Optical constants

Refractive index of J-BK7 (HIKARI)

J-BK7: n,k 0.365–2.058 µm

Data
formula 3 + tabulated k
Range
0.365–2.058 µm
Temperature
296 K
Licence
CC0-1.0

Plot

Click the plot to set the calculator wavelength.

At one wavelength

Range 0.365–2.058 µm
Refractive index n
1.5168
Extinction coefficient k
1.87414e-08
Permittivity ε1
2.30068
Permittivity ε2
5.68540e-08
Absorption coefficient α
0.00400803 cm⁻¹
Penetration depth δ = λ/(2πk)
4.98998e+09 nm
Abbe number Vd
63.881
Chromatic dispersion dn/dλ
-0.0419549 µm⁻¹
Group index ng
1.54145
Group velocity dispersion
71.0245 fs²/mm
Dispersion parameter D
-387.477 ps/(nm·km)
Photon energy
2.11001 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

# J-BK7 (HIKARI): J-BK7
hikari_j_bk7 = ls.fetch_refractiveindex("specs", "HIKARI-optical", "J-BK7", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(hikari_j_bk7.range_nm)  # (365.015, 2058.09) nm
eps = hikari_j_bk7.eps([633])  # complex permittivity

Downloads the original record once (pinned to the imported snapshot) and caches it.

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
n2=2.27109726−0.00947304881⁢λ2.0−8.9187152×10-5⁢λ4.0+0.0109352525⁢λ−2.0+0.000136527555⁢λ−4.0+1.68617824×10-6⁢λ−6.0+5.85391298×10-8⁢λ−8.0

Valid from 0.365015 to 2.05809 µm.

Coefficients as stored
CiValue
C12.27109726
C2-0.00947304881
C32.0
C4-8.9187152e-05
C54.0
C60.0109352525
C7-2.0
C80.000136527555
C9-4.0
C101.68617824e-06
C11-6.0
C125.85391298e-08
C13-8.0

Comments and conditions

Conditions

temperature
296 K

Properties

thermal dispersion
type: formula A, coefficients: -7.9571e-09 1.4286e-08 -1.3882e-12 4.674e-07 4.1858e-10 0.17067
nd
1.516800
Vd
63.880667
glass status
preferred
density
value: 2520
thermal expansion
value: 7.1e-06, temperature range: 243 343
dPgF
-0.0012
resistance
phosphate: 1.0

Thermo-optic coefficient

  • Schott thermal-dispersion model (reference temperature 296.0 K): dn/dT = 5.34e-07 K⁻¹ at 633 nm, dn/dT = 1.13e-07 K⁻¹ at 1310 nm, dn/dT = 7.88e-08 K⁻¹ at 1550 nm

References

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 421 wavelengths, the same grid as the API and the library
J-BK7 (HIKARI), J-BK7: n and k versus wavelength
λ (µm)nk
0.3650151.5363913.504958e-08
0.3666011.5361063.331354e-08
0.3681931.5358233.156996e-08
0.3697931.5355442.981881e-08
0.371.5355082.959200e-08
0.3713991.5352672.970394e-08
0.3730131.5349932.983302e-08
0.3746331.5347222.996266e-08
0.3762611.5344543.009286e-08
0.3778951.5341883.022362e-08
0.3795371.5339253.035495e-08
0.381.5338513.039200e-08
0.3811861.5336642.863299e-08
0.3828421.5334062.617637e-08
0.3845051.533152.370909e-08
0.3861751.5328972.123108e-08
0.3878531.5326471.874231e-08
0.3895381.5323991.624272e-08
0.391.5323311.555700e-08
0.391231.5321531.521272e-08
0.392931.531911.473700e-08
0.3946371.5316691.425922e-08
0.3963511.5314311.377936e-08
0.3980731.5311941.329742e-08
0.3998021.530961.281338e-08
0.41.5309341.275800e-08
0.4015391.5307291.280709e-08
0.4032831.5304991.286274e-08
0.4050351.5302721.291863e-08
0.4067951.5300471.297476e-08
0.4085621.5298241.303113e-08
0.4103371.5296031.308775e-08
0.412121.5293851.314461e-08
0.413911.5291681.320173e-08
0.4157081.5289541.325909e-08
0.4175141.5287411.331670e-08
0.4193281.5285311.337456e-08
0.421.5284531.339600e-08
0.4211491.5283221.363479e-08
0.4229791.5281161.401488e-08
0.4248171.5279111.439663e-08
0.4266621.5277081.478003e-08
0.4285161.5275081.516510e-08
0.4303771.5273091.555184e-08
0.4322471.5271121.594026e-08
0.4341251.5269161.633037e-08
0.436011.5267231.672218e-08
0.4379051.5265311.711568e-08
0.4398071.5263421.751090e-08
0.441.5263221.755100e-08
0.4417181.5261541.761953e-08
0.4436371.5259671.769610e-08
0.4455641.5257821.777299e-08
0.4474991.52561.785023e-08
0.4494431.5254181.792779e-08
0.4513961.5252391.800570e-08
0.4533571.5250611.808394e-08
0.4553261.5248841.816252e-08
0.4573041.5247091.824145e-08
0.4592911.5245361.832071e-08
0.461.5244751.834900e-08
0.4612861.5243651.815354e-08
0.463291.5241951.784904e-08
0.4653031.5240261.754322e-08
0.4673241.5238591.723607e-08
0.4693541.5236931.692759e-08
0.4713931.5235291.661776e-08
0.4734411.5233671.630659e-08
0.4754981.5232051.599407e-08
0.4775641.5230461.568019e-08
0.4796381.5228871.536495e-08
0.481.522861.531000e-08
0.4817221.522731.536485e-08
0.4838151.5225751.543150e-08
0.4859171.5224211.549844e-08
0.4880271.5222681.556568e-08
0.4901481.5221161.563320e-08
0.4922771.5219661.570102e-08
0.4944151.5218171.576913e-08
0.4965631.521671.583754e-08
0.4987211.5215231.590625e-08
0.51.5214371.594700e-08
0.5008871.5213781.597530e-08
0.5030631.5212341.604471e-08
0.5052481.5210921.611443e-08
0.5074431.520951.618444e-08
0.5096481.520811.625477e-08
0.5118621.5206711.632539e-08
0.5140861.5205341.639633e-08
0.5163191.5203971.646757e-08
0.5185621.5202621.653912e-08
0.5208151.5201271.661099e-08
0.5230771.5199941.668316e-08
0.5253491.5198621.675565e-08
0.5276321.5197311.682845e-08
0.5299241.5196011.690157e-08
0.5322261.5194721.697501e-08
0.5345381.5193451.704877e-08
0.536861.5192181.712284e-08
0.5391931.5190921.719724e-08
0.5415351.5189681.727196e-08
0.5438871.5188441.734701e-08
0.546251.5187211.742238e-08
0.5486231.51861.749808e-08
0.551.518531.754200e-08
0.5510071.5184791.757411e-08
0.55341.5183591.765047e-08
0.5558041.5182411.772716e-08
0.5582191.5181231.780419e-08
0.5606441.5180061.788154e-08
0.563081.517891.795924e-08
0.5655261.5177751.803727e-08
0.5679821.5176611.811564e-08
0.570451.5175481.819435e-08
0.5729281.5174361.827341e-08
0.5754171.5173251.835280e-08
0.5779171.5172141.843255e-08
0.5804271.5171051.851263e-08
0.5829491.5169961.859307e-08
0.5854811.5168881.867386e-08
0.5880251.5167811.875499e-08
0.5905791.5166741.883648e-08
0.5931451.5165691.891832e-08
0.5957221.5164641.900052e-08
0.598311.516361.908308e-08
0.61.5162931.913700e-08
0.6009091.5162571.935499e-08
0.6035191.5161551.998109e-08
0.6061411.5160532.060991e-08
0.6087741.5159522.124146e-08
0.6114191.5158522.187575e-08
0.6140751.5157532.251280e-08
0.6167431.5156542.315262e-08
0.6194221.5155562.379522e-08
0.6221131.5154592.444061e-08
0.6248161.5153622.508880e-08
0.627531.5152662.573981e-08
0.6302561.5151712.639365e-08
0.6329941.5150772.705032e-08
0.6357441.5149832.770985e-08
0.6385061.514892.837225e-08
0.641281.5147972.903752e-08
0.6440661.5147052.970569e-08
0.6468641.5146143.037675e-08
0.6496741.5145243.105073e-08
0.651.5145133.112900e-08
0.6524961.5144343.152841e-08
0.6553311.5143443.198200e-08
0.6581781.5142563.243756e-08
0.6610371.5141673.289511e-08
0.6639081.514083.335463e-08
0.6667931.5139933.381616e-08
0.6696891.5139063.427969e-08
0.6725991.513823.474523e-08
0.6755211.5137353.521280e-08
0.6784551.513653.568240e-08
0.6814031.5135663.615404e-08
0.6843631.5134833.662772e-08
0.6873361.5133993.710347e-08
0.6903221.5133173.758128e-08
0.6933211.5132353.806117e-08
0.6963331.5131533.854314e-08
0.6993581.5130723.902720e-08
0.71.5130553.913000e-08
0.7023961.5129913.987954e-08
0.7054471.5129114.083420e-08
0.7085121.5128324.179299e-08
0.711591.5127524.275596e-08
0.7146811.5126744.372311e-08
0.7177861.5125954.469446e-08
0.7209041.5125184.567003e-08
0.7240361.512444.664983e-08
0.7271811.5123634.763390e-08
0.730341.5122874.862224e-08
0.7335131.5122114.961487e-08
0.73671.5121355.061181e-08
0.73991.512065.161309e-08
0.7431141.5119855.261871e-08
0.7463421.5119115.362871e-08
0.7495851.5118375.464309e-08
0.7528411.5117635.566188e-08
0.7561121.511695.668509e-08
0.7593961.5116175.771275e-08
0.7626951.5115455.874488e-08
0.7660091.5114735.978148e-08
0.7693361.5114016.082259e-08
0.7726791.511336.186823e-08
0.7760351.5112596.291840e-08
0.7794071.5111886.397314e-08
0.7827931.5111186.503246e-08
0.7861931.5110476.609638e-08
0.7896091.5109786.716493e-08
0.7930391.5109086.823812e-08
0.7964841.5108396.931596e-08
0.7999441.5107717.039849e-08
0.81.5107697.041600e-08
0.8034191.5107026.874408e-08
0.8069091.5106346.703743e-08
0.8104151.5105666.532335e-08
0.8139351.5104996.360184e-08
0.8174711.5104316.187284e-08
0.8210231.5103646.013633e-08
0.8245891.5102975.839228e-08
0.8281721.5102315.664065e-08
0.8317691.5101655.488141e-08
0.8353831.5100995.311453e-08
0.8390121.5100335.133997e-08
0.8426571.5099674.955771e-08
0.8463171.5099024.776770e-08
0.8499941.5098374.596992e-08
0.8536871.5097724.416432e-08
0.8573951.5097084.235088e-08
0.861121.5096434.052957e-08
0.8648611.5095793.870034e-08
0.8686181.5095153.686316e-08
0.8723911.5094523.501801e-08
0.8761811.5093883.316483e-08
0.8799881.5093253.130361e-08
0.8838111.5092612.943430e-08
0.887651.5091982.755687e-08
0.8915061.5091362.567129e-08
0.8953791.5090732.377751e-08
0.8992691.509012.187551e-08
0.91.5089992.151800e-08
0.9031751.5089482.184752e-08
0.9070991.5088862.225467e-08
0.911041.5088242.266360e-08
0.9149981.5087622.307429e-08
0.9189721.50872.348678e-08
0.9229651.5086392.390105e-08
0.9269741.5085772.431712e-08
0.9310011.5085162.473500e-08
0.9350461.5084552.515470e-08
0.9391081.5083932.557622e-08
0.9431881.5083322.599957e-08
0.9472851.5082722.642476e-08
0.95141.5082112.685180e-08
0.9555331.508152.728069e-08
0.9596841.5080892.771145e-08
0.9638531.5080292.814407e-08
0.9680411.5079682.857858e-08
0.9722461.5079082.901497e-08
0.976471.5078482.945326e-08
0.9807121.5077872.989346e-08
0.9849721.5077273.033556e-08
0.9892511.5076673.077959e-08
0.9935491.5076073.122554e-08
0.9978651.5075473.167344e-08
11.5075173.189500e-08
1.00221.5074873.185976e-08
1.006551.5074273.179001e-08
1.010931.5073673.171996e-08
1.015321.5073073.164961e-08
1.019731.5072473.157894e-08
1.024161.5071873.150798e-08
1.028611.5071283.143670e-08
1.033081.5070683.136512e-08
1.037561.5070083.129322e-08
1.042071.5069483.122101e-08
1.04661.5068883.114849e-08
1.051151.5068283.107565e-08
1.055711.5067683.100250e-08
1.06031.5067093.092902e-08
1.06491.5066493.085523e-08
1.069531.5065893.078112e-08
1.074181.5065293.070669e-08
1.078841.5064693.063193e-08
1.083531.5064093.055685e-08
1.088241.5063493.048144e-08
1.092961.5062883.040571e-08
1.097711.5062283.032964e-08
1.102481.5061683.025325e-08
1.107271.5061073.017652e-08
1.112081.5060473.009946e-08
1.116911.5059863.002206e-08
1.121761.5059262.994433e-08
1.126641.5058652.986626e-08
1.131531.5058042.978786e-08
1.136451.5057442.970911e-08
1.141381.5056832.963002e-08
1.146341.5056212.955058e-08
1.151321.505562.947080e-08
1.156321.5054992.939068e-08
1.161351.5054372.931020e-08
1.166391.5053762.922938e-08
1.171461.5053142.914821e-08
1.176551.5052522.906668e-08
1.181661.505192.898480e-08
1.186791.5051282.890256e-08
1.191951.5050662.881997e-08
1.197131.5050042.873701e-08
1.21.5049692.869100e-08
1.202331.5049413.137501e-08
1.207551.5048783.739576e-08
1.21281.5048154.344267e-08
1.218071.5047524.951584e-08
1.223361.5046895.561540e-08
1.228671.5046256.174146e-08
1.234011.5045626.789413e-08
1.239371.5044987.407353e-08
1.244751.5044348.027978e-08
1.250161.5043698.651298e-08
1.255591.5043059.277327e-08
1.261051.504249.906075e-08
1.266531.5041751.053755e-07
1.272031.504111.117178e-07
1.277551.5040441.180875e-07
1.28311.5039791.244850e-07
1.288681.5039131.309102e-07
1.294281.5038471.373634e-07
1.29991.503781.438446e-07
1.305551.5037141.503539e-07
1.311221.5036471.568916e-07
1.316911.503581.634576e-07
1.322641.5035121.700521e-07
1.328381.5034441.766753e-07
1.334151.5033761.833273e-07
1.339951.5033081.900082e-07
1.345771.5032391.967181e-07
1.351621.503172.034571e-07
1.357491.5031012.102254e-07
1.363381.5030312.170231e-07
1.369311.5029612.238504e-07
1.375261.5028912.307073e-07
1.381231.5028212.375940e-07
1.387231.502752.445106e-07
1.393261.5026782.514573e-07
1.399311.5026072.584341e-07
1.41.5025992.592300e-07
1.405391.5025352.567346e-07
1.411491.5024622.539072e-07
1.417631.502392.510675e-07
1.423781.5023172.482155e-07
1.429971.5022432.453512e-07
1.436181.5021692.424743e-07
1.442421.5020952.395850e-07
1.448691.502022.366831e-07
1.454981.5019452.337686e-07
1.46131.501872.308415e-07
1.467651.5017942.279016e-07
1.474031.5017182.249490e-07
1.480431.5016412.219835e-07
1.486861.5015642.190052e-07
1.493321.5014862.160139e-07
1.499811.5014082.130096e-07
1.506321.5013292.099922e-07
1.512871.501252.069618e-07
1.519441.5011712.039182e-07
1.526041.5010912.008614e-07
1.532671.501011.977913e-07
1.539331.5009291.947078e-07
1.546011.5008481.916110e-07
1.552731.5007661.885007e-07
1.559481.5006841.853769e-07
1.566251.5006011.822395e-07
1.573051.5005171.790885e-07
1.579891.5004331.759238e-07
1.586751.5003491.727454e-07
1.593641.5002631.695531e-07
1.61.5001851.666100e-07
1.600571.5001781.677973e-07
1.607521.5000911.823337e-07
1.61451.5000051.969333e-07
1.621521.4999172.115964e-07
1.628561.4998292.263231e-07
1.635641.4997412.411138e-07
1.642741.4996522.559687e-07
1.649881.4995622.708882e-07
1.657051.4994712.858725e-07
1.664251.499383.009219e-07
1.671481.4992893.160367e-07
1.678741.4991963.312171e-07
1.686031.4991043.464635e-07
1.693351.499013.617761e-07
1.700711.4989163.771552e-07
1.70811.4988213.926012e-07
1.715521.4987254.081142e-07
1.722971.4986294.236947e-07
1.730461.4985324.393428e-07
1.737971.4984344.550589e-07
1.745521.4983364.708433e-07
1.753111.4982374.866962e-07
1.760721.4981375.026180e-07
1.768371.4980365.186090e-07
1.776051.4979355.346695e-07
1.783771.4978335.507997e-07
1.791521.497735.670000e-07
1.79931.4976265.832707e-07
1.81.4976175.847300e-07
1.807121.4975226.105372e-07
1.814971.4974176.389982e-07
1.822851.4973116.675828e-07
1.830771.4972046.962916e-07
1.838731.4970967.251251e-07
1.846711.4969887.540839e-07
1.854741.4968787.831685e-07
1.862791.4967688.123794e-07
1.870891.4966578.417172e-07
1.879011.4965458.711825e-07
1.887181.4964329.007758e-07
1.895371.4963199.304976e-07
1.903611.4962049.603486e-07
1.911881.4960899.903292e-07
1.920181.4959721.020440e-06
1.928531.4958551.050682e-06
1.93691.4957361.081055e-06
1.945321.4956171.111560e-06
1.953771.4954971.142197e-06
1.962261.4953761.172968e-06
1.970781.4952541.203872e-06
1.979341.495131.234911e-06
1.987941.4950061.266084e-06
1.996581.4948811.297393e-06
21.4948311.309800e-06
2.005251.4947551.372273e-06
2.013961.4946271.475907e-06
2.022711.4944991.579990e-06
2.03151.494371.684527e-06
2.040321.4942391.789517e-06
2.049191.4941081.894963e-06
2.058091.4939752.000868e-06

Optical transmission calculator

Free-standing sample in vacuum, normal incidence
Method
Transmittance T
—
Reflectance R
—

Fresnel reflection calculator

Direction
Rp
—
Rs
—
R = (Rp+Rs)/2
—
Phase φp
—
Phase φs
—
Brewster angle θB
—
Critical angle θC
—