Optical constants

Refractive index of LAKL12 (SCHOTT)

LAKL12: 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
1.6779
Extinction coefficient k
1.50234e-08
Permittivity ε1
2.81534
Permittivity ε2
5.04154e-08
Absorption coefficient α
0.00321289 cm⁻¹
Penetration depth δ = λ/(2πk)
6.22493e+09 nm
Abbe number Vd
54.924
Chromatic dispersion dn/dλ
-0.0637063 µm⁻¹
Group index ng
1.71533
Group velocity dispersion
111.864 fs²/mm
Dispersion parameter D
-610.278 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

# LAKL12 (SCHOTT): LAKL12
schott_lakl12 = ls.fetch_refractiveindex("specs", "SCHOTT-optical", "LAKL12", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(schott_lakl12.range_nm)  # (320, 2500) nm
eps = schott_lakl12.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=1.28115389λ2λ2−0.00636439821+0.482607607λ2λ2−0.0213764262+1.16553538λ2λ2−93.2771532

Valid from 0.32 to 2.5 µm.

Coefficients as stored
CiValue
C10.0
C21.28115389
C30.00636439821
C40.482607607
C50.0213764262
C61.16553538
C793.2771532

Comments and conditions

was replaced by N-LAK12

Conditions

temperature
293 K

Properties

thermal dispersion
type: formula A, coefficients: 2.26e-06 1.05e-08 -8.4e-12 4.57e-07 5.86e-10 0.21
nd
1.6779
Vd
54.92
glass code
678549.332
glass status
preferred
density
value: 3320
thermal expansion
value: 6.8e-06, temperature range: 243 343; value: 8e-06, temperature range: 293 573
dPgF
-0.0062
resistance
acid: 53.3; stain: 3.0; alkali: 2.2; climatic: 3.0; phosphate: 3.3

Thermo-optic coefficient

  • Schott thermal-dispersion model (reference temperature 293.0 K): dn/dT = 1.91e-06 K⁻¹ at 633 nm, dn/dT = 1.34e-06 K⁻¹ at 1310 nm, dn/dT = 1.29e-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
LAKL12 (SCHOTT), LAKL12: n and k versus wavelength
λ (µm)nk
0.321.7247352.572700e-06
0.3216531.7239852.448079e-06
0.3233141.7232452.322814e-06
0.3249851.7225162.196902e-06
0.3266631.7217962.070340e-06
0.3283511.7210861.943124e-06
0.3300471.7203851.815251e-06
0.3317521.7196941.686717e-06
0.3334651.7190121.557519e-06
0.3341.7188011.517200e-06
0.3351881.7183391.455534e-06
0.3369191.7176741.365639e-06
0.3386591.7170191.275280e-06
0.3404091.7163721.184454e-06
0.3421671.7157331.093159e-06
0.3439351.7151031.001392e-06
0.3457111.7144819.091519e-07
0.3474971.7138678.164348e-07
0.3492921.7132617.232388e-07
0.351.7130256.864800e-07
0.3510961.7126636.585016e-07
0.352911.7120736.122166e-07
0.3547331.711495.656924e-07
0.3565651.7109145.189279e-07
0.3584071.7103464.719219e-07
0.3602581.7097854.246730e-07
0.3621191.7092313.771801e-07
0.363991.7086843.294419e-07
0.3651.7083923.036600e-07
0.365871.7081432.914908e-07
0.367761.707612.650549e-07
0.369661.7070832.384825e-07
0.371.706992.337200e-07
0.3715691.7065632.191659e-07
0.3734881.7060492.013622e-07
0.3754181.7055421.834664e-07
0.3773571.7050411.654783e-07
0.3793061.7045461.473972e-07
0.381.7043711.409600e-07
0.3812651.7040571.345232e-07
0.3832351.7035741.245048e-07
0.3852141.7030971.144346e-07
0.3872041.7026251.043124e-07
0.3892041.702169.413786e-08
0.391.7019779.009000e-08
0.3912151.70178.659214e-08
0.3932361.7012458.077300e-08
0.3952671.7007977.492380e-08
0.3973091.7003536.904439e-08
0.3993611.6999156.313461e-08
0.41.699786.129400e-08
0.4014241.6994825.959125e-08
0.4034971.6990545.711128e-08
0.4051.6987485.531400e-08
0.4055821.6986315.496242e-08
0.4076771.6982135.369576e-08
0.4097821.6978015.242257e-08
0.4118991.6973935.114279e-08
0.4140271.6969894.985641e-08
0.4161651.6965914.856338e-08
0.4183151.6961974.726368e-08
0.421.6958934.624500e-08
0.4204761.6958084.612682e-08
0.4226481.6954234.558750e-08
0.4248311.6950434.504538e-08
0.4270261.6946674.450047e-08
0.4292311.6942964.395275e-08
0.4314491.6939294.340219e-08
0.4336771.6935664.284879e-08
0.4359171.6932074.229253e-08
0.4361.6931944.227200e-08
0.4381691.6928524.153082e-08
0.4404321.6925024.075741e-08
0.4427071.6921553.998001e-08
0.4449941.6918123.919859e-08
0.4472931.6914733.841314e-08
0.4496031.6911383.762362e-08
0.4519261.6908073.683003e-08
0.454261.6904793.603234e-08
0.4566071.6901553.523053e-08
0.4589651.6898353.442458e-08
0.461.6896963.407100e-08
0.4613361.6895183.352099e-08
0.4637191.6892053.253996e-08
0.4661141.6888953.155386e-08
0.4685221.6885893.056266e-08
0.4709421.6882862.956635e-08
0.4733751.6879872.856489e-08
0.475821.687692.755826e-08
0.4782781.6873972.654642e-08
0.4807481.6871072.552937e-08
0.4832321.6868212.450705e-08
0.4857281.6865372.347946e-08
0.4882371.6862562.244656e-08
0.4907591.6859792.140832e-08
0.4932941.6857042.036472e-08
0.4958421.6854331.931573e-08
0.4984031.6851641.826132e-08
0.51.6849991.760400e-08
0.5009781.6848981.750792e-08
0.5035661.6846351.725364e-08
0.5061671.6843751.699805e-08
0.5087811.6841171.674114e-08
0.5114091.6838631.648290e-08
0.5140511.6836111.622332e-08
0.5167061.6833611.596241e-08
0.5193761.6831141.570015e-08
0.5220581.682871.543653e-08
0.5247551.6826291.517155e-08
0.5274661.6823891.490520e-08
0.530191.6821531.463748e-08
0.5329291.6819181.436837e-08
0.5356821.6816861.409788e-08
0.5384491.6814571.382598e-08
0.541231.681231.355269e-08
0.5440261.6810051.327798e-08
0.5461.6808481.308400e-08
0.5468361.6807821.312691e-08
0.5496611.6805621.327188e-08
0.55251.6803441.341760e-08
0.5553541.6801281.356408e-08
0.5582231.6799141.371131e-08
0.5611061.6797031.385930e-08
0.5640041.6794931.400805e-08
0.5669181.6792861.415758e-08
0.5698461.679081.430787e-08
0.572791.6788771.445895e-08
0.5757491.6786751.461080e-08
0.5787231.6784761.476344e-08
0.581.6783911.482900e-08
0.5817121.6782781.487278e-08
0.5847171.6780831.494963e-08
0.5877371.6778891.502688e-08
0.5907731.6776971.510452e-08
0.5938251.6775071.518257e-08
0.5968921.6773191.526102e-08
0.5999751.6771331.533987e-08
0.6030741.6769481.541913e-08
0.606191.6767651.549880e-08
0.6093211.6765841.557888e-08
0.6124681.6764041.565938e-08
0.6156321.6762261.574029e-08
0.6188121.676051.582162e-08
0.621.6759851.585200e-08
0.6220091.6758751.579707e-08
0.6252221.6757021.570919e-08
0.6284511.6755311.562086e-08
0.6316971.6753611.553208e-08
0.634961.6751931.544283e-08
0.638241.6750261.535313e-08
0.6415371.6748611.526296e-08
0.6448511.6746971.517233e-08
0.6481821.6745341.508122e-08
0.651531.6743731.498965e-08
0.6548961.6742141.489761e-08
0.6582781.6740551.480508e-08
0.661.6739761.475800e-08
0.6616791.6738981.479552e-08
0.6650971.6737431.487191e-08
0.6685321.6735891.494870e-08
0.6719861.6734361.502588e-08
0.6754571.6732841.510346e-08
0.6789461.6731341.518144e-08
0.6824531.6729851.525982e-08
0.6859781.6728371.533861e-08
0.6895211.672691.541780e-08
0.6930831.6725451.549741e-08
0.6966631.6724011.557742e-08
0.71.6722681.565200e-08
0.7002621.6722581.566033e-08
0.7038791.6721161.577536e-08
0.7075151.6719751.589100e-08
0.711171.6718351.600722e-08
0.7148431.6716961.612405e-08
0.7185361.6715591.624148e-08
0.7222471.6714221.635952e-08
0.7259781.6712871.647817e-08
0.7297281.6711521.659743e-08
0.7334971.6710191.671731e-08
0.7372861.6708871.683781e-08
0.7410951.6707551.695893e-08
0.7449231.6706251.708067e-08
0.7487711.6704951.720304e-08
0.7526391.6703661.732605e-08
0.7565261.6702391.744969e-08
0.7604341.6701121.757397e-08
0.7643621.6699861.769889e-08
0.768311.6698611.782446e-08
0.7722791.6697371.795068e-08
0.7762681.6696131.807754e-08
0.7802781.6694911.820507e-08
0.7843091.6693691.833325e-08
0.788361.6692481.846209e-08
0.7924321.6691281.859160e-08
0.7965261.6690081.872178e-08
0.800641.668891.885263e-08
0.8047761.6687721.898416e-08
0.8089331.6686541.911636e-08
0.8131111.6685381.924925e-08
0.8173111.6684221.938283e-08
0.8215331.6683071.951709e-08
0.8257771.6681931.965205e-08
0.8300421.6680791.978771e-08
0.834331.6679661.992406e-08
0.838641.6678532.006113e-08
0.8429721.6677412.019889e-08
0.8473261.667632.033738e-08
0.8517031.6675192.047657e-08
0.8561021.6674092.061649e-08
0.8605241.6672992.075712e-08
0.864971.667192.089849e-08
0.8694371.6670822.104058e-08
0.8739291.6669742.118341e-08
0.8784431.6668662.132698e-08
0.882981.6667592.147129e-08
0.8875411.6666532.161634e-08
0.8921261.6665472.176214e-08
0.8967341.6664412.190870e-08
0.9013661.6663362.205601e-08
0.9060221.6662322.220408e-08
0.9107021.6661272.235292e-08
0.9154071.6660232.250253e-08
0.9201351.665922.265291e-08
0.9248881.6658172.280407e-08
0.9296661.6657142.295600e-08
0.9344681.6656122.310873e-08
0.9392951.665512.326224e-08
0.9441471.6654092.341654e-08
0.9490241.6653072.357164e-08
0.9539261.6652062.372755e-08
0.9588531.6651062.388425e-08
0.9638061.6650052.404177e-08
0.9687851.6649052.420010e-08
0.9737891.6648062.435925e-08
0.9788191.6647062.451922e-08
0.9838751.6646072.468002e-08
0.9889571.6645082.484165e-08
0.9940661.6644092.500411e-08
0.9992011.664312.516741e-08
1.004361.6642122.533156e-08
1.009551.6641142.549655e-08
1.014761.6640162.566240e-08
1.020011.6639182.582910e-08
1.025281.663822.599666e-08
1.030571.6637232.616509e-08
1.035891.6636262.633439e-08
1.041251.6635282.650457e-08
1.046621.6634312.667562e-08
1.052031.6633342.684755e-08
1.057461.6632372.702038e-08
1.061.6631922.710100e-08
1.062931.663142.748317e-08
1.068421.6630442.819997e-08
1.073941.6629472.892048e-08
1.079481.662852.964472e-08
1.085061.6627543.037269e-08
1.090671.6626573.110442e-08
1.09631.662563.183993e-08
1.101961.6624643.257925e-08
1.107651.6623673.332238e-08
1.113381.6622713.406935e-08
1.119131.6621743.482018e-08
1.124911.6620773.557488e-08
1.130721.6619813.633349e-08
1.136561.6618843.709601e-08
1.142431.6617873.786247e-08
1.148331.661693.863289e-08
1.154261.6615933.940730e-08
1.160231.6614964.018570e-08
1.166221.6613994.096812e-08
1.172241.6613014.175458e-08
1.17831.6612044.254511e-08
1.184381.6611064.333972e-08
1.19051.6610084.413843e-08
1.196651.660914.494127e-08
1.202831.6608124.574826e-08
1.209051.6607144.655941e-08
1.215291.6606154.737476e-08
1.221571.6605164.819432e-08
1.227881.6604174.901811e-08
1.234221.6603184.984615e-08
1.24061.6602185.067848e-08
1.2471.6601185.151510e-08
1.253451.6600185.235604e-08
1.259921.6599185.320133e-08
1.266431.6598175.405099e-08
1.272971.6597165.490503e-08
1.279551.6596155.576348e-08
1.286161.6595135.662637e-08
1.29281.6594115.749372e-08
1.299481.6593095.836554e-08
1.306191.6592065.924187e-08
1.312941.6591036.012273e-08
1.319721.6596.100814e-08
1.326541.6588966.189812e-08
1.333391.6587926.279270e-08
1.340281.6586876.369189e-08
1.34721.6585826.459574e-08
1.354161.6584766.550425e-08
1.361151.658376.641745e-08
1.368181.6582636.733538e-08
1.375251.6581566.825804e-08
1.382351.6580496.918547e-08
1.38951.6579417.011769e-08
1.396671.6578327.105472e-08
1.403891.6577237.199660e-08
1.411141.6576137.294334e-08
1.418431.6575037.389497e-08
1.425761.6573927.485152e-08
1.433121.657287.581301e-08
1.440521.6571687.677946e-08
1.447961.6570567.775091e-08
1.455441.6569427.872737e-08
1.462961.6568287.970888e-08
1.470521.6567148.069546e-08
1.478111.6565988.168714e-08
1.485751.6564828.268393e-08
1.493421.6563668.368588e-08
1.501141.6562488.469300e-08
1.508891.656138.570532e-08
1.516691.6560118.672288e-08
1.524521.6558918.774569e-08
1.531.6558078.846100e-08
1.53241.6557719.119945e-08
1.540311.655651.002471e-07
1.548271.6555271.093415e-07
1.556271.6554051.184829e-07
1.56431.6552811.276715e-07
1.572381.6551561.369075e-07
1.580511.6550311.461913e-07
1.588671.6549041.555230e-07
1.596881.6547771.649029e-07
1.605131.6546491.743313e-07
1.613421.654521.838084e-07
1.621751.654391.933344e-07
1.630131.6542592.029097e-07
1.638551.6541272.125344e-07
1.647011.6539942.222088e-07
1.655521.653862.319332e-07
1.664071.6537252.417078e-07
1.672671.6535892.515329e-07
1.681311.6534522.614088e-07
1.689991.6533142.713356e-07
1.698721.6531752.813138e-07
1.70751.6530342.913435e-07
1.716321.6528933.014250e-07
1.725181.652753.115586e-07
1.734091.6526063.217445e-07
1.743051.6524613.319830e-07
1.752061.6523153.422745e-07
1.761111.6521683.526191e-07
1.77021.6520193.630171e-07
1.779351.6518693.734688e-07
1.788541.6517183.839745e-07
1.797781.6515653.945345e-07
1.807061.6514114.051490e-07
1.81641.6512564.158184e-07
1.825781.65114.265429e-07
1.835211.6509424.373228e-07
1.844691.6507824.481583e-07
1.854221.6506224.590499e-07
1.86381.6504594.699976e-07
1.873421.6502964.810020e-07
1.88311.6501314.920632e-07
1.892831.6499645.031815e-07
1.902611.6497965.143572e-07
1.912431.6496265.255907e-07
1.922311.6494555.368822e-07
1.932241.6492825.482320e-07
1.942221.6491075.596405e-07
1.952261.6489315.711079e-07
1.962341.6487535.826345e-07
1.971.6486185.913900e-07
1.972481.6485746.181291e-07
1.982671.6483927.281398e-07
1.992911.6482098.387188e-07
2.00321.6480259.498689e-07
2.013551.6478381.061593e-06
2.023951.647651.173895e-06
2.03441.647461.286776e-06
2.044911.6472671.400241e-06
2.055481.6470731.514291e-06
2.066091.6468781.628931e-06
2.076771.646681.744163e-06
2.087491.646481.859990e-06
2.098281.6462781.976416e-06
2.109111.6460742.093443e-06
2.120011.6458682.211074e-06
2.130961.645662.329313e-06
2.141971.645452.448163e-06
2.153031.6452382.567626e-06
2.164151.6450232.687707e-06
2.175331.6448062.808408e-06
2.186571.6445872.929733e-06
2.197861.6443663.051684e-06
2.209221.6441433.174265e-06
2.220631.6439173.297480e-06
2.23211.6436883.421330e-06
2.243631.6434583.545821e-06
2.255221.6432253.670955e-06
2.266871.6429893.796735e-06
2.278581.6427513.923164e-06
2.290351.642514.050247e-06
2.302181.6422674.177986e-06
2.314071.6420214.306385e-06
2.3251.6417944.424400e-06
2.326021.6417734.461210e-06
2.338041.6415214.893449e-06
2.350121.6412675.327921e-06
2.362251.6410115.764638e-06
2.374461.6407516.203610e-06
2.386721.6404896.644850e-06
2.399051.6402237.088369e-06
2.411441.6399557.534180e-06
2.42391.6396847.982292e-06
2.436421.639418.432720e-06
2.449011.6391338.885475e-06
2.461661.6388529.340568e-06
2.474371.6385699.798011e-06
2.487151.6382821.025782e-05
2.51.6379921.072000e-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
—