Optical constants

Refractive index of BAK2 (HIKARI)

BAK2: n,k 0.4–0.7 µm

Data: formula 3 + tabulated k
Range: 0.4–0.7 µm
Temperature: 293 K
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.53996
Extinction coefficient k: 4.67830e-09

Permittivity ε₁: 2.37147
Permittivity ε₂: 1.44088e-08

Absorption coefficient α: 0.0010005 cm⁻¹
Penetration depth δ = λ/(2πk): 1.99901e+10 nm

Abbe number V_d: 59.682
Chromatic dispersion dn/dλ: -0.0467489 µm⁻¹

Group index n_g: 1.56743
Group velocity dispersion: 81.1252 fs²/mm

Dispersion parameter D: -442.581 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

# BAK2 (HIKARI): BAK2
hikari_bak2 = ls.fetch_refractiveindex("specs", "HIKARI-optical", "BAK2", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(hikari_bak2.range_nm)  # (400, 700) nm
eps = hikari_bak2.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_99136e58feda/lightsmith"
hikari_bak2 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(hikari_bak2.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (hikari-bak2/hikari).

# ... load hikari_bak2 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=hikari_bak2)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=400, stop_nm=700, 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

Polynomial (formula 3), λ in µm

n^{2} = 2.319725 + 0.002602493 λ^{2.0} + 0.02249807 λ^{- 2.0} - 0.002672041 λ^{- 4.0} + 0.0003926686 λ^{- 6.0} - 2.043303 \times 10^{-5} λ^{- 8.0}

Valid from 0.4 to 0.7 µm.

Coefficients as stored

C_i	Value
C1	2.319725
C2	0.002602493
C3	2.0
C4	0.02249807
C5	-2.0
C6	-0.002672041
C7	-4.0
C8	0.0003926686
C9	-6.0
C10	-2.043303e-05
C11	-8.0

Comments and conditions

Conditions

temperature: 293 K

Properties

nd: 1.539960
Vd: 59.681919
glass code: 540597
glass status: preferred
density: value: 2850
thermal expansion: value: 9.7e-06, temperature range: 243 343
dPgF: 0.0021

References

NIKON Zemax catalog 2017-11 (obtained from http://www.nikon.com)
See also HIKARI glass data sheets

Cite

NIKON Zemax catalog 2017-11 (obtained from http://www.nikon.com); See also HIKARI glass data sheets; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)

Data

Computed on 408 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

BAK2 (HIKARI), BAK2: n and k versus wavelength
λ (µm)	n	k
0.4	1.555977	3.184700e-09
0.400561	1.555893	3.189169e-09
0.401124	1.555808	3.193644e-09
0.401687	1.555723	3.198125e-09
0.40225	1.555639	3.202613e-09
0.402815	1.555555	3.207107e-09
0.40338	1.555471	3.211607e-09
0.403946	1.555388	3.216114e-09
0.404513	1.555304	3.220627e-09
0.405081	1.555221	3.225146e-09
0.40565	1.555138	3.229672e-09
0.406219	1.555055	3.234204e-09
0.406789	1.554973	3.238742e-09
0.40736	1.554891	3.243287e-09
0.407932	1.554809	3.247838e-09
0.408504	1.554727	3.252395e-09
0.409078	1.554645	3.256959e-09
0.409652	1.554564	3.261529e-09
0.410227	1.554483	3.266106e-09
0.410803	1.554402	3.270689e-09
0.411379	1.554321	3.275279e-09
0.411957	1.554241	3.279875e-09
0.412535	1.55416	3.284477e-09
0.413114	1.55408	3.289086e-09
0.413694	1.554	3.293701e-09
0.414274	1.553921	3.298323e-09
0.414856	1.553842	3.302951e-09
0.415438	1.553762	3.307586e-09
0.416021	1.553684	3.312227e-09
0.416605	1.553605	3.316875e-09
0.41719	1.553526	3.321530e-09
0.417775	1.553448	3.326191e-09
0.418362	1.55337	3.330858e-09
0.418949	1.553292	3.335532e-09
0.419537	1.553215	3.340212e-09
0.42	1.553154	3.343900e-09
0.420126	1.553138	3.344900e-09
0.420715	1.553061	3.349597e-09
0.421306	1.552984	3.354300e-09
0.421897	1.552907	3.359010e-09
0.422489	1.552831	3.363726e-09
0.423082	1.552754	3.368449e-09
0.423676	1.552678	3.373179e-09
0.424271	1.552603	3.377915e-09
0.424866	1.552527	3.382658e-09
0.425462	1.552452	3.387408e-09
0.42606	1.552377	3.392164e-09
0.426658	1.552302	3.396927e-09
0.427256	1.552227	3.401697e-09
0.427856	1.552153	3.406473e-09
0.428457	1.552079	3.411256e-09
0.429058	1.552005	3.416046e-09
0.42966	1.551931	3.420843e-09
0.430263	1.551858	3.425646e-09
0.430867	1.551784	3.430456e-09
0.431472	1.551711	3.435272e-09
0.432077	1.551639	3.440096e-09
0.432684	1.551566	3.444926e-09
0.433291	1.551494	3.449763e-09
0.433899	1.551421	3.454607e-09
0.434508	1.551349	3.459458e-09
0.435118	1.551278	3.464315e-09
0.435729	1.551206	3.469179e-09
0.43634	1.551135	3.474050e-09
0.436953	1.551064	3.478928e-09
0.437566	1.550993	3.483813e-09
0.43818	1.550922	3.488705e-09
0.438795	1.550852	3.493603e-09
0.439411	1.550782	3.498508e-09
0.44	1.550715	3.503200e-09
0.440028	1.550712	3.503420e-09
0.440645	1.550642	3.508336e-09
0.441264	1.550572	3.513259e-09
0.441883	1.550503	3.518189e-09
0.442503	1.550434	3.523126e-09
0.443124	1.550365	3.528070e-09
0.443746	1.550296	3.533020e-09
0.444369	1.550228	3.537978e-09
0.444993	1.550159	3.542942e-09
0.445617	1.550091	3.547914e-09
0.446243	1.550023	3.552892e-09
0.446869	1.549956	3.557878e-09
0.447496	1.549888	3.562870e-09
0.448124	1.549821	3.567870e-09
0.448753	1.549754	3.572876e-09
0.449383	1.549687	3.577890e-09
0.450014	1.549621	3.582910e-09
0.450645	1.549554	3.587938e-09
0.451278	1.549488	3.592973e-09
0.451911	1.549422	3.598014e-09
0.452546	1.549356	3.603063e-09
0.453181	1.54929	3.608119e-09
0.453817	1.549225	3.613182e-09
0.454454	1.54916	3.618252e-09
0.455092	1.549095	3.623329e-09
0.45573	1.54903	3.628414e-09
0.45637	1.548965	3.633505e-09
0.457011	1.548901	3.638604e-09
0.457652	1.548837	3.643709e-09
0.458294	1.548773	3.648822e-09
0.458938	1.548709	3.653943e-09
0.459582	1.548645	3.659070e-09
0.46	1.548604	3.662400e-09
0.460227	1.548582	3.664204e-09
0.460873	1.548519	3.669346e-09
0.461519	1.548456	3.674495e-09
0.462167	1.548393	3.679651e-09
0.462816	1.54833	3.684814e-09
0.463465	1.548268	3.689985e-09
0.464116	1.548206	3.695163e-09
0.464767	1.548144	3.700348e-09
0.46542	1.548082	3.705541e-09
0.466073	1.54802	3.710740e-09
0.466727	1.547958	3.715947e-09
0.467382	1.547897	3.721162e-09
0.468038	1.547836	3.726383e-09
0.468695	1.547775	3.731612e-09
0.469353	1.547714	3.736848e-09
0.470012	1.547654	3.742092e-09
0.470671	1.547593	3.747343e-09
0.471332	1.547533	3.752602e-09
0.471993	1.547473	3.757867e-09
0.472656	1.547414	3.763140e-09
0.473319	1.547354	3.768421e-09
0.473984	1.547294	3.773709e-09
0.474649	1.547235	3.779004e-09
0.475315	1.547176	3.784307e-09
0.475982	1.547117	3.789617e-09
0.47665	1.547058	3.794935e-09
0.477319	1.547	3.800260e-09
0.477989	1.546942	3.805593e-09
0.47866	1.546883	3.810933e-09
0.479332	1.546825	3.816281e-09
0.48	1.546768	3.821600e-09
0.480005	1.546768	3.821636e-09
0.480678	1.54671	3.827002e-09
0.481353	1.546652	3.832376e-09
0.482028	1.546595	3.837757e-09
0.482705	1.546538	3.843145e-09
0.483382	1.546481	3.848541e-09
0.484061	1.546424	3.853945e-09
0.48474	1.546368	3.859357e-09
0.485421	1.546311	3.864776e-09
0.486102	1.546255	3.870202e-09
0.486784	1.546199	3.875636e-09
0.487467	1.546143	3.881078e-09
0.488152	1.546087	3.886528e-09
0.488837	1.546031	3.891985e-09
0.489523	1.545976	3.897450e-09
0.49021	1.545921	3.902922e-09
0.490898	1.545866	3.908402e-09
0.491587	1.545811	3.913890e-09
0.492277	1.545756	3.919385e-09
0.492968	1.545701	3.924889e-09
0.49366	1.545647	3.930400e-09
0.494353	1.545592	3.935918e-09
0.495046	1.545538	3.941445e-09
0.495741	1.545484	3.946979e-09
0.496437	1.545431	3.952521e-09
0.497134	1.545377	3.958071e-09
0.497832	1.545323	3.963628e-09
0.49853	1.54527	3.969193e-09
0.49923	1.545217	3.974766e-09
0.499931	1.545164	3.980347e-09
0.5	1.545159	3.980900e-09
0.500632	1.545111	3.985934e-09
0.501335	1.545058	3.991529e-09
0.502039	1.545006	3.997131e-09
0.502743	1.544953	4.002741e-09
0.503449	1.544901	4.008360e-09
0.504155	1.544849	4.013986e-09
0.504863	1.544797	4.019619e-09
0.505572	1.544745	4.025261e-09
0.506281	1.544694	4.030911e-09
0.506992	1.544642	4.036569e-09
0.507703	1.544591	4.042234e-09
0.508416	1.54454	4.047908e-09
0.50913	1.544489	4.053589e-09
0.509844	1.544438	4.059279e-09
0.51056	1.544387	4.064976e-09
0.511276	1.544336	4.070682e-09
0.511994	1.544286	4.076395e-09
0.512712	1.544236	4.082117e-09
0.513432	1.544186	4.087846e-09
0.514153	1.544136	4.093584e-09
0.514874	1.544086	4.099329e-09
0.515597	1.544036	4.105083e-09
0.516321	1.543986	4.110845e-09
0.517045	1.543937	4.116614e-09
0.517771	1.543888	4.122392e-09
0.518498	1.543838	4.128178e-09
0.519225	1.543789	4.133973e-09
0.519954	1.543741	4.139775e-09
0.520684	1.543692	4.145585e-09
0.521415	1.543643	4.151404e-09
0.522147	1.543595	4.157231e-09
0.522879	1.543547	4.163066e-09
0.523613	1.543498	4.168909e-09
0.524348	1.54345	4.174760e-09
0.525084	1.543402	4.180620e-09
0.525821	1.543355	4.186487e-09
0.526559	1.543307	4.192363e-09
0.527298	1.543259	4.198248e-09
0.528038	1.543212	4.204140e-09
0.528779	1.543165	4.210041e-09
0.529521	1.543118	4.215950e-09
0.530265	1.543071	4.221867e-09
0.531009	1.543024	4.227793e-09
0.531754	1.542977	4.233727e-09
0.532501	1.542931	4.239669e-09
0.533248	1.542884	4.245620e-09
0.533996	1.542838	4.251579e-09
0.534746	1.542792	4.257546e-09
0.535496	1.542746	4.263522e-09
0.536248	1.5427	4.269506e-09
0.537001	1.542654	4.275499e-09
0.537754	1.542608	4.281500e-09
0.538509	1.542563	4.287509e-09
0.539265	1.542517	4.293527e-09
0.540022	1.542472	4.299553e-09
0.54078	1.542427	4.305588e-09
0.541539	1.542382	4.311631e-09
0.542299	1.542337	4.317682e-09
0.54306	1.542292	4.323743e-09
0.543822	1.542247	4.329811e-09
0.544585	1.542203	4.335888e-09
0.54535	1.542158	4.341974e-09
0.546115	1.542114	4.348068e-09
0.546882	1.54207	4.354171e-09
0.547649	1.542026	4.360282e-09
0.548418	1.541982	4.366402e-09
0.549187	1.541938	4.372531e-09
0.549958	1.541894	4.378668e-09
0.55	1.541892	4.379000e-09
0.55073	1.541851	4.384812e-09
0.551503	1.541807	4.390965e-09
0.552277	1.541764	4.397126e-09
0.553052	1.541721	4.403297e-09
0.553829	1.541678	4.409475e-09
0.554606	1.541635	4.415663e-09
0.555384	1.541592	4.421859e-09
0.556164	1.541549	4.428064e-09
0.556944	1.541506	4.434277e-09
0.557726	1.541464	4.440499e-09
0.558509	1.541421	4.446730e-09
0.559293	1.541379	4.452970e-09
0.560078	1.541337	4.459219e-09
0.560864	1.541295	4.465476e-09
0.561651	1.541253	4.471742e-09
0.562439	1.541211	4.478017e-09
0.563229	1.541169	4.484300e-09
0.564019	1.541127	4.490593e-09
0.564811	1.541086	4.496894e-09
0.565604	1.541044	4.503204e-09
0.566397	1.541003	4.509523e-09
0.567192	1.540962	4.515851e-09
0.567988	1.540921	4.522188e-09
0.568786	1.54088	4.528533e-09
0.569584	1.540839	4.534888e-09
0.570383	1.540798	4.541251e-09
0.571184	1.540758	4.547624e-09
0.571986	1.540717	4.554005e-09
0.572788	1.540677	4.560395e-09
0.573592	1.540636	4.566795e-09
0.574397	1.540596	4.573203e-09
0.575204	1.540556	4.579620e-09
0.576011	1.540516	4.586046e-09
0.576819	1.540476	4.592481e-09
0.577629	1.540436	4.598926e-09
0.57844	1.540396	4.605379e-09
0.579251	1.540357	4.611841e-09
0.580064	1.540317	4.618313e-09
0.580879	1.540278	4.624793e-09
0.581694	1.540238	4.631283e-09
0.58251	1.540199	4.637782e-09
0.583328	1.54016	4.644290e-09
0.584147	1.540121	4.650807e-09
0.584966	1.540082	4.657333e-09
0.585787	1.540043	4.663868e-09
0.58661	1.540005	4.670413e-09
0.587433	1.539966	4.676966e-09
0.588257	1.539928	4.683529e-09
0.589083	1.539889	4.690101e-09
0.58991	1.539851	4.696682e-09
0.590738	1.539813	4.703273e-09
0.591567	1.539775	4.709873e-09
0.592397	1.539737	4.716482e-09
0.593229	1.539699	4.723100e-09
0.594061	1.539661	4.729728e-09
0.594895	1.539623	4.736365e-09
0.59573	1.539586	4.743011e-09
0.596566	1.539548	4.749666e-09
0.597403	1.539511	4.756331e-09
0.598242	1.539473	4.763006e-09
0.599082	1.539436	4.769689e-09
0.599922	1.539399	4.776382e-09
0.6	1.539396	4.777000e-09
0.600764	1.539362	4.783086e-09
0.601608	1.539325	4.789800e-09
0.602452	1.539288	4.796523e-09
0.603298	1.539251	4.803255e-09
0.604144	1.539215	4.809997e-09
0.604992	1.539178	4.816748e-09
0.605841	1.539142	4.823509e-09
0.606692	1.539105	4.830279e-09
0.607543	1.539069	4.837059e-09
0.608396	1.539033	4.843848e-09
0.60925	1.538997	4.850647e-09
0.610105	1.538961	4.857455e-09
0.610961	1.538925	4.864273e-09
0.611819	1.538889	4.871100e-09
0.612677	1.538853	4.877937e-09
0.613537	1.538817	4.884784e-09
0.614398	1.538782	4.891640e-09
0.615261	1.538746	4.898506e-09
0.616124	1.538711	4.905381e-09
0.616989	1.538676	4.912266e-09
0.617855	1.53864	4.919161e-09
0.618722	1.538605	4.926066e-09
0.619591	1.53857	4.932980e-09
0.62046	1.538535	4.939904e-09
0.621331	1.5385	4.946837e-09
0.622203	1.538465	4.953781e-09
0.623076	1.538431	4.960734e-09
0.623951	1.538396	4.967697e-09
0.624827	1.538362	4.974669e-09
0.625704	1.538327	4.981652e-09
0.626582	1.538293	4.988644e-09
0.627461	1.538259	4.995646e-09
0.628342	1.538224	5.002658e-09
0.629224	1.53819	5.009679e-09
0.630107	1.538156	5.016711e-09
0.630991	1.538122	5.023752e-09
0.631877	1.538088	5.030803e-09
0.632764	1.538055	5.037865e-09
0.633652	1.538021	5.044936e-09
0.634541	1.537987	5.052017e-09
0.635432	1.537954	5.059108e-09
0.636324	1.53792	5.066208e-09
0.637217	1.537887	5.073319e-09
0.638111	1.537854	5.080440e-09
0.639007	1.537821	5.087571e-09
0.639904	1.537787	5.094712e-09
0.640802	1.537754	5.101863e-09
0.641701	1.537722	5.109024e-09
0.642602	1.537689	5.116194e-09
0.643504	1.537656	5.123375e-09
0.644407	1.537623	5.130567e-09
0.645311	1.537591	5.137768e-09
0.646217	1.537558	5.144979e-09
0.647124	1.537526	5.152200e-09
0.648032	1.537493	5.159432e-09
0.648942	1.537461	5.166674e-09
0.649852	1.537429	5.173926e-09
0.65	1.537423	5.175100e-09
0.650765	1.537396	5.095964e-09
0.651678	1.537364	5.001429e-09
0.652593	1.537332	4.906761e-09
0.653509	1.537301	4.811960e-09
0.654426	1.537269	4.717026e-09
0.655344	1.537237	4.621959e-09
0.656264	1.537205	4.526758e-09
0.657185	1.537174	4.431424e-09
0.658108	1.537142	4.335956e-09
0.659031	1.537111	4.240354e-09
0.659956	1.537079	4.144617e-09
0.660882	1.537048	4.048747e-09
0.66181	1.537017	3.952742e-09
0.662739	1.536986	3.856602e-09
0.663669	1.536955	3.760327e-09
0.664601	1.536924	3.663917e-09
0.665533	1.536893	3.567372e-09
0.666467	1.536862	3.470691e-09
0.667403	1.536831	3.373874e-09
0.66834	1.5368	3.276922e-09
0.669278	1.53677	3.179834e-09
0.670217	1.536739	3.082609e-09
0.671158	1.536709	2.985248e-09
0.6721	1.536678	2.887750e-09
0.673043	1.536648	2.790115e-09
0.673988	1.536618	2.692343e-09
0.674933	1.536588	2.594435e-09
0.675881	1.536558	2.496388e-09
0.676829	1.536528	2.398204e-09
0.677779	1.536498	2.299883e-09
0.678731	1.536468	2.201423e-09
0.679683	1.536438	2.102825e-09
0.680637	1.536408	2.004089e-09
0.681592	1.536379	1.905214e-09
0.682549	1.536349	1.806200e-09
0.683507	1.536319	1.707047e-09
0.684466	1.53629	1.607755e-09
0.685427	1.536261	1.508324e-09
0.686389	1.536231	1.408754e-09
0.687352	1.536202	1.309043e-09
0.688317	1.536173	1.209193e-09
0.689283	1.536144	1.109202e-09
0.690251	1.536115	1.009071e-09
0.691219	1.536086	9.087998e-10
0.69219	1.536057	8.083876e-10
0.693161	1.536028	7.078345e-10
0.694134	1.535999	6.071402e-10
0.695108	1.535971	5.063047e-10
0.696084	1.535942	4.053276e-10
0.697061	1.535914	3.042088e-10
0.698039	1.535885	2.029480e-10
0.699019	1.535857	1.015452e-10
0.7	1.535828	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: —

BAK2 (HIKARI): all datasets

BaK (Barium crown)

BAK2 n,k 0.4–0.7 µm default

About BAK2 (HIKARI)

Hikari Glass Co., Ltd. is a Japanese company specializing in the manufacturing of high-quality optical glass and optical components, and is a subsidiary of Nikon Corporation. Known for its precision engineering and strict quality control, Hikari serves various industries including consumer electronics, scientific research, and industrial optics. The company offers a wide range of specialized optical materials, including various types of crown and flint glasses, which are used in applications demanding high levels of optical clarity and performance. Hikari's products often find use in lenses, prisms, and other optical elements where precision and reliability are critical. With the backing of Nikon's renowned expertise in optics and imaging, Hikari has become a respected name in the field of optics, serving both domestic and international markets. Their expertise in crafting custom solutions for complex optical requirements has made them a preferred choice for organizations in need of specialized glass materials. As a testament to their commitment to quality, Hikari Glass Co., Ltd. is often sought after for projects requiring the highest levels of optical performance and integrity.

More about BAK2 (HIKARI) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/specs/hikari/optical/BAK2.yml
ID: ds_99136e58feda
API: /v1/datasets/ds_99136e58feda

Plot