Optical constants

Refractive index of N-BAK4 (SCHOTT)

N-BAK4: n,k 0.334–2.5 µm

Data
formula 2 + tabulated k
Range
0.334–2.5 µm
Temperature
293 K
Licence
CC0-1.0

Plot

Click the plot to set the calculator wavelength.

At one wavelength

Range 0.334–2.5 µm
Refractive index n
1.56883
Extinction coefficient k
7.87323e-09
Permittivity ε1
2.46121
Permittivity ε2
2.47035e-08
Absorption coefficient α
0.00168376 cm⁻¹
Penetration depth δ = λ/(2πk)
1.18782e+10 nm
Abbe number Vd
55.976
Chromatic dispersion dn/dλ
-0.0523659 µm⁻¹
Group index ng
1.5996
Group velocity dispersion
92.9662 fs²/mm
Dispersion parameter D
-507.18 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

# N-BAK4 (SCHOTT): N-BAK4
schott_n_bak4 = ls.fetch_refractiveindex("specs", "SCHOTT-optical", "N-BAK4", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(schott_n_bak4.range_nm)  # (334, 2500) nm
eps = schott_n_bak4.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

Sellmeier (C in µm²) (formula 2), λ in µm
n2−1=1.28834642λ2λ2−0.00779980626+0.132817724λ2λ2−0.0315631177+0.945395373λ2λ2−105.965875

Valid from 0.334 to 2.5 µm.

Coefficients as stored
CiValue
C10.0
C21.28834642
C30.00779980626
C40.132817724
C50.0315631177
C60.945395373
C7105.965875

Comments and conditions

Conditions

temperature
293 K

Properties

thermal dispersion
type: formula A, coefficients: 3.06e-06 1.44e-08 -2.23e-11 5.46e-07 6.05e-10 0.189
nd
1.56883
Vd
55.98
glass code
569560.305
glass status
standard
density
value: 3046
thermal expansion
value: 6.99e-06, temperature range: 243 343; value: 7.93e-06, temperature range: 293 573
dPgF
-0.001
resistance
acid: 1.2; stain: 0.0; alkali: 1.0; climatic: 1.0; phosphate: 1.0

Thermo-optic coefficient

  • Schott thermal-dispersion model (reference temperature 293.0 K): dn/dT = 2.11e-06 K⁻¹ at 633 nm, dn/dT = 1.54e-06 K⁻¹ at 1310 nm, dn/dT = 1.49e-06 K⁻¹ at 1550 nm

References

Cite

SCHOTT Zemax catalog 2017-01-20b (obtained from http://www.schott.com); See also SCHOTT 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 420 wavelengths, the same grid as the API and the library
N-BAK4 (SCHOTT), N-BAK4: n and k versus wavelength
λ (µm)nk
0.3341.6029432.827200e-06
0.3356891.6023862.599029e-06
0.3373871.6018362.369705e-06
0.3390931.6012942.139220e-06
0.3408081.6007591.907570e-06
0.3425321.6002321.674748e-06
0.3442641.5997111.440749e-06
0.3460061.5991981.205566e-06
0.3477561.5986919.691941e-07
0.3495141.5981917.316263e-07
0.351.5980556.660400e-07
0.3512821.5976986.264242e-07
0.3530591.5972115.715292e-07
0.3548441.596735.163566e-07
0.3566391.5962564.609049e-07
0.3584431.5957884.051728e-07
0.3602561.5953263.491587e-07
0.3620781.5948692.928614e-07
0.3639091.5944192.362794e-07
0.3651.5941542.025700e-07
0.365751.5939741.927782e-07
0.3675991.5935351.686121e-07
0.3694591.5931021.443238e-07
0.371.5929771.372500e-07
0.3713271.5926741.289679e-07
0.3732051.5922511.172477e-07
0.3750931.5918341.054682e-07
0.376991.5914229.362910e-08
0.3788961.5910158.173013e-08
0.381.5907837.484300e-08
0.3808131.5906137.214595e-08
0.3827391.5902166.575450e-08
0.3846741.5898245.933072e-08
0.386621.5894375.287445e-08
0.3885751.5890554.638553e-08
0.391.588784.165800e-08
0.3905411.5886774.079644e-08
0.3925161.5883043.764895e-08
0.3945011.5879353.448554e-08
0.3964961.5875713.130613e-08
0.3985021.5872112.811064e-08
0.41.5869462.572300e-08
0.4005171.5868562.534872e-08
0.4025431.5865042.388254e-08
0.4045791.5861572.240895e-08
0.4051.5860862.210400e-08
0.4066251.5858142.160462e-08
0.4086811.5854752.097257e-08
0.4107481.5851412.033733e-08
0.4128261.584811.969887e-08
0.4149141.5844831.905718e-08
0.4170121.584161.841225e-08
0.4191211.583841.776406e-08
0.421.5837091.749400e-08
0.4212411.5835251.743668e-08
0.4233721.5832131.733828e-08
0.4255131.5829041.723938e-08
0.4276651.5825991.713998e-08
0.4298281.5822981.704008e-08
0.4320021.5821.693967e-08
0.4341871.5817061.683875e-08
0.4361.5814651.675500e-08
0.4363831.5814151.674609e-08
0.438591.5811271.669468e-08
0.4408081.5808431.664302e-08
0.4430371.5805611.659109e-08
0.4452781.5802831.653890e-08
0.447531.5800091.648645e-08
0.4497941.5797371.643373e-08
0.4520681.5794681.638074e-08
0.4543551.5792021.632749e-08
0.4566531.5789391.627396e-08
0.4589621.578681.622017e-08
0.461.5785641.619600e-08
0.4612841.5784231.598364e-08
0.4636171.5781681.559765e-08
0.4659611.5779171.520971e-08
0.4683181.5776691.481980e-08
0.4706871.5774231.442793e-08
0.4730671.577181.403407e-08
0.475461.5769391.363822e-08
0.4778641.5767011.324037e-08
0.4802811.5764661.284051e-08
0.482711.5762331.243862e-08
0.4851521.5760031.203471e-08
0.4876051.5757751.162875e-08
0.4900721.575551.122073e-08
0.492551.5753271.081065e-08
0.4950411.5751061.039850e-08
0.4975451.5748889.984266e-09
0.51.5746789.578100e-09
0.5000611.5746729.574611e-09
0.5025911.5744599.430984e-09
0.5051321.5742489.286631e-09
0.5076871.5740399.141548e-09
0.5102551.5738328.995731e-09
0.5128361.5736278.849177e-09
0.5154291.5734248.701881e-09
0.5180361.5732248.553841e-09
0.5206561.5730258.405051e-09
0.5232891.5728298.255510e-09
0.5259361.5726358.105212e-09
0.5285961.5724437.954153e-09
0.531271.5722527.802331e-09
0.5339561.5720647.649741e-09
0.5366571.5718777.496379e-09
0.5393711.5716937.342241e-09
0.5420991.571517.187324e-09
0.5448411.5713297.031624e-09
0.5461.5712546.965800e-09
0.5475971.571156.986170e-09
0.5503661.5709737.021506e-09
0.553151.5707977.057020e-09
0.5559471.5706247.092715e-09
0.5587591.5704527.128590e-09
0.5615851.5702817.164646e-09
0.5644251.5701137.200885e-09
0.567281.5699467.237307e-09
0.5701491.5697817.273913e-09
0.5730331.5696177.310704e-09
0.5759311.5694557.347681e-09
0.5788441.5692947.384846e-09
0.581.5692317.399600e-09
0.5817711.5691357.509980e-09
0.5847141.5689787.693349e-09
0.5876711.5688227.877646e-09
0.5906431.5686678.062874e-09
0.593631.5685148.249039e-09
0.5966331.5683638.436146e-09
0.599651.5682138.624200e-09
0.6026831.5680648.813204e-09
0.6057311.5679179.003164e-09
0.6087951.5677719.194085e-09
0.6118741.5676269.385972e-09
0.6149681.5674839.578829e-09
0.6180791.5673419.772661e-09
0.621.5672549.892400e-09
0.6212051.56729.911632e-09
0.6243461.5670619.961791e-09
0.6275041.5669231.001220e-08
0.6306781.5667861.006287e-08
0.6338681.5666511.011380e-08
0.6370731.5665161.016498e-08
0.6402961.5663831.021642e-08
0.6435341.5662511.026812e-08
0.6467891.566121.032008e-08
0.650061.5659911.037231e-08
0.6533481.5658621.042479e-08
0.6566521.5657351.047755e-08
0.6599731.5656091.053057e-08
0.661.5656081.053100e-08
0.6633111.5654831.021344e-08
0.6666661.5653599.891686e-09
0.6700381.5652369.568302e-09
0.6734261.5651149.243282e-09
0.6768321.5649938.916619e-09
0.6802551.5648738.588304e-09
0.6836961.5647548.258328e-09
0.6871541.5646367.926683e-09
0.6906291.5645197.593361e-09
0.6941221.5644037.258353e-09
0.6976331.5642886.921651e-09
0.71.5642116.694600e-09
0.7011611.5641746.727555e-09
0.7047071.564066.828212e-09
0.7082711.5639486.929379e-09
0.7118541.5638367.031056e-09
0.7154541.5637267.133249e-09
0.7190721.5636167.235958e-09
0.7227091.5635077.339186e-09
0.7263641.5633997.442936e-09
0.7300381.5632927.547212e-09
0.733731.5631857.652014e-09
0.7374411.563087.757347e-09
0.7411711.5629757.863212e-09
0.7449191.5628717.969613e-09
0.7486871.5627678.076552e-09
0.7524741.5626658.184032e-09
0.7562791.5625638.292056e-09
0.7601041.5624628.400625e-09
0.7639491.5623628.509744e-09
0.7678121.5622628.619415e-09
0.7716961.5621638.729640e-09
0.7755991.5620658.840423e-09
0.7795211.5619678.951766e-09
0.7834641.561879.063673e-09
0.7874261.5617749.176145e-09
0.7914091.5616789.289186e-09
0.7954111.5615839.402799e-09
0.7994341.5614889.516987e-09
0.8034781.5613949.631752e-09
0.8075411.5613019.747097e-09
0.8116251.5612099.863026e-09
0.815731.5611169.979541e-09
0.8198561.5610251.009665e-08
0.8240031.5609341.021434e-08
0.828171.5608431.033263e-08
0.8323591.5607531.045152e-08
0.8365681.5606641.057102e-08
0.8407991.5605751.069111e-08
0.8450521.5604871.081182e-08
0.8493261.5603991.093313e-08
0.8536211.5603111.105506e-08
0.8579391.5602241.117760e-08
0.8622781.5601381.130076e-08
0.8666391.5600521.142455e-08
0.8710221.5599661.154896e-08
0.8754271.5598811.167401e-08
0.8798551.5597961.179968e-08
0.8843051.5597121.192599e-08
0.8887771.5596281.205294e-08
0.8932721.5595451.218053e-08
0.897791.5594611.230877e-08
0.9023311.5593791.243765e-08
0.9068951.5592961.256719e-08
0.9114811.5592141.269738e-08
0.9160911.5591321.282823e-08
0.9207241.5590511.295974e-08
0.9253811.558971.309192e-08
0.9300611.5588891.322476e-08
0.9347651.5588091.335828e-08
0.9394931.5587291.349247e-08
0.9442451.5586491.362735e-08
0.949021.5585691.376290e-08
0.953821.558491.389914e-08
0.9586441.5584111.403607e-08
0.9634921.5583321.417369e-08
0.9683651.5582541.431200e-08
0.9732631.5581761.445102e-08
0.9781851.5580981.459074e-08
0.9831331.558021.473117e-08
0.9881051.5579421.487230e-08
0.9931031.5578651.501415e-08
0.9981251.5577881.515672e-08
1.003171.5577111.530001e-08
1.008251.5576341.544402e-08
1.013351.5575581.558876e-08
1.018471.5574811.573424e-08
1.023621.5574051.588045e-08
1.02881.5573291.602740e-08
1.0341.5572531.617509e-08
1.039231.5571771.632353e-08
1.044491.5571011.647272e-08
1.049771.5570261.662266e-08
1.055081.556951.677337e-08
1.061.5568811.691300e-08
1.060421.5568751.697645e-08
1.065781.5567991.779288e-08
1.071171.5567241.861345e-08
1.076591.5566491.943817e-08
1.082031.5565742.026705e-08
1.087511.5564992.110013e-08
1.093011.5564242.193743e-08
1.098531.5563492.277895e-08
1.104091.5562742.362474e-08
1.109671.5561992.447480e-08
1.115291.5561242.532916e-08
1.120931.5560492.618784e-08
1.12661.5559752.705087e-08
1.132291.55592.791825e-08
1.138021.5558252.879003e-08
1.143781.555752.966622e-08
1.149561.5556753.054683e-08
1.155371.55563.143190e-08
1.161221.5555253.232145e-08
1.167091.555453.321550e-08
1.172991.5553753.411406e-08
1.178931.55533.501718e-08
1.184891.5552243.592486e-08
1.190881.5551493.683713e-08
1.19691.5550733.775401e-08
1.202961.5549983.867553e-08
1.209041.5549223.960172e-08
1.215161.5548464.053258e-08
1.22131.554774.146816e-08
1.227481.5546944.240846e-08
1.233691.5546184.335353e-08
1.239931.5545414.430337e-08
1.24621.5544654.525802e-08
1.25251.5543884.621749e-08
1.258841.5543114.718182e-08
1.26521.5542344.815102e-08
1.27161.5541574.912513e-08
1.278031.5540795.010416e-08
1.28451.5540025.108814e-08
1.290991.5539245.207710e-08
1.297521.5538455.307107e-08
1.304091.5537675.407006e-08
1.310681.5536885.507410e-08
1.317311.5536095.608322e-08
1.323971.553535.709744e-08
1.330671.5534515.811680e-08
1.33741.5533715.914131e-08
1.344161.5532916.017100e-08
1.350961.553216.120589e-08
1.357791.553136.224603e-08
1.364661.5530496.329142e-08
1.371561.5529676.434210e-08
1.37851.5528866.539810e-08
1.385471.5528046.645943e-08
1.392481.5527216.752613e-08
1.399521.5526396.859823e-08
1.40661.5525566.967575e-08
1.413711.5524727.075872e-08
1.420861.5523887.184717e-08
1.428051.5523047.294112e-08
1.435271.5522197.404061e-08
1.442531.5521347.514565e-08
1.449831.5520487.625629e-08
1.457161.5519627.737254e-08
1.464531.5518767.849444e-08
1.471941.5517897.962201e-08
1.479381.5517028.075528e-08
1.486861.5516148.189429e-08
1.494381.5515258.303905e-08
1.501941.5514378.418961e-08
1.509541.5513478.534599e-08
1.517171.5512578.650821e-08
1.524851.5511678.767631e-08
1.531.5511068.846100e-08
1.532561.5510769.178697e-08
1.540311.5509841.018673e-07
1.54811.5508921.119985e-07
1.555931.55081.221810e-07
1.56381.5507061.324150e-07
1.571711.5506121.427008e-07
1.579661.5505181.530386e-07
1.587651.5504231.634286e-07
1.595681.5503271.738713e-07
1.603751.5502311.843667e-07
1.611861.5501341.949152e-07
1.620011.5500362.055171e-07
1.62821.5499382.161726e-07
1.636441.5498392.268819e-07
1.644711.5497392.376455e-07
1.653031.5496392.484635e-07
1.661391.5495382.593362e-07
1.669791.5494362.702638e-07
1.678241.5493332.812468e-07
1.686731.549232.922853e-07
1.695261.5491263.033796e-07
1.703831.5490213.145301e-07
1.712451.5489153.257369e-07
1.721111.5488093.370004e-07
1.729821.5487013.483209e-07
1.738561.5485933.596986e-07
1.747361.5484843.711339e-07
1.756191.5483743.826270e-07
1.765081.5482633.941782e-07
1.7741.5481524.057879e-07
1.782981.5480394.174563e-07
1.791991.5479264.291837e-07
1.801061.5478114.409704e-07
1.810171.5476964.528167e-07
1.819321.547584.647229e-07
1.828521.5474634.766894e-07
1.837771.5473454.887164e-07
1.847071.5472255.008042e-07
1.856411.5471055.129531e-07
1.86581.5469845.251635e-07
1.875231.5468625.374356e-07
1.884721.5467385.497698e-07
1.894251.5466145.621664e-07
1.903831.5464895.746257e-07
1.913461.5463625.871480e-07
1.923141.5462345.997336e-07
1.932861.5461056.123829e-07
1.942641.5459756.250962e-07
1.952461.5458446.378737e-07
1.962341.5457126.507159e-07
1.971.5456096.606800e-07
1.972261.5455796.726263e-07
1.982241.5454447.252834e-07
1.992261.5453087.782068e-07
2.002341.5451718.313979e-07
2.012471.5450328.848580e-07
2.022641.5448929.385885e-07
2.032871.5447519.925908e-07
2.043161.5446091.046866e-06
2.053491.5444651.101416e-06
2.063881.544321.156242e-06
2.074311.5441741.211345e-06
2.08481.5440261.266727e-06
2.095351.5438771.322388e-06
2.105951.5437261.378332e-06
2.11661.5435741.434558e-06
2.12731.543421.491069e-06
2.138061.5432651.547865e-06
2.148881.5431081.604949e-06
2.159741.542951.662321e-06
2.170671.5427911.719984e-06
2.181641.5426291.777938e-06
2.192681.5424661.836186e-06
2.203771.5423021.894728e-06
2.214911.5421361.953566e-06
2.226121.5419682.012701e-06
2.237381.5417982.072136e-06
2.248691.5416272.131871e-06
2.260061.5414542.191909e-06
2.271491.541282.252250e-06
2.282981.5411032.312896e-06
2.294531.5409252.373849e-06
2.306131.5407452.435110e-06
2.31781.5405632.496681e-06
2.3251.540452.534700e-06
2.329521.5403792.595891e-06
2.34131.5401932.755369e-06
2.353141.5400062.915655e-06
2.365051.5398163.076751e-06
2.377011.5396243.238662e-06
2.389031.5394313.401392e-06
2.401111.5392353.564945e-06
2.413261.5390373.729325e-06
2.425461.5388383.894536e-06
2.437731.5386364.060583e-06
2.450061.5384314.227470e-06
2.462451.5382254.395200e-06
2.47491.5380174.563780e-06
2.487421.5378064.733211e-06
2.51.5375934.903500e-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
—