Axis Log x Log y

Click the plot to set the calculator wavelength. Note: k data cover 250-1000 nm only; k = 0 elsewhere in the n range 250-1450 nm.

At one wavelength

Refractive index n: 3.96776
Extinction coefficient k: 0.02148

Permittivity ε₁: 15.7427
Permittivity ε₂: 0.170455

Absorption coefficient α: 4593.7 cm⁻¹
Penetration depth δ = λ/(2πk): 4353.79 nm

Abbe number V_d: —
Chromatic dispersion dn/dλ: -2.4 µm⁻¹

Group index n_g: 5.378
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

# Si (Silicon): Green and Keevers 1995: n 0.25–1.45 µm, k 0.25–1.00 µm
si = ls.fetch_refractiveindex("main", "Si", "Green-1995", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(si.range_nm)  # (250, 1450) nm
eps = si.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_f093dd0dcc65/lightsmith"
si = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(si.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (si/green-keevers-1995).

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

300 K (27 °C)

Notes on the source data (kept exactly as published):

k data cover 250-1000 nm only; k = 0 elsewhere in the n range 250-1450 nm

References

M. A. Green and M. J. Keevers. Optical properties of intrinsic silicon at 300 K. Progress in photovoltaics 3, 189-192 (1995)

doi:10.1002/pip.4670030303 Optical properties of intrinsic silicon at 300 K, Progress in Photovoltaics: Research and Applications (1995)

Cite

Martin A. Green and Mark J. Keevers. Optical properties of intrinsic silicon at 300 K. Progress in Photovoltaics: Research and Applications, 3, 189-192 (1995), doi:10.1002/pip.4670030303; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)

Data

Computed on 121 wavelengths, the same grid as the API and the library

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

Si (Silicon), Green and Keevers 1995: n 0.25–1.45 µm, k 0.25–1.00 µm: n and k versus wavelength
λ (µm)	n	k
0.25	1.694	3.666
0.26	1.8	4.072
0.27	2.129	4.69
0.28	3.052	5.258
0.29	4.426	5.16
0.3	5.055	4.128
0.31	5.074	3.559
0.32	5.102	3.269
0.33	5.179	3.085
0.34	5.293	2.951
0.35	5.483	2.904
0.36	6.014	2.912
0.37	6.863	2.051
0.38	6.548	0.885
0.39	5.976	0.465
0.4	5.587	0.303
0.41	5.305	0.22
0.42	5.091	0.167
0.43	4.925	0.134
0.44	4.793	0.109
0.45	4.676	0.091
0.46	4.577	0.077
0.47	4.491	0.064
0.48	4.416	0.057
0.49	4.348	0.05
0.5	4.293	0.045
0.51	4.239	0.039
0.52	4.192	0.036
0.53	4.15	0.033
0.54	4.11	0.03
0.55	4.077	0.028
0.56	4.044	0.026
0.57	4.015	0.024
0.58	3.986	0.023
0.59	3.962	0.021
0.6	3.939	0.02
0.61	3.916	0.018
0.62	3.895	0.017
0.63	3.879	0.016
0.64	3.861	0.015
0.65	3.844	0.015
0.66	3.83	0.014
0.67	3.815	0.013
0.68	3.8	0.012
0.69	3.787	0.011
0.7	3.774	0.011
0.71	3.762	0.011
0.72	3.751	0.01
0.73	3.741	0.009
0.74	3.732	0.008
0.75	3.723	0.008
0.76	3.714	0.007
0.77	3.705	0.007
0.78	3.696	0.006
0.79	3.688	0.006
0.8	3.681	0.005
0.81	3.674	0.005
0.82	3.668	0.005
0.83	3.662	0.004
0.84	3.656	0.004
0.85	3.65	0.004
0.86	3.644	0.003
0.87	3.638	0.003
0.88	3.632	0.003
0.89	3.626	0.002
0.9	3.62	0.002
0.91	3.614	0.002
0.92	3.608	0.002
0.93	3.602	0.002
0.94	3.597	0.001
0.95	3.592	0.001
0.96	3.587	0.001
0.97	3.582	0.001
0.98	3.578	0.001
0.99	3.574	0.001
1	3.57	0.001
1.01	3.566	0
1.02	3.563	0
1.03	3.56	0
1.04	3.557	0
1.05	3.554	0
1.06	3.551	0
1.07	3.548	0
1.08	3.546	0
1.09	3.544	0
1.1	3.541	0
1.11	3.539	0
1.12	3.537	0
1.13	3.534	0
1.14	3.532	0
1.15	3.53	0
1.16	3.528	0
1.17	3.526	0
1.18	3.524	0
1.19	3.522	0
1.2	3.52	0
1.21	3.528	0
1.22	3.516	0
1.23	3.515	0
1.24	3.513	0
1.25	3.511	0
1.26	3.51	0
1.27	3.508	0
1.28	3.507	0
1.29	3.506	0
1.3	3.504	0
1.31	3.503	0
1.32	3.501	0
1.33	3.5	0
1.34	3.498	0
1.35	3.497	0
1.36	3.496	0
1.37	3.495	0
1.38	3.493	0
1.39	3.492	0
1.4	3.491	0
1.41	3.49	0
1.42	3.489	0
1.43	3.488	0
1.44	3.487	0
1.45	3.486	0

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: —

Plot