Optical constants

Refractive index of IRG 25 (SCHOTT)

IRG 25: n,k 0.85–12 µm

Data: formula 2 + tabulated k
Range: 0.85–12 µm
Temperature: 293 K
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength. Note: k data cover 1000-15500 nm only; k = 0 elsewhere in the n range 850-12000 nm.

At one wavelength

Refractive index n: 2.6263
Extinction coefficient k: 7.95292e-07

Permittivity ε₁: 6.89745
Permittivity ε₂: 4.17735e-06

Absorption coefficient α: 0.0313289 cm⁻¹
Penetration depth δ = λ/(2πk): 6.38387e+08 nm

Abbe number V_d: —
Chromatic dispersion dn/dλ: -0.00698703 µm⁻¹

Group index n_g: 2.64859
Group velocity dispersion: 311.148 fs²/mm

Dispersion parameter D: -57.5952 ps/(nm·km)
Photon energy: 0.388665 eV

ε = (n + ik)², α = 4πk/λ, n_g = 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

# IRG 25 (SCHOTT): IRG 25
schott_irg25 = ls.fetch_refractiveindex("specs", "SCHOTT-infrared", "IRG25", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(schott_irg25.range_nm)  # (850, 12000) nm
eps = schott_irg25.eps([3190])  # complex permittivity

Downloads the original record once (pinned to the imported snapshot) and caches it.

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_14d70234020b/lightsmith"
schott_irg25 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(schott_irg25.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (schott-irg25/schott).

# ... load schott_irg25 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=schott_irg25)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=850, stop_nm=1000, num=81),
)
res = ls.solve(sim)  # exact Mie for a sphere
print(res.q_ext)     # extinction efficiency at each wavelength

Same spec runs with DDA, FDTD, BEM or T-matrix: ls.compare(sim, ["mie", "dda"]).

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_14d70234020b/lightsmith?model=drude_lorentz"
schott_irg25_dl = ls.DrudeLorentz.model_validate(json.load(urllib.request.urlopen(url)))

A dispersive Drude–Lorentz model for time-domain solvers.

Materials guide Open a sphere of it in Studio Quick start Ask the community

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

n^{2} - 1 = 2.7574 + \frac{3.099 λ^{2}}{λ^{2} - 0.1596} + \frac{1.666 λ^{2}}{λ^{2} - 2045.5}

Valid from 0.85 to 12.0 µm.

Coefficients as stored

C_i	Value
C1	2.7574
C2	3.099
C3	0.1596
C4	1.666
C5	2045.5

Comments and conditions

Conditions

temperature: 293 K

Properties

thermal dispersion: type: formula A, coefficients: 1.80e-05 0 0 2.10e-07 0 1.67e-03
density: value: 4660
thermal expansion: value: 14.0e-06, temperature range: 293 373
specific heat: value: 330
thermal conductivity: value: 0.25
transformation temperature: value: 558
hardness: type: Knoop, value: 1.13e9
fracture toughness: value: 0.438e6
youngs modulus: value: 22.1e9

Thermo-optic coefficient

Schott thermal-dispersion model (reference temperature 293.0 K): dn/dT = 2.09e-05 K⁻¹ at 1310 nm, dn/dT = 2.07e-05 K⁻¹ at 1550 nm

Notes on the source data (kept exactly as published):

k data cover 1000-15500 nm only; k = 0 elsewhere in the n range 850-12000 nm

References

SCHOTT Infrared Chalcogenide Glasses - IRG 25 Product flyer (Version April 2017)

Cite

SCHOTT Infrared Chalcogenide Glasses - IRG 25 Product flyer (Version April 2017); Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)

Data

Computed on 422 wavelengths, the same grid as the API and the library

CSV comma separated TXT tab separated YAML n, k Full database record original YAML All quantities CSV JSON metadata

IRG 25 (SCHOTT), IRG 25: n and k versus wavelength
λ (µm)	n	k
0.85	2.781093	0
0.855659	2.778427	0
0.861355	2.775813	0
0.867089	2.77325	0
0.872862	2.770737	0
0.878672	2.768272	0
0.884522	2.765853	0
0.89041	2.763481	0
0.896338	2.761154	0
0.902305	2.75887	0
0.908312	2.75663	0
0.914359	2.75443	0
0.920446	2.752272	0
0.926573	2.750154	0
0.932742	2.748074	0
0.938951	2.746033	0
0.945202	2.744028	0
0.951495	2.74206	0
0.957829	2.740128	0
0.964205	2.73823	0
0.970624	2.736366	0
0.977086	2.734536	0
0.983591	2.732738	0
0.990139	2.730971	0
0.99673	2.729236	0
1	2.728391	1.618100e-06
1.00337	2.727531	1.610740e-06
1.01005	2.725856	1.596132e-06
1.01677	2.72421	1.581427e-06
1.02354	2.722592	1.566624e-06
1.03035	2.721003	1.551723e-06
1.03721	2.719441	1.536722e-06
1.04412	2.717905	1.521621e-06
1.05107	2.716396	1.506420e-06
1.05806	2.714913	1.491118e-06
1.06511	2.713454	1.475714e-06
1.0722	2.71202	1.460207e-06
1.07934	2.710611	1.444597e-06
1.08652	2.709225	1.428883e-06
1.09376	2.707862	1.413065e-06
1.10104	2.706522	1.397141e-06
1.10837	2.705204	1.381112e-06
1.11574	2.703908	1.364975e-06
1.12317	2.702633	1.348731e-06
1.13065	2.70138	1.332379e-06
1.13818	2.700146	1.315918e-06
1.14575	2.698933	1.299348e-06
1.15338	2.69774	1.282667e-06
1.16106	2.696566	1.265875e-06
1.16879	2.695412	1.248971e-06
1.17657	2.694275	1.231955e-06
1.1844	2.693158	1.214826e-06
1.19229	2.692058	1.197582e-06
1.20022	2.690975	1.180224e-06
1.20822	2.68991	1.162750e-06
1.21626	2.688862	1.145160e-06
1.22436	2.687831	1.127453e-06
1.23251	2.686816	1.109628e-06
1.24071	2.685817	1.091684e-06
1.24897	2.684834	1.073621e-06
1.25729	2.683866	1.055437e-06
1.26566	2.682913	1.037133e-06
1.27408	2.681975	1.018706e-06
1.28256	2.681052	1.000157e-06
1.2911	2.680143	9.814846e-07
1.2997	2.679249	9.626877e-07
1.30835	2.678368	9.437657e-07
1.31706	2.677501	9.247177e-07
1.32583	2.676647	9.055429e-07
1.33465	2.675806	8.862405e-07
1.34354	2.674978	8.668095e-07
1.35248	2.674163	8.472492e-07
1.36149	2.67336	8.275587e-07
1.37055	2.672569	8.077371e-07
1.37967	2.671791	7.877836e-07
1.38886	2.671024	7.676972e-07
1.3981	2.670269	7.474771e-07
1.40741	2.669525	7.271224e-07
1.41678	2.668792	7.066322e-07
1.42621	2.668071	6.860055e-07
1.43571	2.66736	6.652416e-07
1.44527	2.66666	6.443394e-07
1.45489	2.66597	6.232981e-07
1.46457	2.66529	6.021167e-07
1.47432	2.664621	5.807943e-07
1.48414	2.663962	5.593299e-07
1.49402	2.663312	5.377227e-07
1.5	2.662925	5.246400e-07
1.50396	2.662672	5.253689e-07
1.51398	2.662041	5.272099e-07
1.52405	2.66142	5.290632e-07
1.5342	2.660807	5.309288e-07
1.54441	2.660204	5.328069e-07
1.5547	2.65961	5.346975e-07
1.56505	2.659024	5.366006e-07
1.57546	2.658446	5.385164e-07
1.58595	2.657877	5.404450e-07
1.59651	2.657317	5.423864e-07
1.60714	2.656764	5.443407e-07
1.61784	2.65622	5.463081e-07
1.62861	2.655683	5.482885e-07
1.63945	2.655154	5.502822e-07
1.65036	2.654632	5.522890e-07
1.66135	2.654118	5.543093e-07
1.67241	2.653612	5.563430e-07
1.68355	2.653112	5.583903e-07
1.69475	2.65262	5.604511e-07
1.70604	2.652135	5.625257e-07
1.71739	2.651656	5.646141e-07
1.72883	2.651185	5.667164e-07
1.74033	2.65072	5.688328e-07
1.75192	2.650261	5.709631e-07
1.76358	2.649809	5.731077e-07
1.77532	2.649363	5.752666e-07
1.78714	2.648924	5.774398e-07
1.79904	2.648491	5.796275e-07
1.81102	2.648064	5.818297e-07
1.82307	2.647642	5.840467e-07
1.83521	2.647227	5.862783e-07
1.84743	2.646817	5.885249e-07
1.85973	2.646413	5.907864e-07
1.87211	2.646015	5.930629e-07
1.88457	2.645622	5.953546e-07
1.89712	2.645235	5.976616e-07
1.90974	2.644852	5.999839e-07
1.92246	2.644475	6.023216e-07
1.93526	2.644104	6.046750e-07
1.94814	2.643737	6.070440e-07
1.96111	2.643375	6.094287e-07
1.97416	2.643018	6.118294e-07
1.98731	2.642666	6.142460e-07
2	2.642333	6.165800e-07
2.00054	2.642319	6.167234e-07
2.01386	2.641977	6.202785e-07
2.02726	2.641639	6.238572e-07
2.04076	2.641305	6.274598e-07
2.05434	2.640976	6.310864e-07
2.06802	2.640652	6.347371e-07
2.08179	2.640332	6.384122e-07
2.09565	2.640016	6.421117e-07
2.1096	2.639704	6.458358e-07
2.12364	2.639396	6.495847e-07
2.13778	2.639093	6.533586e-07
2.15201	2.638793	6.571576e-07
2.16634	2.638498	6.609819e-07
2.18076	2.638206	6.648316e-07
2.19528	2.637918	6.687070e-07
2.20989	2.637634	6.726082e-07
2.2246	2.637353	6.765353e-07
2.23941	2.637076	6.804886e-07
2.25432	2.636803	6.844682e-07
2.26933	2.636533	6.884743e-07
2.28443	2.636267	6.925071e-07
2.29964	2.636004	6.965667e-07
2.31495	2.635745	7.006533e-07
2.33036	2.635488	7.047672e-07
2.34588	2.635236	7.089084e-07
2.36149	2.634986	7.130772e-07
2.37721	2.634739	7.172738e-07
2.39304	2.634496	7.214982e-07
2.40897	2.634255	7.257509e-07
2.42501	2.634018	7.300318e-07
2.44115	2.633783	7.343412e-07
2.4574	2.633552	7.386793e-07
2.47376	2.633323	7.430463e-07
2.49023	2.633097	7.474424e-07
2.5	2.632965	7.500500e-07
2.50681	2.632874	7.514186e-07
2.5235	2.632653	7.547726e-07
2.5403	2.632435	7.581490e-07
2.55721	2.63222	7.615478e-07
2.57423	2.632008	7.649692e-07
2.59137	2.631798	7.684135e-07
2.60862	2.63159	7.718806e-07
2.62599	2.631385	7.753709e-07
2.64347	2.631183	7.788844e-07
2.66107	2.630983	7.824213e-07
2.67878	2.630785	7.859817e-07
2.69662	2.630589	7.895658e-07
2.71457	2.630396	7.931738e-07
2.73264	2.630205	7.968058e-07
2.75083	2.630016	8.004620e-07
2.76914	2.629829	8.041425e-07
2.78758	2.629645	8.078475e-07
2.80614	2.629462	8.115772e-07
2.82482	2.629282	8.153317e-07
2.84362	2.629104	8.191112e-07
2.86255	2.628927	8.229159e-07
2.88161	2.628753	8.267459e-07
2.90079	2.62858	8.306014e-07
2.9201	2.628409	8.344825e-07
2.93954	2.628241	8.383896e-07
2.95911	2.628074	8.423226e-07
2.97881	2.627908	8.462818e-07
2.99864	2.627745	8.502673e-07
3	2.627734	8.505400e-07
3.01861	2.627583	8.451298e-07
3.0387	2.627423	8.392864e-07
3.05893	2.627265	8.334042e-07
3.07929	2.627108	8.274827e-07
3.09979	2.626953	8.215219e-07
3.12043	2.626799	8.155214e-07
3.1412	2.626647	8.094809e-07
3.16212	2.626496	8.034002e-07
3.18317	2.626347	7.972790e-07
3.20436	2.6262	7.911171e-07
3.22569	2.626054	7.849141e-07
3.24716	2.625909	7.786699e-07
3.26878	2.625765	7.723841e-07
3.29054	2.625623	7.660564e-07
3.31245	2.625482	7.596867e-07
3.3345	2.625343	7.532745e-07
3.3567	2.625205	7.468196e-07
3.37904	2.625068	7.403218e-07
3.40154	2.624932	7.337807e-07
3.42418	2.624797	7.271960e-07
3.44698	2.624664	7.205675e-07
3.46993	2.624532	7.138949e-07
3.49303	2.6244	7.071779e-07
3.5	2.624361	7.051500e-07
3.51628	2.62427	7.031287e-07
3.53969	2.624141	7.002223e-07
3.56325	2.624013	6.972965e-07
3.58697	2.623886	6.943513e-07
3.61085	2.62376	6.913864e-07
3.63489	2.623635	6.884018e-07
3.65909	2.623511	6.853974e-07
3.68345	2.623388	6.823729e-07
3.70797	2.623266	6.793283e-07
3.73266	2.623144	6.762635e-07
3.7575	2.623024	6.731782e-07
3.78252	2.622904	6.700724e-07
3.8077	2.622785	6.669459e-07
3.83305	2.622667	6.637987e-07
3.85857	2.622549	6.606304e-07
3.88425	2.622433	6.574411e-07
3.91011	2.622317	6.542305e-07
3.93614	2.622202	6.509986e-07
3.96235	2.622087	6.477451e-07
3.98872	2.621973	6.444700e-07
4	2.621925	6.430700e-07
4.01528	2.62186	6.726553e-07
4.04201	2.621747	7.244180e-07
4.06892	2.621635	7.765253e-07
4.096	2.621524	8.289794e-07
4.12327	2.621413	8.817828e-07
4.15072	2.621302	9.349376e-07
4.17835	2.621192	9.884464e-07
4.20617	2.621083	1.042311e-06
4.23417	2.620974	1.096535e-06
4.26236	2.620865	1.151119e-06
4.29074	2.620757	1.206067e-06
4.3193	2.62065	1.261381e-06
4.34805	2.620542	1.317063e-06
4.377	2.620436	1.373116e-06
4.40614	2.620329	1.429541e-06
4.43547	2.620223	1.486343e-06
4.465	2.620117	1.543522e-06
4.49472	2.620011	1.601082e-06
4.5	2.619993	1.611300e-06
4.52465	2.619906	1.620128e-06
4.55477	2.619801	1.630918e-06
4.58509	2.619696	1.641779e-06
4.61561	2.619591	1.652713e-06
4.64634	2.619487	1.663719e-06
4.67727	2.619382	1.674799e-06
4.70841	2.619278	1.685952e-06
4.73975	2.619174	1.697180e-06
4.77131	2.61907	1.708483e-06
4.80307	2.618966	1.719860e-06
4.83505	2.618863	1.731314e-06
4.86723	2.618759	1.742844e-06
4.89964	2.618655	1.754450e-06
4.93226	2.618552	1.766134e-06
4.96509	2.618448	1.777895e-06
4.99814	2.618344	1.789735e-06
5	2.618339	1.790400e-06
5.03142	2.618241	1.711102e-06
5.06491	2.618137	1.626559e-06
5.09863	2.618033	1.541453e-06
5.13257	2.617929	1.455782e-06
5.16674	2.617825	1.369539e-06
5.20114	2.617721	1.282723e-06
5.23576	2.617617	1.195328e-06
5.27062	2.617512	1.107352e-06
5.30571	2.617408	1.018790e-06
5.34103	2.617303	9.296387e-07
5.37658	2.617197	8.398938e-07
5.41238	2.617092	7.495513e-07
5.44841	2.616986	6.586075e-07
5.48468	2.61688	5.670582e-07
5.5	2.616836	5.283900e-07
5.52119	2.616774	5.263335e-07
5.55795	2.616668	5.227667e-07
5.59495	2.616561	5.191762e-07
5.6322	2.616453	5.155617e-07
5.66969	2.616345	5.119233e-07
5.70743	2.616237	5.082605e-07
5.74543	2.616129	5.045735e-07
5.78368	2.61602	5.008618e-07
5.82218	2.61591	4.971255e-07
5.86094	2.6158	4.933642e-07
5.89996	2.61569	4.895780e-07
5.93924	2.615579	4.857665e-07
5.97878	2.615467	4.819297e-07
6	2.615407	4.798700e-07
6.01858	2.615355	4.832978e-07
6.05864	2.615242	4.906910e-07
6.09898	2.615128	4.981334e-07
6.13958	2.615014	5.056253e-07
6.18045	2.6149	5.131671e-07
6.2216	2.614784	5.207591e-07
6.26302	2.614668	5.284016e-07
6.30471	2.614551	5.360950e-07
6.34668	2.614433	5.438397e-07
6.38893	2.614315	5.516359e-07
6.43147	2.614196	5.594840e-07
6.47428	2.614076	5.673843e-07
6.5	2.614003	5.721300e-07
6.51738	2.613955	5.697480e-07
6.56077	2.613833	5.638022e-07
6.60445	2.61371	5.578168e-07
6.64841	2.613586	5.517915e-07
6.69267	2.613462	5.457261e-07
6.73723	2.613336	5.396204e-07
6.78208	2.61321	5.334740e-07
6.82723	2.613082	5.272867e-07
6.87268	2.612954	5.210582e-07
6.91843	2.612824	5.147882e-07
6.96449	2.612693	5.084765e-07
7	2.612592	5.036100e-07
7.01085	2.612561	5.096303e-07
7.05753	2.612428	5.355206e-07
7.10451	2.612294	5.615832e-07
7.15181	2.612159	5.878194e-07
7.19942	2.612022	6.142302e-07
7.24734	2.611884	6.408169e-07
7.29559	2.611745	6.675805e-07
7.34416	2.611604	6.945223e-07
7.39305	2.611463	7.216435e-07
7.44227	2.611319	7.489452e-07
7.49181	2.611175	7.764287e-07
7.5	2.611151	7.809700e-07
7.54169	2.611029	9.270054e-07
7.59189	2.610881	1.102882e-06
7.64244	2.610732	1.279930e-06
7.69331	2.610582	1.458156e-06
7.74453	2.61043	1.637569e-06
7.79609	2.610276	1.818176e-06
7.84799	2.610121	1.999986e-06
7.90023	2.609964	2.183006e-06
7.95283	2.609805	2.367244e-06
8	2.609662	2.532500e-06
8.00577	2.609645	2.518251e-06
8.05906	2.609483	2.386610e-06
8.11272	2.609319	2.254092e-06
8.16672	2.609153	2.120692e-06
8.22109	2.608986	1.986404e-06
8.27582	2.608816	1.851222e-06
8.33092	2.608645	1.715140e-06
8.38638	2.608472	1.578152e-06
8.44221	2.608297	1.440252e-06
8.49841	2.608119	1.301434e-06
8.5	2.608114	1.297500e-06
8.55498	2.60794	1.321967e-06
8.61194	2.607759	1.347311e-06
8.66927	2.607575	1.372824e-06
8.72698	2.607389	1.398506e-06
8.78508	2.607201	1.424359e-06
8.84356	2.607011	1.450385e-06
8.90243	2.606818	1.476584e-06
8.9617	2.606623	1.502957e-06
9	2.606497	1.520000e-06
9.02136	2.606426	1.520312e-06
9.08142	2.606226	1.521189e-06
9.14187	2.606024	1.522071e-06
9.20273	2.605819	1.522960e-06
9.264	2.605612	1.523854e-06
9.32567	2.605402	1.524755e-06
9.38775	2.605189	1.525661e-06
9.45025	2.604974	1.526574e-06
9.5	2.604802	1.527300e-06
9.51316	2.604756	1.525144e-06
9.57649	2.604535	1.514770e-06
9.64025	2.604311	1.504328e-06
9.70442	2.604084	1.493815e-06
9.76903	2.603855	1.483233e-06
9.83406	2.603622	1.472581e-06
9.89953	2.603386	1.461857e-06
9.96543	2.603147	1.451062e-06
10	2.603021	1.445400e-06
10.0318	2.602905	1.520757e-06
10.0986	2.60266	1.679142e-06
10.1658	2.602411	1.838580e-06
10.2335	2.602159	1.999080e-06
10.3016	2.601904	2.160649e-06
10.3702	2.601645	2.323293e-06
10.4392	2.601383	2.487019e-06
10.5	2.60115	2.631200e-06
10.5087	2.601117	2.682912e-06
10.5787	2.600847	3.098676e-06
10.6491	2.600574	3.517209e-06
10.72	2.600296	3.938527e-06
10.7913	2.600015	4.362650e-06
10.8632	2.59973	4.789597e-06
10.9355	2.599441	5.219386e-06
11	2.599182	5.602700e-06
11.0083	2.599148	5.756616e-06
11.0816	2.598851	7.115357e-06
11.1554	2.59855	8.483143e-06
11.2296	2.598244	9.860034e-06
11.3044	2.597934	1.124609e-05
11.3796	2.597619	1.264138e-05
11.4554	2.5973	1.404595e-05
11.5	2.597111	1.487300e-05
11.5317	2.596976	1.700949e-05
11.6084	2.596648	2.219107e-05
11.6857	2.596315	2.740714e-05
11.7635	2.595977	3.265794e-05
11.8418	2.595633	3.794369e-05
11.9206	2.595285	4.326464e-05
12	2.594932	4.862100e-05

Optical transmission calculator

Free-standing sample in vacuum, normal incidence

Transmittance T: —
Reflectance R: —

Fresnel reflection calculator

R_p: —
R_s: —
R = (R_p+R_s)/2: —
Phase φ_p: —
Phase φ_s: —
Brewster angle θ_B: —
Critical angle θ_C: —

IRG 25 (SCHOTT): all datasets

IRG 25 n,k 0.85–12 µm default

About IRG 25 (SCHOTT)

SCHOTT AG is a German multinational company renowned for its expertise in specialty glass and glass-ceramics. Founded in 1884, the company has been a pioneer in the field, with innovations that have significantly impacted a variety of industries, including healthcare, home appliances, electronics, and optics. In the optical domain, SCHOTT offers a comprehensive range of high-quality glass types, including crown and flint glasses, as well as specialty materials like laser glasses and radiation-shielding glasses. These materials are used in a myriad of applications, from consumer electronics and camera lenses to scientific instruments and aerospace technologies. SCHOTT's glass products are highly regarded for their quality, consistency, and durability, meeting rigorous industry standards. With a strong focus on research and development, the company has continued to introduce innovative products that address the evolving needs of the optical industry. SCHOTT's commitment to quality and innovation has established it as a leading provider of specialty glass solutions, making it a go-to choice for designers and manufacturers seeking high-performance materials. SCHOTT also publishes a glass catalog (SCHOTT Optical Glass Datasheets), which is a standard reference for the properties of many optical glasses.

More about IRG 25 (SCHOTT) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/specs/schott/infrared/IRG25.yml
ID: ds_14d70234020b
API: /v1/datasets/ds_14d70234020b

Plot