Optical constants

Refractive index of K-GFK68(M) (SUMITA)

K-GFK68(M): n,k 0.36–1.55 µm

Data
formula 3 + tabulated k
Range
0.36–1.55 µm
Temperature
293 K
Licence
CC0-1.0

Plot

Click the plot to set the calculator wavelength.

At one wavelength

Range 0.36–1.55 µm
Refractive index n
1.58998
Extinction coefficient k
9.36134e-09
Permittivity ε1
2.52803
Permittivity ε2
2.97687e-08
Absorption coefficient α
0.00200201 cm⁻¹
Penetration depth δ = λ/(2πk)
9.98996e+09 nm
Abbe number Vd
68.327
Chromatic dispersion dn/dλ
-0.0445104 µm⁻¹
Group index ng
1.61613
Group velocity dispersion
79.8803 fs²/mm
Dispersion parameter D
-435.789 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

# K-GFK68(M) (SUMITA): K-GFK68(M)
sumita_k_gfk68_m = ls.fetch_refractiveindex("specs", "SUMITA-optical", "K-GFK68(M)", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(sumita_k_gfk68_m.range_nm)  # (360, 1550) nm
eps = sumita_k_gfk68_m.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

Polynomial (formula 3), λ in µm
n2=2.4921178−0.0059252429⁢λ2.0+0.012541311⁢λ−2.0+0.00020379328⁢λ−4.0−3.7798198×10-6⁢λ−6.0+2.5829936×10-7⁢λ−8.0

Valid from 0.36 to 1.55 µm.

Coefficients as stored
CiValue
C12.4921178
C2-0.0059252429
C32.0
C40.012541311
C5-2.0
C60.00020379328
C7-4.0
C8-3.7798198e-06
C9-6.0
C102.5829936e-07
C11-8.0

Comments and conditions

Conditions

temperature
293 K

Properties

thermal dispersion
type: formula A, coefficients: -2.36e-05 2.85e-09 4.82e-11 4.01e-07 2.74e-10 0.183
nd
1.58998
Vd
68.3
glass code
592683
density
value: 4510
thermal expansion
value: 1.29e-05, temperature range: 243 343; value: 1.52e-05, temperature range: 293 573
dPgF
0.0179
resistance
acid: 1.0; climatic: 1.0

Thermo-optic coefficient

  • Schott thermal-dispersion model (reference temperature 293.0 K): dn/dT = -1.08e-05 K⁻¹ at 633 nm, dn/dT = -1.10e-05 K⁻¹ at 1310 nm, dn/dT = -1.10e-05 K⁻¹ at 1550 nm

References

Cite

SUMITA Zemax catalog 2017-02-02 (obtained from http://www.sumita-opt.co.jp); See also SUMITA optical glass data book; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)

Data

Computed on 416 wavelengths, the same grid as the API and the library
K-GFK68(M) (SUMITA), K-GFK68(M): n and k versus wavelength
λ (µm)nk
0.361.6122756.372900e-08
0.361321.6120045.922421e-08
0.3626441.6117345.470290e-08
0.3639731.6114675.016503e-08
0.3653081.6112024.561052e-08
0.3666471.610944.103931e-08
0.3679911.6106793.645135e-08
0.369341.6104213.184657e-08
0.371.6102962.959200e-08
0.3706931.6101652.859113e-08
0.3720521.6099112.662981e-08
0.3734161.6096592.466130e-08
0.3747851.609412.268558e-08
0.3761591.6091622.070261e-08
0.3775371.6089171.871238e-08
0.3789211.6086731.671484e-08
0.381.6084861.515800e-08
0.380311.6084321.497694e-08
0.3817041.6081921.416372e-08
0.3831041.6079551.334752e-08
0.3845081.607721.252833e-08
0.3859171.6074861.170614e-08
0.3873321.6072551.088093e-08
0.3887521.6070251.005270e-08
0.391.6068269.324600e-09
0.3901771.6067979.328827e-09
0.3916071.6065729.363010e-09
0.3930431.6063489.397318e-09
0.3944831.6061269.431751e-09
0.3959291.6059059.466311e-09
0.3973811.6056879.500998e-09
0.3988371.605479.535812e-09
0.41.6052999.563600e-09
0.4002991.6052559.570759e-09
0.4017671.6050429.605858e-09
0.4032391.6048319.641085e-09
0.4047171.6046219.676442e-09
0.4062011.6044139.711928e-09
0.407691.6042079.747545e-09
0.4091841.6040029.783292e-09
0.4106841.6037999.819169e-09
0.412191.6035989.855179e-09
0.4137011.6033989.891320e-09
0.4152171.60329.927594e-09
0.4167391.6030049.964001e-09
0.4182671.6028091.000054e-08
0.41981.6026151.003722e-08
0.421.602591.004200e-08
0.4213391.6024241.007400e-08
0.4228831.6022331.011091e-08
0.4244331.6020451.014796e-08
0.4259891.6018581.018514e-08
0.4275511.6016721.022246e-08
0.4291181.6014881.025992e-08
0.4306911.6013051.029751e-08
0.432271.6011241.033525e-08
0.4338541.6009441.037312e-08
0.4354451.6007651.041113e-08
0.4370411.6005881.044927e-08
0.4386431.6004131.048756e-08
0.441.6002661.052000e-08
0.4402511.6002391.052599e-08
0.4418641.6000661.056456e-08
0.4434841.5998941.060327e-08
0.445111.5997241.064212e-08
0.4467411.5995561.068112e-08
0.4483791.5993881.072026e-08
0.4500231.5992221.075954e-08
0.4516721.5990571.079896e-08
0.4533281.5988941.083853e-08
0.454991.5987321.087825e-08
0.4566571.5985711.091811e-08
0.4583311.5984111.095812e-08
0.461.5982541.099800e-08
0.4600111.5982521.099827e-08
0.4616981.5980951.103857e-08
0.463391.5979391.107902e-08
0.4650891.5977851.111962e-08
0.4667931.5976311.116036e-08
0.4685051.5974791.120126e-08
0.4702221.5973271.124230e-08
0.4719461.5971771.128350e-08
0.4736751.5970281.132484e-08
0.4754121.5968811.136634e-08
0.4771541.5967341.140799e-08
0.4789041.5965891.144979e-08
0.481.5964981.147600e-08
0.4806591.5964441.149178e-08
0.4824211.5963011.153398e-08
0.4841891.5961591.157633e-08
0.4859641.5960181.161884e-08
0.4877461.5958781.166151e-08
0.4895331.5957391.170433e-08
0.4913281.5956011.174730e-08
0.4931291.5954651.179044e-08
0.4949361.5953291.183373e-08
0.4967511.5951941.187718e-08
0.4985721.595061.192079e-08
0.51.5949571.195500e-08
0.5003991.5949281.192951e-08
0.5022331.5947961.181238e-08
0.5040741.5946651.169483e-08
0.5059221.5945361.157684e-08
0.5077771.5944071.145843e-08
0.5096381.5942791.133957e-08
0.5115061.5941531.122028e-08
0.5133811.5940271.110056e-08
0.5152631.5939021.098040e-08
0.5171521.5937781.085979e-08
0.5190471.5936551.073874e-08
0.520951.5935331.061725e-08
0.522861.5934121.049532e-08
0.5247761.5932911.037294e-08
0.52671.5931721.025010e-08
0.5286311.5930531.012682e-08
0.5305681.5929361.000309e-08
0.5325131.5928199.878902e-09
0.5344651.5927039.754260e-09
0.5364241.5925889.629160e-09
0.5383911.5924749.503603e-09
0.5403641.5923619.377585e-09
0.5423451.5922489.251105e-09
0.5443331.5921369.124161e-09
0.5463281.5920268.996753e-09
0.5483311.5919158.868877e-09
0.551.5918258.762300e-09
0.5503411.5918068.767731e-09
0.5523581.5916988.799871e-09
0.5543831.591598.832130e-09
0.5564151.5914838.864506e-09
0.5584551.5913778.897001e-09
0.5605021.5912728.929615e-09
0.5625561.5911678.962348e-09
0.5646191.5910638.995202e-09
0.5666881.590969.028176e-09
0.5687651.5908589.061271e-09
0.570851.5907569.094487e-09
0.5729431.5906559.127825e-09
0.5750431.5905559.161285e-09
0.5771511.5904569.194868e-09
0.5792671.5903579.228574e-09
0.581391.5902599.262404e-09
0.5835211.5901629.296357e-09
0.585661.5900659.330435e-09
0.5878071.5899699.364638e-09
0.5899611.5898749.398966e-09
0.5921241.5897799.433420e-09
0.5942951.5896859.468001e-09
0.5964731.5895929.502708e-09
0.5986591.5894999.537542e-09
0.61.5894439.558900e-09
0.6008541.5894079.572496e-09
0.6030561.5893169.607564e-09
0.6052671.5892259.642761e-09
0.6074861.5891359.678087e-09
0.6097121.5890469.713542e-09
0.6119471.5889579.749127e-09
0.6141911.5888689.784843e-09
0.6164421.5887819.820689e-09
0.6187021.5886949.856667e-09
0.620971.5886079.892777e-09
0.6232461.5885219.929019e-09
0.625531.5884369.965394e-09
0.6278231.5883521.000190e-08
0.6301251.5882671.003854e-08
0.6324341.5881841.007532e-08
0.6347531.5881011.011223e-08
0.6370791.5880191.014928e-08
0.6394151.5879371.018646e-08
0.6417591.5878551.022378e-08
0.6441111.5877751.026124e-08
0.6464721.5876941.029883e-08
0.6488421.5876151.033656e-08
0.651.5875761.035500e-08
0.651221.5875361.037445e-08
0.6536071.5874571.041250e-08
0.6560031.5873791.045069e-08
0.6584081.5873011.048902e-08
0.6608211.5872241.052749e-08
0.6632441.5871471.056610e-08
0.6656751.5870711.060486e-08
0.6681151.5869961.064375e-08
0.6705641.5869211.068279e-08
0.6730221.5868461.072197e-08
0.6754891.5867721.076130e-08
0.6779651.5866981.080077e-08
0.680451.5866251.084038e-08
0.6829451.5865521.088014e-08
0.6854481.586481.092004e-08
0.6879611.5864081.096009e-08
0.6904821.5863371.100029e-08
0.6930131.5862661.104063e-08
0.6955541.5861951.108113e-08
0.6981031.5861251.112177e-08
0.71.5860741.115200e-08
0.7006621.5860561.116255e-08
0.7032311.5859871.120347e-08
0.7058091.5859181.124453e-08
0.7083961.585851.128574e-08
0.7109921.5857821.132711e-08
0.7135991.5857141.136863e-08
0.7162141.5856471.141030e-08
0.718841.5855811.145212e-08
0.7214751.5855141.149409e-08
0.7241191.5854491.153622e-08
0.7267741.5853831.157851e-08
0.7294381.5853181.162095e-08
0.7321121.5852531.166354e-08
0.7347951.5851891.170629e-08
0.7374891.5851251.174920e-08
0.7401921.5850621.179226e-08
0.7429051.5849991.183548e-08
0.7456291.5849361.187886e-08
0.7483621.5848731.192240e-08
0.7511051.5848111.196610e-08
0.7538581.584751.200996e-08
0.7566221.5846881.205398e-08
0.7593951.5846271.209816e-08
0.7621791.5845671.214251e-08
0.7649731.5845061.218701e-08
0.7677771.5844461.223168e-08
0.7705911.5843871.227652e-08
0.7734161.5843271.232151e-08
0.7762511.5842681.236668e-08
0.7790961.584211.241200e-08
0.7819521.5841521.245750e-08
0.7848181.5840941.250316e-08
0.7876951.5840361.254899e-08
0.7905831.5839781.259498e-08
0.7934811.5839211.264115e-08
0.7963891.5838651.268748e-08
0.7993091.5838081.273398e-08
0.81.5837951.274500e-08
0.8022381.5837521.321859e-08
0.8051791.5836961.384075e-08
0.8081311.5836411.446520e-08
0.8110931.5835851.509193e-08
0.8140661.583531.572095e-08
0.817051.5834751.635229e-08
0.8200451.5834211.698594e-08
0.8230511.5833671.762191e-08
0.8260681.5833131.826021e-08
0.8290961.5832591.890085e-08
0.8321351.5832061.954384e-08
0.8351861.5831532.018919e-08
0.8382471.58312.083690e-08
0.841321.5830472.148699e-08
0.8444041.5829952.213946e-08
0.8474991.5829432.279432e-08
0.8506061.5828912.345158e-08
0.8537241.582842.411125e-08
0.8568531.5827882.477334e-08
0.8599941.5827372.543786e-08
0.8631461.5826862.610481e-08
0.866311.5826362.677421e-08
0.8694861.5825852.744606e-08
0.8726731.5825352.812037e-08
0.8758721.5824852.879716e-08
0.8790821.5824352.947642e-08
0.8823051.5823863.015818e-08
0.8855391.5823363.084243e-08
0.8887851.5822873.152920e-08
0.8920431.5822383.221848e-08
0.8953131.582193.291028e-08
0.8985951.5821413.360463e-08
0.9018891.5820933.430152e-08
0.9051951.5820453.500096e-08
0.9085131.5819973.570296e-08
0.9118431.5819493.640754e-08
0.9151861.5819023.711471e-08
0.918541.5818543.782446e-08
0.9219071.5818073.853682e-08
0.9252871.581763.925179e-08
0.9286781.5817143.996938e-08
0.9320831.5816674.068960e-08
0.9354991.5816214.141245e-08
0.9389281.5815744.213796e-08
0.942371.5815284.286613e-08
0.9458241.5814824.359697e-08
0.9492911.5814364.433049e-08
0.9527711.5813914.506669e-08
0.9562641.5813454.580559e-08
0.9597691.58134.654721e-08
0.9632871.5812554.729154e-08
0.9668181.581214.803860e-08
0.9703621.5811654.878839e-08
0.9739191.581124.954094e-08
0.9774891.5810765.029625e-08
0.9810721.5810325.105432e-08
0.9846681.5809875.181517e-08
0.9882781.5809435.257881e-08
0.9919011.5808995.334525e-08
0.9955361.5808555.411450e-08
0.9991861.5808115.488657e-08
1.002851.5807685.566147e-08
1.006521.5807245.643921e-08
1.010211.5806815.721980e-08
1.013921.5806385.800326e-08
1.017631.5805955.878958e-08
1.021361.5805515.957879e-08
1.025111.5805096.037089e-08
1.028871.5804666.116589e-08
1.032641.5804236.196381e-08
1.036421.580386.276465e-08
1.040221.5803386.356843e-08
1.044031.5802956.437515e-08
1.047861.5802536.518483e-08
1.05171.5802116.599748e-08
1.055561.5801696.681311e-08
1.059431.5801276.763173e-08
1.061.5801216.775300e-08
1.063311.5800856.832746e-08
1.067211.5800436.900386e-08
1.071121.5800016.968273e-08
1.075051.5799597.036410e-08
1.078991.5799187.104797e-08
1.082941.5798767.173434e-08
1.086911.5798357.242322e-08
1.09091.5797937.311464e-08
1.094891.5797527.380858e-08
1.098911.5797117.450507e-08
1.102941.5796697.520412e-08
1.106981.5796287.590572e-08
1.111041.5795877.660990e-08
1.115111.5795467.731666e-08
1.11921.5795057.802601e-08
1.12331.5794647.873796e-08
1.127421.5794237.945252e-08
1.131551.5793828.016970e-08
1.13571.5793428.088951e-08
1.139861.5793018.161196e-08
1.144041.579268.233705e-08
1.148231.5792198.306480e-08
1.152441.5791798.379522e-08
1.156671.5791388.452832e-08
1.160911.5790978.526411e-08
1.165161.5790578.600259e-08
1.169431.5790168.674378e-08
1.173721.5789768.748769e-08
1.178021.5789358.823432e-08
1.182341.5788958.898369e-08
1.186671.5788548.973581e-08
1.191021.5788149.049068e-08
1.195391.5787749.124832e-08
1.199771.5787339.200874e-08
1.204171.5786939.277194e-08
1.208581.5786529.353795e-08
1.213011.5786129.430676e-08
1.217461.5785729.507839e-08
1.221921.5785319.585284e-08
1.22641.5784919.663014e-08
1.23091.578459.741029e-08
1.235411.578419.819329e-08
1.239941.578379.897917e-08
1.244481.5783299.976792e-08
1.249041.5782891.005596e-07
1.253621.5782481.013541e-07
1.258221.5782081.021516e-07
1.262831.5781671.029520e-07
1.267461.5781271.037553e-07
1.272111.5780861.045616e-07
1.276771.5780461.053708e-07
1.281451.5780051.061830e-07
1.286151.5779641.069981e-07
1.290861.5779241.078163e-07
1.295591.5778831.086374e-07
1.300341.5778421.094616e-07
1.305111.5778021.102888e-07
1.309891.5777611.111190e-07
1.314691.577721.119522e-07
1.319511.5776791.127885e-07
1.324351.5776381.136279e-07
1.32921.5775971.144704e-07
1.334081.5775561.153159e-07
1.338971.5775151.161646e-07
1.343881.5774741.170163e-07
1.34881.5774321.178712e-07
1.353751.5773911.187292e-07
1.358711.577351.195903e-07
1.363691.5773081.204546e-07
1.368691.5772671.213221e-07
1.37371.5772251.221928e-07
1.378741.5771831.230666e-07
1.383791.5771421.239437e-07
1.388871.57711.248239e-07
1.393961.5770581.257074e-07
1.399071.5770161.265942e-07
1.40421.5769741.274842e-07
1.409341.5769321.283774e-07
1.414511.576891.292739e-07
1.419691.5768471.301737e-07
1.42491.5768051.310768e-07
1.430121.5767621.319832e-07
1.435361.576721.328930e-07
1.440621.5766771.338061e-07
1.445911.5766341.347225e-07
1.451211.5765911.356422e-07
1.456521.5765481.365654e-07
1.461861.5765051.374919e-07
1.467221.5764621.384219e-07
1.47261.5764181.393552e-07
1.4781.5763751.402920e-07
1.483421.5763311.412321e-07
1.488851.5762871.421758e-07
1.494311.5762441.431229e-07
1.499791.57621.440735e-07
1.51.5761981.441100e-07
1.505291.5761551.456430e-07
1.51081.5761111.472430e-07
1.516341.5760671.488488e-07
1.52191.5760221.504605e-07
1.527481.5759781.520781e-07
1.533081.5759331.537016e-07
1.53871.5758881.553311e-07
1.544341.5758431.569666e-07
1.551.5757971.586080e-07

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
—