Optical constants

Refractive index of BK7 matching liquid (Cargille)

BK7 matching liquid: n,k 0.35–1.55 µm

Data: formula 5 + tabulated k
Range: 0.35–1.55 µm
Temperature: 298 K
State: liquid
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.51681
Extinction coefficient k: 0

Permittivity ε₁: 2.30072
Permittivity ε₂: 0

Absorption coefficient α: 0 cm⁻¹
Penetration depth δ = λ/(2πk): — nm

Abbe number V_d: 52.795
Chromatic dispersion dn/dλ: -0.050056 µm⁻¹

Group index n_g: 1.54622
Group velocity dispersion: 96.2622 fs²/mm

Dispersion parameter D: -525.161 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

# BK7 matching liquid (Cargille): BK7 matching liquid
mat = ls.fetch_refractiveindex("specs", "Cargille", "BK7_matching_liquid", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(mat.range_nm)  # (350, 1550) nm
eps = mat.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_ec6df37d1182/lightsmith"
mat = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(mat.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (cargille-bk7-matching-liquid/cargille).

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

Dispersion formula

Cauchy (formula 5), λ in µm

n = 1.502639 + 0.004708942 λ^{- 2.0} + 6.367045 \times 10^{-5} λ^{- 4.0}

Valid from 0.35 to 1.55 µm.

Coefficients as stored

C_i	Value
C1	1.502639
C2	0.004708942
C3	-2.0
C4	6.367045e-05
C5	-4.0

Comments and conditions

25 °C

Conditions

temperature: 298 K

Properties

density: value: 1322, temperature: 298
thermal expansion: value: 0.0007, temperature: 298
freezing point: value: 264

References

BK-7 Matching Liquid Data Sheet 27-March-2023 (obtained from https://www.cargille.com)

Cite

BK-7 Matching Liquid Data Sheet 27-March-2023 (obtained from https://www.cargille.com); Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)

Data

Computed on 413 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

BK7 matching liquid (Cargille), BK7 matching liquid: n and k versus wavelength
λ (µm)	n	k
0.35	1.545322	1.243000e-05
0.351308	1.544974	1.151186e-05
0.35262	1.544628	1.059029e-05
0.353938	1.544286	9.665275e-06
0.35526	1.543947	8.736804e-06
0.356588	1.54361	7.804864e-06
0.35792	1.543277	6.869442e-06
0.359258	1.542946	5.930525e-06
0.3606	1.542618	4.988100e-06
0.361947	1.542293	4.042153e-06
0.3633	1.541971	3.092672e-06
0.364657	1.541652	2.139643e-06
0.365	1.541572	1.899000e-06
0.36602	1.541336	1.863665e-06
0.367387	1.541022	1.816277e-06
0.36876	1.540711	1.768712e-06
0.370138	1.540403	1.720969e-06
0.371521	1.540097	1.673048e-06
0.372909	1.539794	1.624948e-06
0.374303	1.539493	1.576668e-06
0.375701	1.539196	1.528207e-06
0.377105	1.5389	1.479566e-06
0.378514	1.538608	1.430742e-06
0.379928	1.538318	1.381737e-06
0.381348	1.53803	1.332548e-06
0.382773	1.537745	1.283175e-06
0.384203	1.537462	1.233618e-06
0.385639	1.537182	1.183876e-06
0.387079	1.536904	1.133948e-06
0.388526	1.536628	1.083833e-06
0.389978	1.536355	1.033532e-06
0.391435	1.536084	9.830418e-07
0.392897	1.535816	9.323633e-07
0.394365	1.535549	8.814955e-07
0.395839	1.535285	8.304376e-07
0.397318	1.535024	7.791889e-07
0.398802	1.534764	7.277487e-07
0.400293	1.534507	6.761163e-07
0.401788	1.534252	6.242910e-07
0.40329	1.533999	5.722721e-07
0.4047	1.533764	5.234000e-07
0.404796	1.533748	5.228787e-07
0.406309	1.533499	5.147015e-07
0.407827	1.533253	5.064937e-07
0.409351	1.533008	4.982552e-07
0.41088	1.532766	4.899860e-07
0.412416	1.532525	4.816859e-07
0.413957	1.532287	4.733548e-07
0.415503	1.532051	4.649925e-07
0.417056	1.531816	4.565990e-07
0.418614	1.531584	4.481741e-07
0.420178	1.531354	4.397178e-07
0.421748	1.531125	4.312299e-07
0.423324	1.530899	4.227102e-07
0.424906	1.530674	4.141587e-07
0.426494	1.530451	4.055753e-07
0.428087	1.53023	3.969597e-07
0.429687	1.530011	3.883120e-07
0.431292	1.529794	3.796320e-07
0.432904	1.529579	3.709196e-07
0.434521	1.529365	3.621746e-07
0.436145	1.529154	3.533969e-07
0.437775	1.528944	3.445864e-07
0.43941	1.528735	3.357430e-07
0.441052	1.528529	3.268665e-07
0.4427	1.528324	3.179569e-07
0.444354	1.528121	3.090140e-07
0.446015	1.527919	3.000377e-07
0.447681	1.52772	2.910279e-07
0.449354	1.527522	2.819843e-07
0.451033	1.527325	2.729070e-07
0.452718	1.52713	2.637958e-07
0.45441	1.526937	2.546505e-07
0.456108	1.526746	2.454711e-07
0.457812	1.526556	2.362573e-07
0.459522	1.526367	2.270092e-07
0.461239	1.52618	2.177264e-07
0.462963	1.525995	2.084090e-07
0.464693	1.525811	1.990568e-07
0.466429	1.525629	1.896696e-07
0.468172	1.525448	1.802474e-07
0.469921	1.525269	1.707899e-07
0.471677	1.525091	1.612972e-07
0.473439	1.524915	1.517689e-07
0.475208	1.52474	1.422050e-07
0.476984	1.524566	1.326054e-07
0.478766	1.524394	1.229700e-07
0.48	1.524277	1.163000e-07
0.480555	1.524224	1.128279e-07
0.482351	1.524055	1.015981e-07
0.484153	1.523887	9.032639e-08
0.485962	1.52372	7.901255e-08
0.4861	1.523708	7.815000e-08
0.487778	1.523555	7.596458e-08
0.4896	1.523392	7.359067e-08
0.49143	1.523229	7.120790e-08
0.493266	1.523068	6.881623e-08
0.495109	1.522908	6.641562e-08
0.496959	1.52275	6.400604e-08
0.498816	1.522593	6.158746e-08
0.50068	1.522437	5.915984e-08
0.502551	1.522282	5.672315e-08
0.504428	1.522129	5.427735e-08
0.506313	1.521977	5.182242e-08
0.508205	1.521826	4.935831e-08
0.510104	1.521676	4.688500e-08
0.51201	1.521528	4.440244e-08
0.513923	1.521381	4.191061e-08
0.515843	1.521235	3.940947e-08
0.517771	1.52109	3.689898e-08
0.519705	1.520946	3.437911e-08
0.521647	1.520804	3.184983e-08
0.523596	1.520662	2.931110e-08
0.525553	1.520522	2.676288e-08
0.527516	1.520383	2.420513e-08
0.529487	1.520245	2.163784e-08
0.531466	1.520108	1.906095e-08
0.533452	1.519973	1.647443e-08
0.535445	1.519838	1.387824e-08
0.537446	1.519705	1.127236e-08
0.539454	1.519572	8.656736e-09
0.541469	1.519441	6.031341e-09
0.543493	1.51931	3.396137e-09
0.545523	1.519181	7.510863e-10
0.5461	1.519145	0
0.547562	1.519053	0
0.549608	1.518926	0
0.551661	1.5188	0
0.553723	1.518674	0
0.555791	1.51855	0
0.557868	1.518427	0
0.559953	1.518305	0
0.562045	1.518184	0
0.564145	1.518064	0
0.566253	1.517944	0
0.568369	1.517826	0
0.570492	1.517709	0
0.572624	1.517592	0
0.574764	1.517477	0
0.576911	1.517362	0
0.579067	1.517248	0
0.58123	1.517136	0
0.583402	1.517024	0
0.585582	1.516913	0
0.58777	1.516803	0
0.5893	1.516727	0
0.589966	1.516694	0
0.592171	1.516585	0
0.594383	1.516478	0
0.596604	1.516371	0
0.598833	1.516266	0
0.601071	1.516161	0
0.603317	1.516057	0
0.605571	1.515953	0
0.607834	1.515851	0
0.610105	1.515749	0
0.612385	1.515648	0
0.614673	1.515548	0
0.61697	1.515449	0
0.619275	1.515351	0
0.621589	1.515253	0
0.623911	1.515156	0
0.626243	1.51506	0
0.628582	1.514965	0
0.630931	1.51487	0
0.6328	1.514796	0
0.633289	1.514776	0
0.635655	1.514683	0
0.63803	1.514591	0
0.640414	1.514499	0
0.642807	1.514408	0
0.6439	1.514367	0
0.645209	1.514318	0
0.64762	1.514228	0
0.650039	1.51414	0
0.652468	1.514052	0
0.654906	1.513964	0
0.6563	1.513915	0
0.657353	1.513877	0
0.659809	1.513791	0
0.662275	1.513706	0
0.664749	1.513621	0
0.667233	1.513537	0
0.669726	1.513454	0
0.672229	1.513371	0
0.67474	1.513289	0
0.677262	1.513208	0
0.679792	1.513127	0
0.682332	1.513047	0
0.684882	1.512967	0
0.687441	1.512889	0
0.690009	1.51281	0
0.692588	1.512733	0
0.6943	1.512682	0
0.695175	1.512656	0
0.697773	1.512579	0
0.70038	1.512503	0
0.702997	1.512428	0
0.705624	1.512353	0
0.70826	1.512279	0
0.710907	1.512206	0
0.713563	1.512133	0
0.716229	1.51206	0
0.718905	1.511989	0
0.721592	1.511917	0
0.724288	1.511847	0
0.726994	1.511777	0
0.729711	1.511707	0
0.732437	1.511638	0
0.735174	1.511569	0
0.737921	1.511501	0
0.740678	1.511434	0
0.743446	1.511367	0
0.746223	1.511301	0
0.749012	1.511235	0
0.75181	1.511169	0
0.754619	1.511105	0
0.757439	1.51104	0
0.760269	1.510976	0
0.76311	1.510913	0
0.765961	1.51085	0
0.768823	1.510788	0
0.771696	1.510726	0
0.774579	1.510664	0
0.777474	1.510604	0
0.780379	1.510543	0
0.783294	1.510483	0
0.786221	1.510424	0
0.789159	1.510364	0
0.792108	1.510306	0
0.795067	1.510248	0
0.798038	1.51019	0
0.80102	1.510133	0
0.804013	1.510076	0
0.807017	1.510019	0
0.810032	1.509963	0
0.813059	1.509908	0
0.816097	1.509853	0
0.819146	1.509798	0
0.822207	1.509744	0
0.825279	1.50969	0
0.828363	1.509637	0
0.831458	1.509584	0
0.834565	1.509531	0
0.837683	1.509479	0
0.84	1.509441	0
0.840813	1.509427	6.193032e-10
0.843955	1.509376	3.011900e-09
0.847108	1.509325	5.413438e-09
0.850274	1.509274	7.823948e-09
0.853451	1.509224	1.024347e-08
0.856639	1.509174	1.267202e-08
0.85984	1.509125	1.510966e-08
0.863053	1.509076	1.755640e-08
0.866278	1.509027	2.001228e-08
0.869515	1.508979	2.247734e-08
0.872764	1.508931	2.495161e-08
0.876025	1.508883	2.743512e-08
0.879298	1.508836	2.992791e-08
0.882583	1.508789	3.243002e-08
0.885881	1.508743	3.494148e-08
0.889191	1.508697	3.746232e-08
0.892514	1.508651	3.999258e-08
0.895848	1.508605	4.253230e-08
0.899196	1.50856	4.508150e-08
0.902556	1.508516	4.764023e-08
0.905928	1.508471	5.020852e-08
0.909313	1.508427	5.278641e-08
0.912711	1.508383	5.537393e-08
0.916121	1.50834	5.797111e-08
0.919544	1.508297	6.057800e-08
0.92298	1.508254	6.319463e-08
0.926429	1.508212	6.582104e-08
0.92989	1.50817	6.845727e-08
0.933365	1.508128	7.110334e-08
0.936852	1.508087	7.375930e-08
0.940353	1.508046	7.642518e-08
0.943866	1.508005	7.910103e-08
0.947393	1.507964	8.178687e-08
0.950933	1.507924	8.448275e-08
0.954486	1.507884	8.718870e-08
0.958053	1.507845	8.990476e-08
0.961632	1.507806	9.263097e-08
0.965225	1.507767	9.536737e-08
0.968832	1.507728	9.811399e-08
0.972452	1.50769	1.008709e-07
0.976085	1.507652	1.036381e-07
0.979733	1.507614	1.064156e-07
0.983393	1.507576	1.092035e-07
0.987068	1.507539	1.120018e-07
0.990756	1.507502	1.148106e-07
0.994458	1.507466	1.176299e-07
0.998174	1.507429	1.204597e-07
1.0019	1.507393	1.233000e-07
1.00565	1.507357	1.261510e-07
1.0094	1.507322	1.290127e-07
1.01318	1.507287	1.318850e-07
1.01696	1.507252	1.347681e-07
1.02076	1.507217	1.376619e-07
1.02458	1.507183	1.405666e-07
1.0284	1.507148	1.434821e-07
1.03225	1.507114	1.464085e-07
1.0361	1.507081	1.493458e-07
1.03997	1.507047	1.522941e-07
1.04386	1.507014	1.552535e-07
1.04776	1.506981	1.582238e-07
1.05168	1.506949	1.612053e-07
1.05561	1.506916	1.641979e-07
1.05955	1.506884	1.672018e-07
1.06351	1.506852	1.702168e-07
1.0648	1.506842	1.712000e-07
1.06748	1.50682	1.752994e-07
1.07147	1.506789	1.813942e-07
1.07547	1.506758	1.875119e-07
1.07949	1.506727	1.936524e-07
1.08353	1.506696	1.998158e-07
1.08758	1.506666	2.060023e-07
1.09164	1.506635	2.122119e-07
1.09572	1.506605	2.184447e-07
1.09981	1.506576	2.247008e-07
1.10392	1.506546	2.309802e-07
1.10805	1.506517	2.372831e-07
1.11219	1.506487	2.436096e-07
1.11634	1.506459	2.499597e-07
1.12051	1.50643	2.563335e-07
1.1247	1.506401	2.627312e-07
1.1289	1.506373	2.691527e-07
1.13312	1.506345	2.755983e-07
1.13735	1.506317	2.820679e-07
1.1416	1.50629	2.885617e-07
1.14587	1.506262	2.950798e-07
1.15015	1.506235	3.016222e-07
1.15445	1.506208	3.081891e-07
1.15876	1.506181	3.147805e-07
1.16309	1.506155	3.213965e-07
1.16744	1.506128	3.280373e-07
1.1718	1.506102	3.347029e-07
1.17618	1.506076	3.413933e-07
1.18057	1.50605	3.481088e-07
1.18498	1.506025	3.548494e-07
1.18941	1.505999	3.616151e-07
1.19386	1.505974	3.684062e-07
1.19832	1.505949	3.752226e-07
1.20279	1.505924	3.820644e-07
1.20729	1.5059	3.889319e-07
1.2118	1.505875	3.958250e-07
1.21633	1.505851	4.027438e-07
1.22087	1.505827	4.096885e-07
1.22543	1.505803	4.166592e-07
1.23001	1.505779	4.236559e-07
1.23461	1.505756	4.306788e-07
1.23922	1.505732	4.377278e-07
1.24385	1.505709	4.448033e-07
1.2485	1.505686	4.519051e-07
1.25317	1.505663	4.590335e-07
1.25785	1.505641	4.661886e-07
1.26255	1.505618	4.733703e-07
1.26727	1.505596	4.805789e-07
1.272	1.505574	4.878145e-07
1.27675	1.505552	4.950770e-07
1.28152	1.50553	5.023668e-07
1.28631	1.505508	5.096837e-07
1.29112	1.505487	5.170280e-07
1.29594	1.505465	5.243997e-07
1.3	1.505448	5.306000e-07
1.30078	1.505444	5.328830e-07
1.30565	1.505423	5.470247e-07
1.31052	1.505402	5.612192e-07
1.31542	1.505382	5.754668e-07
1.32034	1.505361	5.897676e-07
1.32527	1.505341	6.041218e-07
1.33022	1.505321	6.185297e-07
1.33519	1.5053	6.329914e-07
1.34018	1.505281	6.475072e-07
1.34519	1.505261	6.620772e-07
1.35021	1.505241	6.767016e-07
1.35526	1.505222	6.913806e-07
1.36032	1.505202	7.061146e-07
1.36541	1.505183	7.209035e-07
1.37051	1.505164	7.357477e-07
1.37563	1.505145	7.506474e-07
1.38077	1.505126	7.656028e-07
1.38593	1.505108	7.806140e-07
1.39111	1.505089	7.956814e-07
1.3963	1.505071	8.108050e-07
1.40152	1.505053	8.259851e-07
1.40676	1.505035	8.412220e-07
1.41201	1.505017	8.565158e-07
1.41729	1.504999	8.718667e-07
1.42259	1.504981	8.872750e-07
1.4279	1.504964	9.027409e-07
1.43324	1.504946	9.182646e-07
1.43859	1.504929	9.338462e-07
1.44397	1.504912	9.494861e-07
1.44936	1.504895	9.651844e-07
1.45478	1.504878	9.809414e-07
1.46021	1.504861	9.967572e-07
1.46567	1.504845	1.012632e-06
1.47115	1.504828	1.028566e-06
1.47664	1.504812	1.044560e-06
1.48216	1.504796	1.060614e-06
1.4877	1.50478	1.076727e-06
1.49326	1.504764	1.092901e-06
1.49884	1.504748	1.109135e-06
1.50444	1.504732	1.125430e-06
1.51006	1.504716	1.141786e-06
1.5157	1.504701	1.158203e-06
1.52136	1.504685	1.174681e-06
1.52705	1.50467	1.191221e-06
1.53275	1.504655	1.207822e-06
1.53848	1.50464	1.224486e-06
1.54423	1.504625	1.241212e-06
1.55	1.50461	1.258000e-06

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: —

BK7 matching liquid (Cargille): all datasets

BK7 matching liquid n,k 0.35–1.55 µm default

About BK7 matching liquid (Cargille)

An index-matching material is usually used to create an optical contact with minimum reflection between optical components.

Index-matching material - Wikipedia

More about BK7 matching liquid (Cargille) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/specs/cargille/index-matching liquids/nk/BK7_matching_liquid.yml
ID: ds_ec6df37d1182
API: /v1/datasets/ds_ec6df37d1182

Plot