Optical constants

Refractive index of N-LAK21 (SCHOTT)

N-LAK21: n,k 0.32–2.5 µm

Data
formula 2 + tabulated k
Range
0.32–2.5 µm
Temperature
293 K
Licence
CC0-1.0

Plot

Click the plot to set the calculator wavelength.

At one wavelength

Range 0.32–2.5 µm
Refractive index n
1.64049
Extinction coefficient k
1.57801e-08
Permittivity ε1
2.69122
Permittivity ε2
5.17744e-08
Absorption coefficient α
0.00337473 cm⁻¹
Penetration depth δ = λ/(2πk)
5.92640e+09 nm
Abbe number Vd
60.102
Chromatic dispersion dn/dλ
-0.0551182 µm⁻¹
Group index ng
1.67288
Group velocity dispersion
95.4222 fs²/mm
Dispersion parameter D
-520.579 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-LAK21 (SCHOTT): N-LAK21
schott_n_lak21 = ls.fetch_refractiveindex("specs", "SCHOTT-optical", "N-LAK21", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(schott_n_lak21.range_nm)  # (320, 2500) nm
eps = schott_n_lak21.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=1.22718116λ2λ2−0.00602075682+0.420783743λ2λ2−0.0196862889+1.01284843λ2λ2−88.4370099

Valid from 0.32 to 2.5 µm.

Coefficients as stored
CiValue
C10.0
C21.22718116
C30.00602075682
C40.420783743
C50.0196862889
C61.01284843
C788.4370099

Comments and conditions

Conditions

temperature
293 K

Properties

thermal dispersion
type: formula A, coefficients: -2.36e-06 1.15e-08 1.11e-11 3.1e-07 2.78e-10 0.234
nd
1.64049
Vd
60.1
glass code
640601.374
glass status
standard
density
value: 3740
thermal expansion
value: 6.8e-06, temperature range: 243 343; value: 8.1e-06, temperature range: 293 573
dPgF
-0.0017
resistance
acid: 53.2; stain: 2.0; alkali: 4.3; climatic: 4.0; phosphate: 4.3

Thermo-optic coefficient

  • Schott thermal-dispersion model (reference temperature 293.0 K): dn/dT = -7.52e-07 K⁻¹ at 633 nm, dn/dT = -1.10e-06 K⁻¹ at 1310 nm, dn/dT = -1.12e-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 421 wavelengths, the same grid as the API and the library
N-LAK21 (SCHOTT), N-LAK21: n and k versus wavelength
λ (µm)nk
0.321.6803573.278700e-06
0.3216531.6797283.070723e-06
0.3233141.6791072.861671e-06
0.3249851.6784942.651540e-06
0.3266631.6778892.440323e-06
0.3283511.6772922.228015e-06
0.3300471.6767032.014610e-06
0.3317521.6761211.800103e-06
0.3334651.6755471.584488e-06
0.3341.675371.517200e-06
0.3351881.674981.451063e-06
0.3369191.674421.354650e-06
0.3386591.6738681.257740e-06
0.3404091.6733221.160329e-06
0.3421671.6727841.062415e-06
0.3439351.6722529.639947e-07
0.3457111.6717278.650663e-07
0.3474971.6712097.656270e-07
0.3492921.6706976.656740e-07
0.351.6704986.262500e-07
0.3510961.6701916.015780e-07
0.352911.6696925.607627e-07
0.3547331.6691995.197365e-07
0.3565651.6687124.784985e-07
0.3584071.6682324.370474e-07
0.3602581.6677573.953822e-07
0.3621191.6672883.535018e-07
0.363991.6668243.114051e-07
0.3651.6665772.886700e-07
0.365871.6663672.766260e-07
0.367761.6659142.504623e-07
0.369661.6654682.241634e-07
0.371.6653892.194500e-07
0.3715691.6650272.050136e-07
0.3734881.6645911.873538e-07
0.3754181.664161.696028e-07
0.3773571.6637351.517600e-07
0.3793061.6633151.338252e-07
0.381.6631671.274400e-07
0.3812651.6628991.227140e-07
0.3832351.6624891.153582e-07
0.3852141.6620841.079644e-07
0.3872041.6616831.005324e-07
0.3892041.6612879.306204e-08
0.391.6611329.009000e-08
0.3912151.6608968.707984e-08
0.3932361.6605098.207206e-08
0.3952671.6601277.703841e-08
0.3973091.659757.197876e-08
0.3993611.6593776.689298e-08
0.41.6592626.530900e-08
0.4014241.6590086.361451e-08
0.4034971.6586446.114657e-08
0.4051.6583835.935800e-08
0.4055821.6582835.901087e-08
0.4076771.6579275.776028e-08
0.4097821.6575755.650323e-08
0.4118991.6572285.523969e-08
0.4140271.6568845.396962e-08
0.4161651.6565445.269299e-08
0.4183151.6562085.140976e-08
0.421.6559485.040400e-08
0.4204761.6558765.020471e-08
0.4226481.6555474.929520e-08
0.4248311.6552224.838099e-08
0.4270261.6549014.746206e-08
0.4292311.6545844.653838e-08
0.4314491.654274.560993e-08
0.4336771.653964.467669e-08
0.4359171.6536534.373863e-08
0.4361.6536424.370400e-08
0.4381691.653354.296888e-08
0.4404321.653054.220179e-08
0.4427071.6527534.143074e-08
0.4449941.652464.065570e-08
0.4472931.652173.987666e-08
0.4496031.6518833.909360e-08
0.4519261.65163.830649e-08
0.454261.6513193.751532e-08
0.4566071.6510423.672006e-08
0.4589651.6507673.592069e-08
0.461.6506483.557000e-08
0.4613361.6504963.502370e-08
0.4637191.6502273.404928e-08
0.4661141.6499623.306982e-08
0.4685221.6496993.208531e-08
0.4709421.6494393.109571e-08
0.4733751.6491823.010101e-08
0.475821.6489282.910116e-08
0.4782781.6486762.809615e-08
0.4807481.6484282.708594e-08
0.4832321.6481812.607052e-08
0.4857281.6479382.504985e-08
0.4882371.6476972.402391e-08
0.4907591.6474582.299268e-08
0.4932941.6472232.195611e-08
0.4958421.6469892.091419e-08
0.4984031.6467581.986689e-08
0.51.6466161.921400e-08
0.5009781.646531.910232e-08
0.5035661.6463031.880675e-08
0.5061671.646081.850965e-08
0.5087811.6458581.821102e-08
0.5114091.6456391.791084e-08
0.5140511.6454221.760912e-08
0.5167061.6452071.730583e-08
0.5193761.6449951.700098e-08
0.5220581.6447841.669455e-08
0.5247551.6445761.638655e-08
0.5274661.644371.607695e-08
0.530191.6441661.576575e-08
0.5329291.6439641.545294e-08
0.5356821.6437641.513852e-08
0.5384491.6435671.482247e-08
0.541231.6433711.450479e-08
0.5440261.6431771.418548e-08
0.5461.6430421.396000e-08
0.5468361.6429851.398137e-08
0.5496611.6427951.405356e-08
0.55251.6426061.412613e-08
0.5553541.642421.419908e-08
0.5582231.6422351.427240e-08
0.5611061.6420531.434609e-08
0.5640041.6418721.442017e-08
0.5669181.6416921.449464e-08
0.5698461.6415151.456948e-08
0.572791.6413391.464472e-08
0.5757491.6411651.472034e-08
0.5787231.6409931.479635e-08
0.581.6409191.482900e-08
0.5817121.6408221.504325e-08
0.5847171.6406531.541930e-08
0.5877371.6404851.579730e-08
0.5907731.6403191.617725e-08
0.5938251.6401551.655916e-08
0.5968921.6399921.694305e-08
0.5999751.639831.732891e-08
0.6030741.639671.771677e-08
0.606191.6395121.810664e-08
0.6093211.6393551.849852e-08
0.6124681.6391991.889242e-08
0.6156321.6390451.928835e-08
0.6188121.6388921.968634e-08
0.621.6388361.983500e-08
0.6220091.6387411.979272e-08
0.6252221.6385911.972509e-08
0.6284511.6384421.965710e-08
0.6316971.6382951.958877e-08
0.634961.6381491.952008e-08
0.638241.6380041.945104e-08
0.6415371.637861.938164e-08
0.6448511.6377181.931189e-08
0.6481821.6375771.924177e-08
0.651531.6374371.917129e-08
0.6548961.6372981.910045e-08
0.6582781.6371611.902924e-08
0.661.6370911.899300e-08
0.6616791.6370241.875864e-08
0.6650971.6368891.828150e-08
0.6685321.6367551.780190e-08
0.6719861.6366221.731982e-08
0.6754571.636491.683525e-08
0.6789461.6363591.634818e-08
0.6824531.6362291.585859e-08
0.6859781.63611.536647e-08
0.6895211.6359721.487181e-08
0.6930831.6358461.437460e-08
0.6966631.635721.387481e-08
0.71.6356041.340900e-08
0.7002621.6355951.341402e-08
0.7038791.6354711.348331e-08
0.7075151.6353481.355295e-08
0.711171.6352271.362296e-08
0.7148431.6351061.369333e-08
0.7185361.6349851.376406e-08
0.7222471.6348661.383516e-08
0.7259781.6347481.390662e-08
0.7297281.634631.397846e-08
0.7334971.6345141.405066e-08
0.7372861.6343981.412324e-08
0.7410951.6342831.419619e-08
0.7449231.6341691.426952e-08
0.7487711.6340551.434323e-08
0.7526391.6339431.441732e-08
0.7565261.6338311.449179e-08
0.7604341.633721.456665e-08
0.7643621.6336091.464189e-08
0.768311.63351.471752e-08
0.7722791.6333911.479355e-08
0.7762681.6332831.486996e-08
0.7802781.6331751.494677e-08
0.7843091.6330681.502398e-08
0.788361.6329621.510158e-08
0.7924321.6328571.517959e-08
0.7965261.6327521.525800e-08
0.800641.6326471.533681e-08
0.8047761.6325441.541604e-08
0.8089331.6324411.549567e-08
0.8131111.6323381.557571e-08
0.8173111.6322361.565616e-08
0.8215331.6321351.573704e-08
0.8257771.6320341.581832e-08
0.8300421.6319341.590003e-08
0.834331.6318341.598216e-08
0.838641.6317351.606472e-08
0.8429721.6316361.614770e-08
0.8473261.6315381.623111e-08
0.8517031.631441.631495e-08
0.8561021.6313431.639923e-08
0.8605241.6312461.648394e-08
0.864971.631151.656908e-08
0.8694371.6310541.665467e-08
0.8739291.6309581.674070e-08
0.8784431.6308631.682717e-08
0.882981.6307691.691409e-08
0.8875411.6306751.700146e-08
0.8921261.6305811.708928e-08
0.8967341.6304871.717755e-08
0.9013661.6303941.726628e-08
0.9060221.6303011.735547e-08
0.9107021.6302091.744512e-08
0.9154071.6301171.753523e-08
0.9201351.6300251.762581e-08
0.9248881.6299331.771686e-08
0.9296661.6298421.780837e-08
0.9344681.6297511.790036e-08
0.9392951.6296611.799282e-08
0.9441471.629571.808577e-08
0.9490241.629481.817919e-08
0.9539261.629391.827309e-08
0.9588531.6293011.836748e-08
0.9638061.6292111.846236e-08
0.9687851.6291221.855772e-08
0.9737891.6290331.865358e-08
0.9788191.6289441.874994e-08
0.9838751.6288561.884679e-08
0.9889571.6287671.894414e-08
0.9940661.6286791.904199e-08
0.9992011.6285911.914036e-08
1.004361.6285031.923922e-08
1.009551.6284151.933860e-08
1.014761.6283281.943850e-08
1.020011.628241.953891e-08
1.025281.6281531.963983e-08
1.030571.6280651.974128e-08
1.035891.6279781.984325e-08
1.041251.6278911.994575e-08
1.046621.6278042.004878e-08
1.052031.6277172.015234e-08
1.057461.6276292.025644e-08
1.061.6275892.030500e-08
1.062931.6275422.110244e-08
1.068421.6274552.259814e-08
1.073941.6273692.410157e-08
1.079481.6272822.561277e-08
1.085061.6271952.713177e-08
1.090671.6271082.865862e-08
1.09631.6270213.019335e-08
1.101961.6269343.173602e-08
1.107651.6268463.328665e-08
1.113381.6267593.484529e-08
1.119131.6266723.641199e-08
1.124911.6265853.798677e-08
1.130721.6264983.956969e-08
1.136561.626414.116079e-08
1.142431.6263234.276010e-08
1.148331.6262354.436768e-08
1.154261.6261474.598356e-08
1.160231.6260594.760779e-08
1.166221.6259714.924041e-08
1.172241.6258835.088146e-08
1.17831.6257945.253099e-08
1.184381.6257065.418903e-08
1.19051.6256175.585565e-08
1.196651.6255285.753087e-08
1.202831.6254395.921474e-08
1.209051.625356.090732e-08
1.215291.625266.260863e-08
1.221571.625176.431874e-08
1.227881.625086.603767e-08
1.234221.624996.776549e-08
1.24061.6248996.950223e-08
1.2471.6248087.124795e-08
1.253451.6247177.300268e-08
1.259921.6246267.476647e-08
1.266431.6245347.653938e-08
1.272971.6244427.832144e-08
1.279551.6243498.011271e-08
1.286161.6242578.191323e-08
1.29281.6241638.372305e-08
1.299481.624078.554222e-08
1.306191.6239768.737079e-08
1.312941.6238828.920880e-08
1.319721.6237879.105631e-08
1.326541.6236929.291336e-08
1.333391.6235979.478000e-08
1.340281.6235019.665629e-08
1.34721.6234049.854227e-08
1.354161.6233081.004380e-07
1.361151.623211.023435e-07
1.368181.6231131.042589e-07
1.375251.6230141.061841e-07
1.382351.6229161.081193e-07
1.38951.6228161.100645e-07
1.396671.6227171.120197e-07
1.403891.6226161.139851e-07
1.411141.6225161.159605e-07
1.418431.6224141.179462e-07
1.425761.6223121.199422e-07
1.433121.622211.219484e-07
1.440521.6221061.239651e-07
1.447961.6220031.259921e-07
1.455441.6218981.280296e-07
1.462961.6217931.300777e-07
1.470521.6216881.321363e-07
1.478111.6215811.342055e-07
1.485751.6214741.362855e-07
1.493421.6213671.383761e-07
1.501141.6212581.404776e-07
1.508891.6211491.425900e-07
1.516691.6210391.447132e-07
1.524521.6209291.468474e-07
1.531.6208511.483400e-07
1.53241.6208181.522872e-07
1.540311.6207051.653287e-07
1.548271.6205931.784375e-07
1.556271.6204791.916140e-07
1.56431.6203652.048586e-07
1.572381.6202492.181716e-07
1.580511.6201332.315534e-07
1.588671.6200162.450043e-07
1.596881.6198982.585247e-07
1.605131.619782.721149e-07
1.613421.619662.857753e-07
1.621751.619542.995063e-07
1.630131.6194183.133082e-07
1.638551.6192963.271814e-07
1.647011.6191733.411262e-07
1.655521.6190483.551431e-07
1.664071.6189233.692324e-07
1.672671.6187973.833945e-07
1.681311.618673.976297e-07
1.689991.6185414.119385e-07
1.698721.6184124.263211e-07
1.70751.6182824.407781e-07
1.716321.618154.553098e-07
1.725181.6180184.699165e-07
1.734091.6178844.845986e-07
1.743051.6177494.993566e-07
1.752061.6176135.141908e-07
1.761111.6174765.291017e-07
1.77021.6173375.440896e-07
1.779351.6171985.591549e-07
1.788541.6170575.742980e-07
1.797781.6169155.895193e-07
1.807061.6167726.048193e-07
1.81641.6166276.201983e-07
1.825781.6164816.356567e-07
1.835211.6163346.511950e-07
1.844691.6161866.668135e-07
1.854221.6160366.825128e-07
1.86381.6158856.982931e-07
1.873421.6157327.141549e-07
1.88311.6155787.300987e-07
1.892831.6154237.461248e-07
1.902611.6152667.622337e-07
1.912431.6151077.784258e-07
1.922311.6149477.947016e-07
1.932241.6147868.110614e-07
1.942221.6146238.275058e-07
1.952261.6144588.440350e-07
1.962341.6142928.606497e-07
1.971.6141658.732700e-07
1.972481.6141249.040065e-07
1.982671.6139551.030463e-06
1.992911.6137841.157573e-06
2.00321.6136111.285340e-06
2.013551.6134371.413767e-06
2.023951.6132611.542857e-06
2.03441.6130831.672613e-06
2.044911.6129031.803041e-06
2.055481.6127211.934141e-06
2.066091.6125382.065919e-06
2.076771.6123532.198378e-06
2.087491.6121662.331521e-06
2.098281.6119772.465352e-06
2.109111.6117862.599874e-06
2.120011.6115932.735090e-06
2.130961.6113982.871006e-06
2.141971.6112013.007623e-06
2.153031.6110023.144946e-06
2.164151.6108013.282978e-06
2.175331.6105983.421724e-06
2.186571.6103933.561186e-06
2.197861.6101863.701368e-06
2.209221.6099763.842275e-06
2.220631.6097643.983909e-06
2.23211.609554.126275e-06
2.243631.6093344.269377e-06
2.255221.6091154.413217e-06
2.266871.6088944.557801e-06
2.278581.6086714.703132e-06
2.290351.6084454.849213e-06
2.302181.6082164.996048e-06
2.314071.6079865.143643e-06
2.3251.6077725.279300e-06
2.326021.6077525.321045e-06
2.338041.6075165.811238e-06
2.350121.6072786.303964e-06
2.362251.6070376.799234e-06
2.374461.6067937.297063e-06
2.386721.6065467.797463e-06
2.399051.6062978.300448e-06
2.411441.6060458.806032e-06
2.42391.605799.314227e-06
2.436421.6055329.825047e-06
2.449011.6052721.033851e-05
2.461661.6050081.085462e-05
2.474371.6047411.137339e-05
2.487151.6044721.189485e-05
2.51.6041991.241900e-05

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
—