/(nm·km)
- Photon energy
- 0.0138685 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
# (C2H4)n (Polyethylene, PE, HDPE, LDPE): Smith and Loewenstein 1975: HDPE; n,k 40.0–200 µm
polyethylene = ls.fetch_refractiveindex("organic", "polyethylene", "Smith", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(polyethylene.range_nm) # (40000, 200000) nm
eps = polyethylene.eps([89400]) # 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_c28346138acb/lightsmith"
polyethylene = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(polyethylene.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (polyethylene/smith-loewenstein-1975).
# ... load polyethylene as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=polyethylene)],
medium_index=1.0,
wavelengths=ls.WavelengthRange(start_nm=40000, stop_nm=200000, 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.
Comments and conditions
References
- doi:10.1364/ao.14.001335 Optical constants of far infrared materials 3: plastics, Applied Optics (1975)
Cite
Donald R. Smith and Ernest V. Loewenstein. Optical constants of far infrared materials 3: plastics. Applied Optics, 14, 1335 (1975), doi:10.1364/ao.14.001335; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)
Data
21 rows as published| λ (µm) | n | k |
|---|---|---|
| 40.0 | 1.519 | 0.002 |
| 41.6667 | 1.519 | 0.0024 |
| 43.4783 | 1.519 | 0.0027 |
| 45.4545 | 1.52 | 0.0029 |
| 47.619 | 1.521 | 0.0027 |
| 50.0 | 1.521 | 0.0024 |
| 52.6316 | 1.521 | 0.0023 |
| 55.5556 | 1.521 | 0.0021 |
| 58.8235 | 1.521 | 0.002 |
| 62.5 | 1.521 | 0.0019 |
| 66.6667 | 1.521 | 0.0019 |
| 71.4286 | 1.521 | 0.0018 |
| 76.9231 | 1.52 | 0.0018 |
| 83.3333 | 1.52 | 0.0017 |
| 90.9091 | 1.52 | 0.0017 |
| 100.0 | 1.521 | 0.0016 |
| 111.1111 | 1.521 | 0.0016 |
| 125.0 | 1.521 | 0.0017 |
| 142.8571 | 1.521 | 0.0018 |
| 166.6667 | 1.519 | 0.0019 |
| 200.0 | 1.518 | 0.0022 |
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
- —
HDPE. Measured using approximately 1 mm thick film.