Optical constants
Refractive index of Air
Mathar 2007: n 2.8–4.2 µm
- Data
- tabulated n
- Range
- 2.8–4.2 µm
- Points
- 141
- Temperature
- 288.15 K
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength.
At one wavelength
- Refractive index n
- 1.00027
- Extinction coefficient k
- 0
- Permittivity ε1
- 1.00055
- Permittivity ε2
- 0
- Absorption coefficient α
- 0 cm⁻¹
- Penetration depth δ = λ/(2πk)
- — nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- -1.25750e-07 µm⁻¹
- Group index ng
- 1.00027
- Group velocity dispersion
- — fs²/mm
- Dispersion parameter D
- — ps/(nm·km)
- Photon energy
- 0.36147 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
# Air: Mathar 2007: n 2.8–4.2 µm
air = ls.fetch_refractiveindex("other", "air", "Mathar-2.8", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(air.range_nm) # (2800, 4200) nm
eps = air.eps([3430]) # 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_f082504ac892/lightsmith"
air = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(air.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (air/mathar-2007-2-8).
# ... load air as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=air)],
medium_index=1.0,
wavelengths=ls.WavelengthRange(start_nm=2800, stop_nm=4200, 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
Conditions
- temperature
- 288.15 K
- pressure
- 101325
References
R. J. Mathar.
Refractive index of humid air in the infrared: model fits.
J. Opt. A: Pure Appl. Opt. 9, 470-476 (2007)
[Calculation script (Python) - can be used to calculate the refractive index of air for specific values of humidity, temperature, and pressure]
[Calculation script (Python) - can be used to calculate the refractive index of air for specific values of humidity, temperature, and pressure]
- doi:10.1088/1464-4258/9/5/008 Refractive index of humid air in the infrared: model fits, Journal of Optics A: Pure and Applied Optics (2007)
Cite
Richard J Mathar. Refractive index of humid air in the infrared: model fits. Journal of Optics A: Pure and Applied Optics, 9, 470-476 (2007), doi:10.1088/1464-4258/9/5/008; [Calculation script (Python) - can be used to calculate the refractive index of air for specific values of humidity, temperature, and pressure]; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)
Data
141 rows as published
CSV comma separated
TXT tab separated
YAML n, k
Full database record original YAML
All quantities CSV
JSON metadata
| λ (µm) | n |
|---|---|
| 2.8 | 1.000272874881 |
| 2.81 | 1.000272865477 |
| 2.82 | 1.000272857462 |
| 2.83 | 1.000272850682 |
| 2.84 | 1.000272844993 |
| 2.85 | 1.000272840266 |
| 2.86 | 1.000272836382 |
| 2.87 | 1.000272833232 |
| 2.88 | 1.000272830715 |
| 2.89 | 1.000272828743 |
| 2.9 | 1.000272827234 |
| 2.91 | 1.000272826112 |
| 2.92 | 1.000272825312 |
| 2.93 | 1.000272824772 |
| 2.94 | 1.000272824441 |
| 2.95 | 1.000272824268 |
| 2.96 | 1.000272824211 |
| 2.97 | 1.000272824233 |
| 2.98 | 1.0002728243 |
| 2.99 | 1.000272824384 |
| 3.0 | 1.000272824458 |
| 3.01 | 1.000272824501 |
| 3.02 | 1.000272824495 |
| 3.03 | 1.000272824425 |
| 3.04 | 1.000272824277 |
| 3.05 | 1.000272824042 |
| 3.06 | 1.000272823712 |
| 3.07 | 1.00027282328 |
| 3.08 | 1.000272822744 |
| 3.09 | 1.0002728221 |
| 3.1 | 1.000272821348 |
| 3.11 | 1.000272820488 |
| 3.12 | 1.000272819522 |
| 3.13 | 1.000272818453 |
| 3.14 | 1.000272817284 |
| 3.15 | 1.000272816021 |
| 3.16 | 1.000272814668 |
| 3.17 | 1.00027281323 |
| 3.18 | 1.000272811715 |
| 3.19 | 1.000272810129 |
| 3.2 | 1.000272808479 |
| 3.21 | 1.000272806772 |
| 3.22 | 1.000272805015 |
| 3.23 | 1.000272803217 |
| 3.24 | 1.000272801384 |
| 3.25 | 1.000272799524 |
| 3.26 | 1.000272797644 |
| 3.27 | 1.000272795753 |
| 3.28 | 1.000272793857 |
| 3.29 | 1.000272791962 |
| 3.3 | 1.000272790077 |
| 3.31 | 1.000272788207 |
| 3.32 | 1.00027278636 |
| 3.33 | 1.00027278454 |
| 3.34 | 1.000272782753 |
| 3.35 | 1.000272781005 |
| 3.36 | 1.000272779301 |
| 3.37 | 1.000272777645 |
| 3.38 | 1.000272776042 |
| 3.39 | 1.000272774495 |
| 3.4 | 1.000272773008 |
| 3.41 | 1.000272771583 |
| 3.42 | 1.000272770223 |
| 3.43 | 1.000272768931 |
| 3.44 | 1.000272767708 |
| 3.45 | 1.000272766555 |
| 3.46 | 1.000272765473 |
| 3.47 | 1.000272764462 |
| 3.48 | 1.000272763523 |
| 3.49 | 1.000272762655 |
| 3.5 | 1.000272761857 |
| 3.51 | 1.000272761127 |
| 3.52 | 1.000272760465 |
| 3.53 | 1.000272759867 |
| 3.54 | 1.000272759332 |
| 3.55 | 1.000272758856 |
| 3.56 | 1.000272758437 |
| 3.57 | 1.000272758069 |
| 3.58 | 1.00027275775 |
| 3.59 | 1.000272757474 |
| 3.6 | 1.000272757238 |
| 3.61 | 1.000272757035 |
| 3.62 | 1.000272756861 |
| 3.63 | 1.000272756709 |
| 3.64 | 1.000272756573 |
| 3.65 | 1.000272756447 |
| 3.66 | 1.000272756324 |
| 3.67 | 1.000272756197 |
| 3.68 | 1.000272756058 |
| 3.69 | 1.0002727559 |
| 3.7 | 1.000272755715 |
| 3.71 | 1.000272755494 |
| 3.72 | 1.00027275523 |
| 3.73 | 1.000272754913 |
| 3.74 | 1.000272754535 |
| 3.75 | 1.000272754087 |
| 3.76 | 1.000272753558 |
| 3.77 | 1.00027275294 |
| 3.78 | 1.000272752223 |
| 3.79 | 1.000272751396 |
| 3.8 | 1.000272750451 |
| 3.81 | 1.000272749376 |
| 3.82 | 1.000272748161 |
| 3.83 | 1.000272746795 |
| 3.84 | 1.000272745269 |
| 3.85 | 1.00027274357 |
| 3.86 | 1.000272741688 |
| 3.87 | 1.000272739612 |
| 3.88 | 1.000272737331 |
| 3.89 | 1.000272734833 |
| 3.9 | 1.000272732107 |
| 3.91 | 1.000272729141 |
| 3.92 | 1.000272725925 |
| 3.93 | 1.000272722445 |
| 3.94 | 1.000272718691 |
| 3.95 | 1.000272714652 |
| 3.96 | 1.000272710314 |
| 3.97 | 1.000272705666 |
| 3.98 | 1.000272700697 |
| 3.99 | 1.000272695394 |
| 4.0 | 1.000272689746 |
| 4.01 | 1.00027268374 |
| 4.02 | 1.000272677365 |
| 4.03 | 1.000272670608 |
| 4.04 | 1.000272663458 |
| 4.05 | 1.000272655903 |
| 4.06 | 1.000272647931 |
| 4.07 | 1.000272639529 |
| 4.08 | 1.000272630686 |
| 4.09 | 1.00027262139 |
| 4.1 | 1.00027261163 |
| 4.11 | 1.000272601392 |
| 4.12 | 1.000272590666 |
| 4.13 | 1.00027257944 |
| 4.14 | 1.000272567702 |
| 4.15 | 1.00027255544 |
| 4.16 | 1.000272542643 |
| 4.17 | 1.000272529299 |
| 4.18 | 1.000272515396 |
| 4.19 | 1.000272500924 |
| 4.2 | 1.000272485871 |
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
- —
Dry air at 15 °C, 101.325 kPa, 370 ppm CO2 content.