Optical constants

Refractive index of N-LAK7 (SCHOTT)

N-LAK7: n,k 0.29–2.5 µm

Data
formula 2 + tabulated k
Range
0.29–2.5 µm
Temperature
293 K
Licence
CC0-1.0

Plot

Click the plot to set the calculator wavelength. Note: k data cover 300-2500 nm only; k = 0 elsewhere in the n range 290-2500 nm.

At one wavelength

Range 0.29–2.5 µm
Refractive index n
1.6516
Extinction coefficient k
9.37538e-09
Permittivity ε1
2.72777
Permittivity ε2
3.09687e-08
Absorption coefficient α
0.00200501 cm⁻¹
Penetration depth δ = λ/(2πk)
9.97501e+09 nm
Abbe number Vd
58.518
Chromatic dispersion dn/dλ
-0.0575255 µm⁻¹
Group index ng
1.6854
Group velocity dispersion
100.514 fs²/mm
Dispersion parameter D
-548.356 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-LAK7 (SCHOTT): N-LAK7
schott_n_lak7 = ls.fetch_refractiveindex("specs", "SCHOTT-optical", "N-LAK7", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(schott_n_lak7.range_nm)  # (290, 2500) nm
eps = schott_n_lak7.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=1.23679889λ2λ2−0.00610105538+0.445051837λ2λ2−0.0201388334+1.01745888λ2λ2−90.638038

Valid from 0.29 to 2.5 µm.

Coefficients as stored
CiValue
C10.0
C21.23679889
C30.00610105538
C40.445051837
C50.0201388334
C61.01745888
C790.638038

Comments and conditions

Conditions

temperature
293 K

Properties

thermal dispersion
type: formula A, coefficients: -3.4e-06 1.17e-08 2.38e-11 4.96e-07 4.44e-10 0.107
nd
1.6516
Vd
58.52
glass code
652585.384
glass status
standard
density
value: 3840
thermal expansion
value: 7.1e-06, temperature range: 243 343; value: 8.2e-06, temperature range: 293 573
dPgF
-0.0021
resistance
acid: 53.3; stain: 2.0; alkali: 3.3; climatic: 3.0; phosphate: 4.3

Thermo-optic coefficient

  • Schott thermal-dispersion model (reference temperature 293.0 K): dn/dT = -1.11e-06 K⁻¹ at 633 nm, dn/dT = -1.59e-06 K⁻¹ at 1310 nm, dn/dT = -1.63e-06 K⁻¹ at 1550 nm
Notes on the source data (kept exactly as published):
  • k data cover 300-2500 nm only; k = 0 elsewhere in the n range 290-2500 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 424 wavelengths, the same grid as the API and the library
N-LAK7 (SCHOTT), N-LAK7: n and k versus wavelength
λ (µm)nk
0.291.708150
0.291571.7072420
0.2931481.7063470
0.2947351.7054660
0.2963311.7045980
0.2979351.7037430
0.2995481.70290
0.31.7026663.948800e-06
0.301171.7020693.740661e-06
0.30281.7012513.450501e-06
0.3044391.7004443.158771e-06
0.3060871.6996492.865461e-06
0.3077441.6988662.570564e-06
0.309411.6980942.274070e-06
0.311.6978242.169100e-06
0.3110851.6973322.066431e-06
0.3127691.6965821.907102e-06
0.3144621.6958421.746911e-06
0.3161651.6951131.585852e-06
0.3178761.6943941.423921e-06
0.3195971.6936851.261113e-06
0.321.6935211.223000e-06
0.3213271.6929861.163710e-06
0.3230671.6922971.086006e-06
0.3248161.6916171.007881e-06
0.3265741.6909469.293340e-07
0.3283421.6902858.503613e-07
0.330121.6896337.709612e-07
0.3319071.688996.911312e-07
0.3337031.6883556.108690e-07
0.3341.6882525.976200e-07
0.335511.687735.666735e-07
0.3373261.6871125.294475e-07
0.3391521.6865034.920201e-07
0.3409881.6859024.543900e-07
0.3428341.685314.165563e-07
0.344691.6847253.785177e-07
0.3465561.6841483.402732e-07
0.3484321.6835783.018216e-07
0.351.6831112.696900e-07
0.3503191.6830162.667276e-07
0.3522151.6824622.490894e-07
0.3541221.6819152.313556e-07
0.3560391.6813752.135258e-07
0.3579661.6808421.955995e-07
0.3599041.6803161.775762e-07
0.3618521.6797971.594553e-07
0.3638111.6792841.412363e-07
0.3651.6789781.301800e-07
0.3657811.6787791.257876e-07
0.3677611.6782791.146473e-07
0.3697521.6777871.034466e-07
0.371.6777261.020500e-07
0.3717531.67739.615430e-08
0.3737661.676828.938750e-08
0.3757891.6763458.258407e-08
0.3778241.6758777.574381e-08
0.3798691.6754156.886652e-08
0.381.6753866.842600e-08
0.3819251.6749596.475963e-08
0.3839931.6745086.082259e-08
0.3860721.6740635.686423e-08
0.3881621.6736245.288445e-08
0.391.6732444.938400e-08
0.3902631.673194.910513e-08
0.3923761.6727614.686525e-08
0.39451.6723384.461325e-08
0.3966351.671924.234905e-08
0.3987831.6715074.007260e-08
0.41.6712773.878200e-08
0.4009411.67113.812371e-08
0.4031121.6706973.660609e-08
0.4051.6703533.528600e-08
0.4052941.67033.520404e-08
0.4074881.6699073.459292e-08
0.4096941.6695193.397849e-08
0.4119121.6691353.336074e-08
0.4141421.6687573.273964e-08
0.4163841.6683833.211518e-08
0.4186381.6680133.148734e-08
0.421.6677933.110800e-08
0.4209041.6676483.093447e-08
0.4231831.6672873.049727e-08
0.4254741.6669313.005770e-08
0.4277771.6665792.961575e-08
0.4300931.6662312.917141e-08
0.4324211.6658872.872467e-08
0.4347621.6655482.827551e-08
0.4361.665372.803800e-08
0.4371161.6652122.783247e-08
0.4394821.664882.739657e-08
0.4418611.6645532.695831e-08
0.4442531.6642292.651768e-08
0.4466581.6639092.607466e-08
0.4490761.6635922.562925e-08
0.4515071.663282.518143e-08
0.4539521.6629712.473118e-08
0.4564091.6626652.427849e-08
0.458881.6623632.382335e-08
0.461.6622282.361700e-08
0.4613641.6620652.324761e-08
0.4638621.661772.257120e-08
0.4663731.6614782.189113e-08
0.4688971.661192.120737e-08
0.4714361.6609052.051991e-08
0.4739881.6606231.982873e-08
0.4765541.6603451.913381e-08
0.4791341.6600691.843513e-08
0.4817271.6597971.773267e-08
0.4843351.6595281.702640e-08
0.4869571.6592621.631631e-08
0.4895931.6589991.560238e-08
0.4922441.6587381.488458e-08
0.4949091.6584811.416289e-08
0.4975881.6582261.343730e-08
0.51.6580011.278400e-08
0.5002811.6579751.275908e-08
0.502991.6577261.251932e-08
0.5057131.657481.227827e-08
0.508451.6572361.203591e-08
0.5112031.6569961.179223e-08
0.513971.6567581.154724e-08
0.5167531.6565221.130092e-08
0.519551.6562891.105327e-08
0.5223631.6560591.080427e-08
0.525191.6558311.055393e-08
0.5280341.6556051.030223e-08
0.5308921.6553821.004917e-08
0.5337661.6551619.794745e-09
0.5366561.6549439.538938e-09
0.5395611.6547279.281747e-09
0.5424821.6545139.023163e-09
0.5454191.6543028.763179e-09
0.5461.654268.711700e-09
0.5483711.6540928.749526e-09
0.551341.6538858.796885e-09
0.5543241.653688.844499e-09
0.5573251.6534788.892371e-09
0.5603421.6532778.940503e-09
0.5633761.6530788.988895e-09
0.5664261.6528829.037549e-09
0.5694921.6526879.086466e-09
0.5725751.6524959.135648e-09
0.5756751.6523049.185096e-09
0.5787911.6521159.234812e-09
0.581.6520439.254100e-09
0.5819241.6519299.284806e-09
0.5850751.6517449.335077e-09
0.5882421.6515619.385619e-09
0.5914261.6513799.436435e-09
0.5946281.65129.487526e-09
0.5978471.6510229.538893e-09
0.6010831.6508469.590539e-09
0.6043371.6506729.642464e-09
0.6076091.65059.694671e-09
0.6108981.6503299.747160e-09
0.6142051.650169.799933e-09
0.617531.6499929.852992e-09
0.621.6498699.892400e-09
0.6208731.6498269.860254e-09
0.6242351.6496629.736548e-09
0.6276141.6494999.612173e-09
0.6310111.6493389.487125e-09
0.6344271.6491789.361399e-09
0.6378621.649029.234993e-09
0.6413151.6488639.107903e-09
0.6447871.6487088.980125e-09
0.6482771.6485548.851655e-09
0.6517871.6484028.722489e-09
0.6553151.648258.592624e-09
0.6588631.6481018.462056e-09
0.661.6480538.420200e-09
0.662431.6479528.315391e-09
0.6660161.6478058.160688e-09
0.6696211.6476598.005147e-09
0.6732461.6475157.848765e-09
0.6768911.6473727.691536e-09
0.6805551.647237.533456e-09
0.6842391.6470897.374519e-09
0.6879431.6469497.214723e-09
0.6916681.6468117.054062e-09
0.6954121.6466746.892530e-09
0.6991771.6465386.730125e-09
0.71.6465086.694600e-09
0.7029621.6464036.695096e-09
0.7067671.6462696.695733e-09
0.7105931.6461366.696374e-09
0.714441.6460056.697019e-09
0.7183081.6458746.697667e-09
0.7221961.6457456.698318e-09
0.7261061.6456166.698973e-09
0.7300361.6454896.699631e-09
0.7339891.6453626.700293e-09
0.7379621.6452376.700959e-09
0.7419571.6451126.701628e-09
0.7459741.6449886.702301e-09
0.7500121.6448666.702977e-09
0.7540721.6447446.703657e-09
0.7581541.6446236.704341e-09
0.7622591.6445036.705028e-09
0.7663851.6443846.705719e-09
0.7705341.6442666.706414e-09
0.7747051.6441486.707113e-09
0.7788991.6440316.707816e-09
0.7831161.6439166.708522e-09
0.7873551.6438016.709232e-09
0.7916171.6436866.709946e-09
0.7959031.6435736.710664e-09
0.8002111.643466.711385e-09
0.8045431.6433486.712111e-09
0.8088991.6432366.712841e-09
0.8132781.6431266.713574e-09
0.817681.6430166.714311e-09
0.8221071.6429076.715053e-09
0.8265571.6427986.715798e-09
0.8310321.642696.716548e-09
0.8355311.6425836.717301e-09
0.8400541.6424766.718059e-09
0.8446021.642376.718821e-09
0.8491741.6422646.719587e-09
0.8537711.6421596.720357e-09
0.8583931.6420556.721131e-09
0.863041.6419516.721909e-09
0.8677121.6418476.722692e-09
0.8724091.6417456.723479e-09
0.8771321.6416426.724270e-09
0.881881.641546.725065e-09
0.8866541.6414396.725865e-09
0.8914541.6413386.726669e-09
0.896281.6412386.727477e-09
0.9011321.6411386.728290e-09
0.9060111.6410386.729107e-09
0.9109151.6409396.729928e-09
0.9158461.6408416.730754e-09
0.9208041.6407426.731585e-09
0.9257891.6406446.732420e-09
0.9308011.6405476.733259e-09
0.935841.640456.734103e-09
0.9409061.6403536.734952e-09
0.9461.6402566.735805e-09
0.9511211.640166.736663e-09
0.956271.6400646.737525e-09
0.9614471.6399686.738392e-09
0.9666511.6398736.739264e-09
0.9718841.6397786.740141e-09
0.9771461.6396836.741022e-09
0.9824351.6395896.741908e-09
0.9877541.6394946.742799e-09
0.9931011.63946.743694e-09
0.9984771.6393076.744595e-09
1.003881.6392136.745500e-09
1.009321.6391196.746411e-09
1.014781.6390266.747326e-09
1.020271.6389336.748246e-09
1.02581.638846.749171e-09
1.031351.6387476.750101e-09
1.036931.6386546.751036e-09
1.042551.6385626.751977e-09
1.048191.6384696.752922e-09
1.053871.6383776.753873e-09
1.059571.6382856.754828e-09
1.061.6382786.754900e-09
1.065311.6381938.240333e-09
1.071071.63819.854556e-09
1.076871.6380081.147752e-08
1.08271.6379161.310927e-08
1.088561.6378241.474985e-08
1.094461.6377321.639931e-08
1.100381.637641.805770e-08
1.106341.6375481.972507e-08
1.112331.6374562.140147e-08
1.118351.6373642.308694e-08
1.12441.6372722.478153e-08
1.130491.637182.648530e-08
1.136611.6370872.819829e-08
1.142761.6369952.992056e-08
1.148951.6369033.165215e-08
1.155171.636813.339311e-08
1.161421.6367183.514350e-08
1.167711.6366253.690336e-08
1.174031.6365323.867275e-08
1.180391.6364394.045172e-08
1.186781.6363464.224032e-08
1.19321.6362524.403861e-08
1.199661.6361594.584662e-08
1.206161.6360654.766443e-08
1.212681.6359714.949207e-08
1.219251.6358775.132961e-08
1.225851.6357835.317710e-08
1.232491.6356885.503459e-08
1.239161.6355935.690213e-08
1.245871.6354985.877979e-08
1.252611.6354036.066761e-08
1.259391.6353076.256565e-08
1.266211.6352116.447396e-08
1.273061.6351156.639260e-08
1.279961.6350186.832164e-08
1.286891.6349217.026111e-08
1.293851.6348247.221108e-08
1.300861.6347267.417161e-08
1.30791.6346287.614275e-08
1.314981.6345297.812457e-08
1.32211.634438.011711e-08
1.329251.6343318.212044e-08
1.336451.6342318.413461e-08
1.343691.6341318.615969e-08
1.350961.6340318.819573e-08
1.358271.633939.024279e-08
1.365631.6338289.230094e-08
1.373021.6337269.437022e-08
1.380451.6336239.645071e-08
1.387921.633529.854246e-08
1.395441.6334171.006455e-07
1.402991.6333131.027600e-07
1.410591.6332081.048859e-07
1.418221.6331031.070233e-07
1.42591.6329971.091723e-07
1.433621.632891.113329e-07
1.441381.6327831.135052e-07
1.449181.6326751.156893e-07
1.457031.6325671.178852e-07
1.464921.6324581.200930e-07
1.472851.6323481.223127e-07
1.480821.6322381.245445e-07
1.488841.6321271.267883e-07
1.49691.6320151.290443e-07
1.5051.6319031.313125e-07
1.513151.6317891.335930e-07
1.521341.6316751.358858e-07
1.529581.631561.381910e-07
1.531.6315551.383100e-07
1.537861.6314451.523358e-07
1.546181.6313281.672004e-07
1.554551.6312111.821455e-07
1.562971.6310931.971715e-07
1.571431.6309742.122789e-07
1.579931.6308542.274680e-07
1.588491.6307342.427394e-07
1.597091.6306122.580934e-07
1.605731.630492.735306e-07
1.614431.6303662.890513e-07
1.623161.6302423.046561e-07
1.631951.6301173.203453e-07
1.640791.629993.361194e-07
1.649671.6298633.519790e-07
1.65861.6297343.679244e-07
1.667581.6296053.839561e-07
1.676611.6294754.000747e-07
1.685681.6293434.162804e-07
1.694811.629214.325739e-07
1.703981.6290774.489556e-07
1.713211.6289424.654260e-07
1.722481.6288064.819856e-07
1.731811.6286694.986348e-07
1.741181.628535.153741e-07
1.750611.6283915.322041e-07
1.760081.628255.491251e-07
1.769611.6281085.661378e-07
1.779191.6279645.832425e-07
1.788821.627826.004399e-07
1.798511.6276746.177304e-07
1.808241.6275276.351144e-07
1.818031.6273786.525926e-07
1.827871.6272286.701654e-07
1.837771.6270776.878333e-07
1.847721.6269247.055968e-07
1.857721.626777.234566e-07
1.867781.6266147.414130e-07
1.877891.6264577.594666e-07
1.888061.6262987.776179e-07
1.898281.6261387.958675e-07
1.908551.6259768.142159e-07
1.918881.6258138.326637e-07
1.929271.6256488.512113e-07
1.939721.6254818.698593e-07
1.950221.6253138.886082e-07
1.960771.6251439.074587e-07
1.971.6249949.239300e-07
1.971391.6249729.407433e-07
1.982061.6247981.069866e-06
1.992791.6246231.199688e-06
2.003581.6244461.330213e-06
2.014431.6242681.461444e-06
2.025331.6240871.593386e-06
2.03631.6239051.726042e-06
2.047321.6237211.859416e-06
2.05841.6235351.993512e-06
2.069551.6233462.128335e-06
2.080751.6231562.263887e-06
2.092011.6229642.400172e-06
2.103341.622772.537196e-06
2.114721.6225742.674961e-06
2.126171.6223762.813473e-06
2.137681.6221762.952734e-06
2.149251.6219733.092748e-06
2.160891.6217683.233521e-06
2.172591.6215613.375056e-06
2.184351.6213523.517357e-06
2.196171.6211413.660429e-06
2.208061.6209273.804275e-06
2.220021.6207113.948899e-06
2.232031.6204924.094307e-06
2.244121.6202714.240502e-06
2.256271.6200484.387488e-06
2.268481.6198224.535270e-06
2.280761.6195944.683852e-06
2.293111.6193634.833238e-06
2.305521.6191294.983433e-06
2.3181.6188935.134441e-06
2.3251.618765.219100e-06
2.330551.6186545.431225e-06
2.343171.6184125.913311e-06
2.355851.6181686.398006e-06
2.368611.617926.885326e-06
2.381431.617677.375284e-06
2.394321.6174177.867894e-06
2.407281.6171618.363171e-06
2.420311.6169038.861129e-06
2.433421.6166419.361782e-06
2.446591.6163769.865146e-06
2.459831.6161071.037124e-05
2.473151.6158361.088006e-05
2.486541.6155621.139165e-05
2.51.6152841.190600e-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
—