Optical constants

Refractive index of Cr (Chromium)

Johnson and Christy 1974: n,k 0.188–1.937 µm

Data: tabulated nk
Range: 0.188–1.937 µm
Points: 49
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 3.212
Extinction coefficient k: 3.3

Permittivity ε₁: -0.573056
Permittivity ε₂: 21.1992

Absorption coefficient α: 705736 cm⁻¹
Penetration depth δ = λ/(2πk): 28.3392 nm

Abbe number V_d: —
Chromatic dispersion dn/dλ: -1.42857 µm⁻¹

Group index n_g: 4.05143
Group velocity dispersion: — fs²/mm

Dispersion parameter D: — ps/(nm·km)
Photon energy: 2.11001 eV

ε = (n + ik)², α = 4πk/λ, n_g = 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

# Cr (Chromium): Johnson and Christy 1974: n,k 0.188–1.937 µm
cr = ls.fetch_refractiveindex("main", "Cr", "Johnson", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(cr.range_nm)  # (188, 1937) nm
eps = cr.eps([633])  # complex permittivity

Downloads 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_85941b07b712/lightsmith"
cr = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(cr.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (cr/johnson-christy-1974).

# ... load cr as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=cr)],
    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

Same spec runs with DDA, FDTD, BEM or T-matrix: ls.compare(sim, ["mie", "dda"]).

Materials guide Open a sphere of it in Studio Quick start Ask the community

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

Room temperature

References

P. B. Johnson and R. W. Christy. Optical constants of transition metals: Ti, V, Cr, Mn, Fe, Co, Ni, and Pd. Phys. Rev. B 9, 5056-5070 (1974)

doi:10.1103/physrevb.9.5056 Optical constants of transition metals: Ti, V, Cr, Mn, Fe, Co, Ni, and Pd, Physical Review B (1974)

Cite

P. Johnson and R. Christy. Optical constants of transition metals: Ti, V, Cr, Mn, Fe, Co, Ni, and Pd. Physical Review B, 9, 5056-5070 (1974), doi:10.1103/physrevb.9.5056; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)

Data

49 rows as published

CSV comma separated TXT tab separated YAML n, k Full database record original YAML All quantities CSV JSON metadata

Cr (Chromium), Johnson and Christy 1974: n,k 0.188–1.937 µm: n and k versus wavelength
λ (µm)	n	k
0.188	1.28	1.64
0.192	1.31	1.65
0.195	1.35	1.68
0.199	1.39	1.7
0.203	1.43	1.7
0.207	1.46	1.71
0.212	1.46	1.72
0.216	1.47	1.72
0.221	1.45	1.73
0.226	1.43	1.74
0.231	1.4	1.77
0.237	1.38	1.8
0.243	1.36	1.85
0.249	1.36	1.91
0.255	1.37	1.97
0.262	1.38	2.03
0.269	1.39	2.08
0.276	1.43	2.15
0.284	1.45	2.21
0.292	1.48	2.28
0.301	1.53	2.34
0.311	1.58	2.4
0.32	1.65	2.47
0.332	1.69	2.53
0.342	1.76	2.58
0.354	1.84	2.64
0.368	1.87	2.69
0.381	1.92	2.74
0.397	2.0	2.83
0.413	2.08	2.93
0.431	2.19	3.04
0.451	2.33	3.14
0.471	2.51	3.24
0.496	2.75	3.3
0.521	2.94	3.33
0.549	3.18	3.33
0.582	3.22	3.3
0.617	3.17	3.3
0.659	3.09	3.34
0.704	3.05	3.39
0.756	3.08	3.42
0.821	3.2	3.48
0.892	3.3	3.52
0.984	3.41	3.57
1.088	3.58	3.58
1.216	3.67	3.6
1.393	3.69	3.84
1.61	3.66	4.31
1.937	3.71	5.04

Optical transmission calculator

Free-standing sample in vacuum, normal incidence

Transmittance T: —
Reflectance R: —

Fresnel reflection calculator

R_p: —
R_s: —
R = (R_p+R_s)/2: —
Phase φ_p: —
Phase φ_s: —
Brewster angle θ_B: —
Critical angle θ_C: —

Cr (Chromium): all datasets

Experimental data

Models and simulations

About Cr (Chromium)

Chromium (Cr) is a hard, brittle, silver-gray metal that belongs to the transition metals group in the periodic table. It has a body-centered cubic structure and exhibits various oxidation states, but Cr(III) and Cr(VI) are the most stable and commonly observed. Chromium is best known for its role in the production of stainless steel, where it provides corrosion resistance, and in chrome plating for decorative and protective finishes. It is also used in various other alloys to improve hardness and resistance to wear. In specialized applications, chromium compounds are employed as catalysts, pigments, and tanning agents. Of particular note are its magnetic properties, which are exploited in data storage and other magnetic applications. On the environmental front, certain chromium compounds, particularly those in the hexavalent state (Cr(VI)), are highly toxic and carcinogenic, requiring strict handling and disposal protocols. Overall, chromium is an industrially significant metal with a wide range of applications, but its use is tempered by environmental and health considerations.

More about Cr (Chromium) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/Cr/nk/Johnson.yml
ID: ds_85941b07b712
API: /v1/datasets/ds_85941b07b712

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