Optical constants

Refractive index of N-LASF31A (SCHOTT)

N-LASF31A: n,k 0.25–2.5 µm

Data
formula 2 + tabulated k
Range
0.25–2.5 µm
Temperature
293 K
Licence
CC0-1.0

Plot

Click the plot to set the calculator wavelength. Note: k data cover 334-2500 nm only; k = 0 elsewhere in the n range 250-2500 nm.

At one wavelength

Range 0.25–2.5 µm
Refractive index n
1.883
Extinction coefficient k
1.87982e-08
Permittivity ε1
3.54567
Permittivity ε2
7.07939e-08
Absorption coefficient α
0.00402017 cm⁻¹
Penetration depth δ = λ/(2πk)
4.97491e+09 nm
Abbe number Vd
40.76
Chromatic dispersion dn/dλ
-0.110638 µm⁻¹
Group index ng
1.94801
Group velocity dispersion
208.47 fs²/mm
Dispersion parameter D
-1137.31 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-LASF31A (SCHOTT): N-LASF31A
schott_n_lasf31a = ls.fetch_refractiveindex("specs", "SCHOTT-optical", "N-LASF31A", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(schott_n_lasf31a.range_nm)  # (250, 2500) nm
eps = schott_n_lasf31a.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=1.96485075λ2λ2−0.00982060155+0.475231259λ2λ2−0.0344713438+1.48360109λ2λ2−110.739863

Valid from 0.25 to 2.5 µm.

Coefficients as stored
CiValue
C10.0
C21.96485075
C30.00982060155
C40.475231259
C50.0344713438
C61.48360109
C7110.739863

Comments and conditions

Conditions

temperature
293 K

Properties

thermal dispersion
type: formula A, coefficients: 1.67e-06 8.9e-09 -8.73e-12 7.47e-07 7.46e-10 0.207
nd
1.883
Vd
40.76
glass code
883408.551
glass status
standard
density
value: 5510
thermal expansion
value: 6.74e-06, temperature range: 243 343; value: 7.72e-06, temperature range: 293 573
dPgF
-0.0085
resistance
acid: 2.3; 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 = 2.53e-06 K⁻¹ at 633 nm, dn/dT = 1.39e-06 K⁻¹ at 1310 nm, dn/dT = 1.30e-06 K⁻¹ at 1550 nm
Notes on the source data (kept exactly as published):
  • k data cover 334-2500 nm only; k = 0 elsewhere in the n range 250-2500 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 421 wavelengths, the same grid as the API and the library
N-LASF31A (SCHOTT), N-LASF31A: n and k versus wavelength
λ (µm)nk
0.252.0952340
0.2514472.0905190
0.2529022.0859490
0.2543662.0815150
0.2558382.0772120
0.2573192.0730340
0.2588082.0689750
0.2603062.0650290
0.2618122.0611920
0.2633282.0574590
0.2648522.0538260
0.2663842.0502890
0.2679262.0468430
0.2694772.0434850
0.2710362.0402120
0.2726052.037020
0.2741832.0339060
0.275772.0308680
0.2773662.0279030
0.2789712.0250070
0.2805862.0221790
0.2822092.0194160
0.2838432.0167160
0.2854862.0140760
0.2871382.0114960
0.28882.0089720
0.2904712.0065030
0.2921522.0040870
0.2938432.0017230
0.2955441.9994080
0.2972541.9971420
0.2989751.9949230
0.3007051.9927490
0.3024451.990620
0.3041961.9885330
0.3059561.9864870
0.3077271.9844820
0.3095081.9825170
0.3112991.9805890
0.3131011.9786990
0.3149131.9768450
0.3167361.9750250
0.3185691.973240
0.3204121.9714890
0.3222671.9697690
0.3241321.9680820
0.3260081.9664250
0.3278951.9647980
0.3297921.96320
0.3317011.961630
0.3336211.9600890
0.3341.9597895.439100e-06
0.3355521.9585755.105611e-06
0.3374941.9570874.688256e-06
0.3394471.9556254.268486e-06
0.3414121.9541883.846287e-06
0.3433881.9527763.421644e-06
0.3453751.9513882.994543e-06
0.3473741.9500232.564971e-06
0.3493841.9486822.132912e-06
0.351.9482772.000600e-06
0.3514061.9473631.899283e-06
0.353441.9460661.752770e-06
0.3554861.944791.605409e-06
0.3575431.9435351.457195e-06
0.3596121.9423011.308124e-06
0.3616941.9410871.158190e-06
0.3637871.9398931.007388e-06
0.3651.9392139.200100e-07
0.3658931.9387188.853263e-07
0.368011.9375618.030352e-07
0.371.9364977.257100e-07
0.370141.9364237.219557e-07
0.3722821.9353046.645272e-07
0.3744371.9342016.067664e-07
0.3766041.9331175.486713e-07
0.3787841.9320494.902400e-07
0.381.9314634.576300e-07
0.3809761.9309974.430719e-07
0.3831811.9299624.101766e-07
0.3853981.9289433.770909e-07
0.3876291.927943.438138e-07
0.3898721.9269523.103440e-07
0.391.9268963.084400e-07
0.3921291.9259792.897152e-07
0.3943981.9250212.697529e-07
0.3966811.9240772.496750e-07
0.3989771.9231472.294810e-07
0.41.9227392.204800e-07
0.4012861.9222312.130121e-07
0.4036081.9213291.995232e-07
0.4051.9207971.914400e-07
0.4059441.920441.879761e-07
0.4082941.9195651.793568e-07
0.4106571.9187021.706877e-07
0.4130331.9178521.619683e-07
0.4154241.9170141.531985e-07
0.4178281.9161881.443779e-07
0.421.9154571.364100e-07
0.4202461.9153751.359295e-07
0.4226791.9145731.311852e-07
0.4251251.9137821.264134e-07
0.4275851.9130031.216140e-07
0.430061.9122351.167868e-07
0.4325491.9114781.119317e-07
0.4350521.9107321.070485e-07
0.4361.9104531.052000e-07
0.437571.9099961.032310e-07
0.4401031.9092711.000554e-07
0.442651.9085569.686138e-08
0.4452121.907859.364890e-08
0.4477881.9071559.041784e-08
0.450381.9064698.716807e-08
0.4529871.9057938.389949e-08
0.4556081.9051268.061199e-08
0.4582451.9044687.730547e-08
0.461.9040377.510500e-08
0.4608971.9038197.421442e-08
0.4635651.9031797.156695e-08
0.4662481.9025476.890416e-08
0.4689461.9019256.622596e-08
0.471661.901316.353225e-08
0.474391.9007046.082296e-08
0.4771361.9001065.809798e-08
0.4798971.8995165.535723e-08
0.4826741.8989345.260063e-08
0.4854681.898364.982806e-08
0.4882781.8977934.703945e-08
0.4911041.8972344.423471e-08
0.4939461.8966824.141373e-08
0.4968051.8961373.857642e-08
0.499681.8955993.572269e-08
0.51.895543.540500e-08
0.5025721.8950693.440209e-08
0.5054811.8945453.326784e-08
0.5084061.8940283.212702e-08
0.5113481.8935183.097959e-08
0.5143081.8930152.982553e-08
0.5172851.8925182.866479e-08
0.5202781.8920272.749733e-08
0.5232891.8915422.632311e-08
0.5263181.8910642.514210e-08
0.5293641.8905922.395425e-08
0.5324281.8901252.275953e-08
0.5355091.8896652.155789e-08
0.5386091.889212.034930e-08
0.5417261.8887611.913371e-08
0.5448611.8883181.791109e-08
0.5461.8881591.746700e-08
0.5480151.887881.753147e-08
0.5511861.8874481.763296e-08
0.5543761.8870211.773504e-08
0.5575851.8865991.783771e-08
0.5608121.8861831.794098e-08
0.5640581.8857711.804484e-08
0.5673221.8853651.814931e-08
0.5706061.8849631.825438e-08
0.5739081.8845671.836006e-08
0.577231.8841751.846634e-08
0.581.8838541.855500e-08
0.580571.8837881.857325e-08
0.583931.8834061.868077e-08
0.587311.8830281.878892e-08
0.5907091.8826541.889769e-08
0.5941281.8822861.900709e-08
0.5975661.8819211.911712e-08
0.6010251.8815611.922779e-08
0.6045031.8812051.933910e-08
0.6080021.8808531.945106e-08
0.6115211.8805061.956366e-08
0.615061.8801621.967692e-08
0.618621.8798221.979083e-08
0.621.8796921.983500e-08
0.62221.8794871.978869e-08
0.6258011.8791551.971289e-08
0.6294231.8788271.963665e-08
0.6330661.8785031.955997e-08
0.636731.8781821.948284e-08
0.6404151.8778651.940527e-08
0.6441211.8775521.932725e-08
0.6478491.8772421.924878e-08
0.6515991.8769361.916985e-08
0.655371.8766331.909047e-08
0.6591631.8763331.901062e-08
0.661.8762681.899300e-08
0.6629781.8760371.891141e-08
0.6668151.8757441.880628e-08
0.6706741.8754551.870053e-08
0.6745561.8751681.859418e-08
0.678461.8748851.848721e-08
0.6823861.8746041.837962e-08
0.6863361.8743271.827141e-08
0.6903081.8740531.816257e-08
0.6943031.8737811.805310e-08
0.6983211.8735131.794300e-08
0.71.8734021.789700e-08
0.7023631.8732471.789054e-08
0.7064281.8729841.787943e-08
0.7105161.8727241.786826e-08
0.7146291.8724671.785702e-08
0.7187651.8722121.784571e-08
0.7229241.871961.783434e-08
0.7271081.8717111.782290e-08
0.7313171.8714641.781140e-08
0.7355491.8712191.779983e-08
0.7398061.8709771.778820e-08
0.7440881.8707381.777649e-08
0.7483941.8705011.776472e-08
0.7527261.8702661.775288e-08
0.7570821.8700331.774098e-08
0.7614641.8698031.772900e-08
0.7658711.8695751.771695e-08
0.7703031.869351.770484e-08
0.7747621.8691261.769265e-08
0.7792461.8689041.768040e-08
0.7837561.8686851.766807e-08
0.7882921.8684681.765567e-08
0.7928541.8682531.764320e-08
0.7974431.8680391.763066e-08
0.8020581.8678281.761804e-08
0.80671.8676191.760535e-08
0.8113691.8674111.759259e-08
0.8160641.8672051.757976e-08
0.8207881.8670021.756685e-08
0.8255381.86681.755386e-08
0.8303161.8665991.754080e-08
0.8351211.8664011.752767e-08
0.8399551.8662041.751446e-08
0.8448161.8660091.750117e-08
0.8497051.8658151.748781e-08
0.8546231.8656241.747436e-08
0.8595691.8654331.746084e-08
0.8645441.8652451.744725e-08
0.8695481.8650571.743357e-08
0.874581.8648721.741981e-08
0.8796421.8646881.740598e-08
0.8847331.8645051.739206e-08
0.8898531.8643231.737807e-08
0.8950031.8641431.736399e-08
0.9001831.8639651.734983e-08
0.9053931.8637881.733559e-08
0.9106331.8636121.732127e-08
0.9159041.8634371.730686e-08
0.9212041.8632641.729237e-08
0.9265361.8630911.727780e-08
0.9318981.862921.726314e-08
0.9372921.8627511.724840e-08
0.9427171.8625821.723357e-08
0.9481731.8624141.721866e-08
0.953661.8622481.720366e-08
0.959181.8620831.718858e-08
0.9647311.8619181.717340e-08
0.9703141.8617551.715814e-08
0.975931.8615931.714279e-08
0.9815781.8614321.712735e-08
0.9872591.8612711.711182e-08
0.9929731.8611121.709621e-08
0.998721.8609531.708050e-08
1.00451.8607961.706470e-08
1.010311.8606391.704881e-08
1.016161.8604831.703283e-08
1.022041.8603281.701675e-08
1.027961.8601741.700058e-08
1.033911.860021.698432e-08
1.039891.8598681.696797e-08
1.045911.8597161.695152e-08
1.051961.8595641.693497e-08
1.058051.8594141.691833e-08
1.061.8593661.691300e-08
1.064171.8592641.750440e-08
1.070331.8591141.837702e-08
1.076531.8589661.925470e-08
1.082761.8588172.013745e-08
1.089021.858672.102531e-08
1.095331.8585232.191832e-08
1.101671.8583762.281648e-08
1.108041.8582312.371985e-08
1.114461.8580852.462845e-08
1.120911.857942.554230e-08
1.127391.8577962.646145e-08
1.133921.8576512.738591e-08
1.140481.8575082.831572e-08
1.147081.8573642.925092e-08
1.153721.8572213.019152e-08
1.16041.8570793.113758e-08
1.167111.8569363.208910e-08
1.173871.8567943.304614e-08
1.180661.8566533.400871e-08
1.187491.8565113.497685e-08
1.194371.856373.595060e-08
1.201281.8562293.692998e-08
1.208231.8560883.791503e-08
1.215231.8559483.890578e-08
1.222261.8558073.990227e-08
1.229331.8556674.090452e-08
1.236451.8555274.191257e-08
1.24361.8553874.292646e-08
1.25081.8552474.394622e-08
1.258041.8551074.497187e-08
1.265321.8549674.600347e-08
1.272641.8548274.704103e-08
1.280011.8546874.808460e-08
1.287421.8545474.913421e-08
1.294871.8544075.018989e-08
1.302361.8542675.125169e-08
1.30991.8541275.231962e-08
1.317481.8539875.339374e-08
1.325111.8538465.447408e-08
1.332781.8537065.556067e-08
1.340491.8535655.665354e-08
1.348251.8534245.775275e-08
1.356051.8532835.885831e-08
1.36391.8531425.997027e-08
1.371791.8536.108867e-08
1.379731.8528596.221354e-08
1.387721.8527176.334492e-08
1.395751.8525746.448285e-08
1.403831.8524316.562737e-08
1.411951.8522886.677850e-08
1.420121.8521456.793631e-08
1.428341.8520016.910081e-08
1.436611.8518577.027205e-08
1.444921.8517127.145007e-08
1.453291.8515677.263491e-08
1.46171.8514217.382660e-08
1.470161.8512757.502519e-08
1.478671.8511297.623072e-08
1.487221.8509817.744323e-08
1.495831.8508347.866275e-08
1.504491.8506857.988934e-08
1.513191.8505368.112302e-08
1.521951.8503878.236384e-08
1.531.850258.350400e-08
1.530761.8502378.438257e-08
1.539621.8500869.460884e-08
1.548531.8499341.048943e-07
1.557491.8497821.152393e-07
1.566511.8496291.256442e-07
1.575571.8494751.361092e-07
1.584691.849321.466349e-07
1.593861.8491651.572215e-07
1.603091.8490091.678693e-07
1.612371.8488521.785788e-07
1.62171.8486941.893502e-07
1.631081.8485352.001840e-07
1.640521.8483752.110805e-07
1.650021.8482142.220400e-07
1.659571.8480522.330630e-07
1.669171.847892.441498e-07
1.678831.8477262.553007e-07
1.688551.8475612.665162e-07
1.698321.8473952.777966e-07
1.708151.8472282.891422e-07
1.718041.847063.005536e-07
1.727981.8468913.120310e-07
1.737981.846723.235748e-07
1.748041.8465483.351854e-07
1.758161.8463753.468632e-07
1.768331.8462013.586086e-07
1.778571.8460263.704220e-07
1.788861.8458493.823037e-07
1.799211.8456713.942543e-07
1.809631.8454914.062739e-07
1.82011.845314.183632e-07
1.830631.8451284.305224e-07
1.841231.8449444.427520e-07
1.851891.8447594.550524e-07
1.86261.8445724.674239e-07
1.873381.8443844.798671e-07
1.884231.8441944.923822e-07
1.895131.8440035.049698e-07
1.90611.843815.176303e-07
1.917131.8436155.303640e-07
1.928231.8434185.431715e-07
1.939391.843225.560530e-07
1.950611.843025.690091e-07
1.96191.8428185.820402e-07
1.971.8426735.913900e-07
1.973251.8426156.188412e-07
1.984671.8424097.151682e-07
1.996161.8422028.120527e-07
2.007711.8419939.094979e-07
2.019331.8417811.007507e-06
2.031021.8415681.106084e-06
2.042781.8413531.205231e-06
2.05461.8411361.304951e-06
2.066491.8409161.405249e-06
2.078451.8406951.506128e-06
2.090481.8404711.607590e-06
2.102581.8402451.709639e-06
2.114751.8400171.812279e-06
2.126991.8397861.915514e-06
2.13931.8395542.019345e-06
2.151681.8393182.123778e-06
2.164131.8390812.228815e-06
2.176661.8388412.334459e-06
2.189251.8385982.440716e-06
2.201921.8383532.547587e-06
2.214671.8381062.655077e-06
2.227481.8378562.763189e-06
2.240381.8376032.871926e-06
2.253341.8373472.981293e-06
2.266381.8370893.091293e-06
2.27951.8368283.201929e-06
2.292691.8365643.313206e-06
2.305961.8362973.425127e-06
2.319311.8360273.537696e-06
2.3251.8359123.585700e-06
2.332731.8357543.824610e-06
2.346231.8354794.241779e-06
2.359811.83524.661362e-06
2.373471.8349185.083374e-06
2.387211.8346335.507827e-06
2.401021.8343445.934738e-06
2.414921.8340536.364119e-06
2.428891.8337586.795986e-06
2.442951.8334597.230352e-06
2.457091.8331577.667231e-06
2.471311.8328528.106639e-06
2.485611.8325438.548591e-06
2.51.8322318.993100e-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
—