Optical constants

Refractive index of IRG 26 (SCHOTT)

IRG 26: 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: 2.79974
Extinction coefficient k: 1.02789e-06

Permittivity ε₁: 7.83855
Permittivity ε₂: 5.75566e-06

Absorption coefficient α: 0.0404917 cm⁻¹
Penetration depth δ = λ/(2πk): 4.93928e+08 nm

Abbe number V_d: —
Chromatic dispersion dn/dλ: -0.008333 µm⁻¹

Group index n_g: 2.82632
Group velocity dispersion: 404.715 fs²/mm

Dispersion parameter D: -74.915 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 26 (SCHOTT): IRG 26
schott_irg26 = ls.fetch_refractiveindex("specs", "SCHOTT-infrared", "IRG26", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(schott_irg26.range_nm)  # (850, 12000) nm
eps = schott_irg26.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_fd435b2e8f71/lightsmith"
schott_irg26 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(schott_irg26.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (schott-irg26/schott).

# ... load schott_irg26 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=schott_irg26)],
    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_fd435b2e8f71/lightsmith?model=drude_lorentz"
schott_irg26_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 = 3.1934 + \frac{3.5854 λ^{2}}{λ^{2} - 0.1852} + \frac{2.2337 λ^{2}}{λ^{2} - 3398.08}

Valid from 0.85 to 12.0 µm.

Coefficients as stored

C_i	Value
C1	3.1934
C2	3.5854
C3	0.1852
C4	2.2337
C5	3398.08

Comments and conditions

Conditions

temperature: 293 K

Properties

thermal dispersion: type: formula A, coefficients: 2.63e-05 0 0 2.93e-05 0 3.15e-01
density: value: 4630
thermal expansion: value: 21.4e-06, temperature range: 293 373
specific heat: value: 360
thermal conductivity: value: 0.24
transformation temperature: value: 458
hardness: type: Knoop, value: 1.04e9
fracture toughness: value: 0.285e6
youngs modulus: value: 18.3e9

Thermo-optic coefficient

Schott thermal-dispersion model (reference temperature 293.0 K): dn/dT = 5.59e-05 K⁻¹ at 1310 nm, dn/dT = 4.86e-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 26 Product flyer (Version April 2017)

Cite

SCHOTT Infrared Chalcogenide Glasses - IRG 26 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 26 (SCHOTT), IRG 26: n and k versus wavelength
λ (µm)	n	k
0.85	3.00236	0
0.855659	2.998725	0
0.861355	2.995165	0
0.867089	2.99168	0
0.872862	2.988266	0
0.878672	2.984921	0
0.884522	2.981645	0
0.89041	2.978435	0
0.896338	2.975289	0
0.902305	2.972206	0
0.908312	2.969185	0
0.914359	2.966223	0
0.920446	2.963319	0
0.926573	2.960471	0
0.932742	2.957679	0
0.938951	2.954941	0
0.945202	2.952256	0
0.951495	2.949622	0
0.957829	2.947038	0
0.964205	2.944502	0
0.970624	2.942015	0
0.977086	2.939574	0
0.983591	2.937179	0
0.990139	2.934828	0
0.99673	2.93252	0
1	2.931397	9.721800e-07
1.00337	2.930255	9.691676e-07
1.01005	2.928031	9.631888e-07
1.01677	2.925848	9.571702e-07
1.02354	2.923704	9.511115e-07
1.03035	2.921599	9.450125e-07
1.03721	2.919532	9.388730e-07
1.04412	2.917502	9.326925e-07
1.05107	2.915508	9.264709e-07
1.05806	2.91355	9.202078e-07
1.06511	2.911626	9.139031e-07
1.0722	2.909736	9.075564e-07
1.07934	2.907879	9.011675e-07
1.08652	2.906055	8.947360e-07
1.09376	2.904262	8.882617e-07
1.10104	2.902501	8.817443e-07
1.10837	2.90077	8.751835e-07
1.11574	2.899068	8.685790e-07
1.12317	2.897396	8.619306e-07
1.13065	2.895752	8.552379e-07
1.13818	2.894137	8.485006e-07
1.14575	2.892549	8.417185e-07
1.15338	2.890987	8.348913e-07
1.16106	2.889452	8.280186e-07
1.16879	2.887943	8.211001e-07
1.17657	2.886459	8.141356e-07
1.1844	2.884999	8.071248e-07
1.19229	2.883564	8.000672e-07
1.20022	2.882153	7.929627e-07
1.20822	2.880765	7.858109e-07
1.21626	2.8794	7.786114e-07
1.22436	2.878057	7.713641e-07
1.23251	2.876736	7.640684e-07
1.24071	2.875437	7.567243e-07
1.24897	2.874159	7.493312e-07
1.25729	2.872902	7.418889e-07
1.26566	2.871665	7.343971e-07
1.27408	2.870448	7.268554e-07
1.28256	2.86925	7.192634e-07
1.2911	2.868072	7.116210e-07
1.2997	2.866912	7.039276e-07
1.30835	2.865771	6.961831e-07
1.31706	2.864648	6.883870e-07
1.32583	2.863543	6.805390e-07
1.33465	2.862456	6.726387e-07
1.34354	2.861385	6.646859e-07
1.35248	2.860332	6.566801e-07
1.36149	2.859295	6.486210e-07
1.37055	2.858274	6.405082e-07
1.37967	2.857269	6.323415e-07
1.38886	2.85628	6.241204e-07
1.3981	2.855306	6.158445e-07
1.40741	2.854347	6.075136e-07
1.41678	2.853403	5.991272e-07
1.42621	2.852474	5.906850e-07
1.43571	2.851559	5.821865e-07
1.44527	2.850658	5.736315e-07
1.45489	2.84977	5.650196e-07
1.46457	2.848897	5.563503e-07
1.47432	2.848036	5.476233e-07
1.48414	2.847189	5.388382e-07
1.49402	2.846355	5.299946e-07
1.5	2.845858	5.246400e-07
1.50396	2.845533	5.240641e-07
1.51398	2.844723	5.226093e-07
1.52405	2.843926	5.211448e-07
1.5342	2.843141	5.196706e-07
1.54441	2.842368	5.181866e-07
1.5547	2.841606	5.166927e-07
1.56505	2.840856	5.151889e-07
1.57546	2.840116	5.136750e-07
1.58595	2.839388	5.121511e-07
1.59651	2.838671	5.106170e-07
1.60714	2.837964	5.090727e-07
1.61784	2.837268	5.075181e-07
1.62861	2.836582	5.059532e-07
1.63945	2.835906	5.043778e-07
1.65036	2.83524	5.027920e-07
1.66135	2.834584	5.011956e-07
1.67241	2.833937	4.995886e-07
1.68355	2.8333	4.979709e-07
1.69475	2.832672	4.963424e-07
1.70604	2.832054	4.947031e-07
1.71739	2.831444	4.930529e-07
1.72883	2.830843	4.913916e-07
1.74033	2.830251	4.897194e-07
1.75192	2.829668	4.880360e-07
1.76358	2.829093	4.863413e-07
1.77532	2.828526	4.846354e-07
1.78714	2.827967	4.829182e-07
1.79904	2.827417	4.811895e-07
1.81102	2.826874	4.794493e-07
1.82307	2.826339	4.776975e-07
1.83521	2.825812	4.759340e-07
1.84743	2.825292	4.741589e-07
1.85973	2.824779	4.723719e-07
1.87211	2.824274	4.705730e-07
1.88457	2.823776	4.687621e-07
1.89712	2.823285	4.669392e-07
1.90974	2.822801	4.651041e-07
1.92246	2.822324	4.632568e-07
1.93526	2.821853	4.613972e-07
1.94814	2.821389	4.595253e-07
1.96111	2.820932	4.576408e-07
1.97416	2.820481	4.557439e-07
1.98731	2.820036	4.538343e-07
2	2.819615	4.519900e-07
2.00054	2.819598	4.520455e-07
2.01386	2.819165	4.534223e-07
2.02726	2.818739	4.548083e-07
2.04076	2.818318	4.562035e-07
2.05434	2.817904	4.576080e-07
2.06802	2.817495	4.590219e-07
2.08179	2.817091	4.604451e-07
2.09565	2.816694	4.618779e-07
2.1096	2.816301	4.633201e-07
2.12364	2.815914	4.647720e-07
2.13778	2.815533	4.662335e-07
2.15201	2.815156	4.677048e-07
2.16634	2.814785	4.691859e-07
2.18076	2.814419	4.706768e-07
2.19528	2.814057	4.721776e-07
2.20989	2.813701	4.736885e-07
2.2246	2.813349	4.752094e-07
2.23941	2.813002	4.767404e-07
2.25432	2.81266	4.782816e-07
2.26933	2.812323	4.798331e-07
2.28443	2.81199	4.813949e-07
2.29964	2.811661	4.829671e-07
2.31495	2.811337	4.845497e-07
2.33036	2.811017	4.861430e-07
2.34588	2.810701	4.877468e-07
2.36149	2.810389	4.893612e-07
2.37721	2.810082	4.909865e-07
2.39304	2.809779	4.926225e-07
2.40897	2.809479	4.942695e-07
2.42501	2.809184	4.959274e-07
2.44115	2.808892	4.975963e-07
2.4574	2.808605	4.992764e-07
2.47376	2.808321	5.009676e-07
2.49023	2.80804	5.026701e-07
2.5	2.807877	5.036800e-07
2.50681	2.807764	5.165924e-07
2.5235	2.80749	5.482375e-07
2.5403	2.807221	5.800934e-07
2.55721	2.806955	6.121612e-07
2.57423	2.806692	6.444426e-07
2.59137	2.806433	6.769389e-07
2.60862	2.806177	7.096515e-07
2.62599	2.805924	7.425819e-07
2.64347	2.805674	7.757315e-07
2.66107	2.805428	8.091018e-07
2.67878	2.805184	8.426942e-07
2.69662	2.804944	8.765103e-07
2.71457	2.804707	9.105515e-07
2.73264	2.804472	9.448193e-07
2.75083	2.804241	9.793152e-07
2.76914	2.804012	1.014041e-06
2.78758	2.803787	1.048998e-06
2.80614	2.803564	1.084187e-06
2.82482	2.803343	1.119611e-06
2.84362	2.803126	1.155270e-06
2.86255	2.802911	1.191167e-06
2.88161	2.802699	1.227303e-06
2.90079	2.802489	1.263680e-06
2.9201	2.802282	1.300298e-06
2.93954	2.802077	1.337161e-06
2.95911	2.801874	1.374269e-06
2.97881	2.801674	1.411624e-06
2.99864	2.801477	1.449227e-06
3	2.801464	1.451800e-06
3.01861	2.801282	1.410289e-06
3.0387	2.801089	1.365454e-06
3.05893	2.800898	1.320320e-06
3.07929	2.800709	1.274886e-06
3.09979	2.800523	1.229149e-06
3.12043	2.800339	1.183109e-06
3.1412	2.800157	1.136761e-06
3.16212	2.799977	1.090105e-06
3.18317	2.799799	1.043138e-06
3.20436	2.799623	9.958592e-07
3.22569	2.799449	9.482651e-07
3.24716	2.799276	9.003543e-07
3.26878	2.799106	8.521245e-07
3.29054	2.798938	8.035736e-07
3.31245	2.798771	7.546995e-07
3.3345	2.798607	7.055000e-07
3.3567	2.798444	6.559730e-07
3.37904	2.798282	6.061163e-07
3.40154	2.798123	5.559277e-07
3.42418	2.797965	5.054049e-07
3.44698	2.797809	4.545458e-07
3.46993	2.797654	4.033482e-07
3.49303	2.797501	3.518097e-07
3.5	2.797455	3.362500e-07
3.51628	2.797349	3.325822e-07
3.53969	2.7972	3.273082e-07
3.56325	2.797051	3.219991e-07
3.58697	2.796904	3.166547e-07
3.61085	2.796759	3.112747e-07
3.63489	2.796614	3.058589e-07
3.65909	2.796472	3.004070e-07
3.68345	2.79633	2.949189e-07
3.70797	2.79619	2.893942e-07
3.73266	2.796052	2.838327e-07
3.7575	2.795914	2.782342e-07
3.78252	2.795778	2.725984e-07
3.8077	2.795643	2.669251e-07
3.83305	2.795509	2.612141e-07
3.85857	2.795377	2.554650e-07
3.88425	2.795245	2.496777e-07
3.91011	2.795115	2.438518e-07
3.93614	2.794986	2.379871e-07
3.96235	2.794858	2.320834e-07
3.98872	2.794731	2.261404e-07
4	2.794677	2.236000e-07
4.01528	2.794605	2.222525e-07
4.04201	2.79448	2.198948e-07
4.06892	2.794356	2.175215e-07
4.096	2.794233	2.151324e-07
4.12327	2.794111	2.127273e-07
4.15072	2.79399	2.103063e-07
4.17835	2.793869	2.078691e-07
4.20617	2.79375	2.054157e-07
4.23417	2.793631	2.029460e-07
4.26236	2.793514	2.004599e-07
4.29074	2.793397	1.979571e-07
4.3193	2.793281	1.954378e-07
4.34805	2.793165	1.929016e-07
4.377	2.793051	1.903486e-07
4.40614	2.792937	1.877786e-07
4.43547	2.792824	1.851914e-07
4.465	2.792711	1.825871e-07
4.49472	2.7926	1.799654e-07
4.5	2.79258	1.795000e-07
4.52465	2.792488	1.804829e-07
4.55477	2.792378	1.816841e-07
4.58509	2.792268	1.828934e-07
4.61561	2.792159	1.841107e-07
4.64634	2.79205	1.853361e-07
4.67727	2.791942	1.865696e-07
4.70841	2.791834	1.878114e-07
4.73975	2.791727	1.890614e-07
4.77131	2.79162	1.903198e-07
4.80307	2.791514	1.915865e-07
4.83505	2.791408	1.928617e-07
4.86723	2.791302	1.941453e-07
4.89964	2.791197	1.954375e-07
4.93226	2.791093	1.967383e-07
4.96509	2.790988	1.980478e-07
4.99814	2.790884	1.993660e-07
5	2.790879	1.994400e-07
5.03142	2.790781	2.006936e-07
5.06491	2.790678	2.020300e-07
5.09863	2.790575	2.033754e-07
5.13257	2.790472	2.047297e-07
5.16674	2.790369	2.060930e-07
5.20114	2.790267	2.074654e-07
5.23576	2.790165	2.088470e-07
5.27062	2.790063	2.102377e-07
5.30571	2.789962	2.116377e-07
5.34103	2.78986	2.130470e-07
5.37658	2.789759	2.144657e-07
5.41238	2.789657	2.158939e-07
5.44841	2.789556	2.173315e-07
5.48468	2.789455	2.187787e-07
5.5	2.789413	2.193900e-07
5.52119	2.789354	2.222701e-07
5.55795	2.789253	2.272652e-07
5.59495	2.789152	2.322935e-07
5.6322	2.789051	2.373554e-07
5.66969	2.78895	2.424509e-07
5.70743	2.788849	2.475804e-07
5.74543	2.788748	2.527440e-07
5.78368	2.788647	2.579419e-07
5.82218	2.788546	2.631745e-07
5.86094	2.788445	2.684419e-07
5.89996	2.788343	2.737444e-07
5.93924	2.788242	2.790822e-07
5.97878	2.78814	2.844555e-07
6	2.788086	2.873400e-07
6.01858	2.788038	2.901641e-07
6.05864	2.787936	2.962551e-07
6.09898	2.787834	3.023866e-07
6.13958	2.787731	3.085589e-07
6.18045	2.787629	3.147724e-07
6.2216	2.787526	3.210272e-07
6.26302	2.787422	3.273236e-07
6.30471	2.787319	3.336620e-07
6.34668	2.787215	3.400425e-07
6.38893	2.78711	3.464655e-07
6.43147	2.787006	3.529313e-07
6.47428	2.7869	3.594402e-07
6.5	2.786837	3.633500e-07
6.51738	2.786795	3.584801e-07
6.56077	2.786689	3.463237e-07
6.60445	2.786583	3.340865e-07
6.64841	2.786476	3.217677e-07
6.69267	2.786368	3.093670e-07
6.73723	2.786261	2.968837e-07
6.78208	2.786152	2.843173e-07
6.82723	2.786043	2.716672e-07
6.87268	2.785934	2.589330e-07
6.91843	2.785824	2.461139e-07
6.96449	2.785713	2.332095e-07
7	2.785628	2.232600e-07
7.01085	2.785602	2.249075e-07
7.05753	2.78549	2.319924e-07
7.10451	2.785377	2.391245e-07
7.15181	2.785264	2.463040e-07
7.19942	2.78515	2.535314e-07
7.24734	2.785035	2.608069e-07
7.29559	2.784919	2.681308e-07
7.34416	2.784803	2.755035e-07
7.39305	2.784686	2.829252e-07
7.44227	2.784568	2.903964e-07
7.49181	2.784449	2.979173e-07
7.5	2.784429	2.991600e-07
7.54169	2.784329	3.115030e-07
7.59189	2.784209	3.263681e-07
7.64244	2.784087	3.413323e-07
7.69331	2.783965	3.563960e-07
7.74453	2.783841	3.715601e-07
7.79609	2.783717	3.868251e-07
7.84799	2.783591	4.021917e-07
7.90023	2.783465	4.176606e-07
7.95283	2.783337	4.332325e-07
8	2.783223	4.472000e-07
8.00577	2.783209	4.554218e-07
8.05906	2.783079	5.313794e-07
8.11272	2.782948	6.078427e-07
8.16672	2.782816	6.848150e-07
8.22109	2.782683	7.622997e-07
8.27582	2.782548	8.403003e-07
8.33092	2.782413	9.188201e-07
8.38638	2.782276	9.978627e-07
8.44221	2.782137	1.077431e-06
8.49841	2.781998	1.157530e-06
8.5	2.781994	1.159800e-06
8.55498	2.781857	1.502838e-06
8.61194	2.781715	1.858164e-06
8.66927	2.781571	2.215855e-06
8.72698	2.781426	2.575927e-06
8.78508	2.781279	2.938397e-06
8.84356	2.781131	3.303279e-06
8.90243	2.780981	3.670591e-06
8.9617	2.78083	4.040348e-06
9	2.780732	4.279300e-06
9.02136	2.780677	4.168329e-06
9.08142	2.780523	3.856321e-06
9.14187	2.780367	3.542235e-06
9.20273	2.780209	3.226058e-06
9.264	2.78005	2.907776e-06
9.32567	2.779889	2.587376e-06
9.38775	2.779726	2.264842e-06
9.45025	2.779561	1.940162e-06
9.5	2.77943	1.681700e-06
9.51316	2.779395	1.712063e-06
9.57649	2.779226	1.858155e-06
9.64025	2.779056	2.005220e-06
9.70442	2.778884	2.153264e-06
9.76903	2.778709	2.302293e-06
9.83406	2.778533	2.452315e-06
9.89953	2.778355	2.603335e-06
9.96543	2.778174	2.755361e-06
10	2.778079	2.835100e-06
10.0318	2.777992	2.921712e-06
10.0986	2.777807	3.103751e-06
10.1658	2.77762	3.287002e-06
10.2335	2.777431	3.471473e-06
10.3016	2.77724	3.657171e-06
10.3702	2.777046	3.844106e-06
10.4392	2.77685	4.032286e-06
10.5	2.776676	4.198000e-06
10.5087	2.776651	4.172914e-06
10.5787	2.77645	3.971223e-06
10.6491	2.776247	3.768190e-06
10.72	2.776041	3.563804e-06
10.7913	2.775832	3.358059e-06
10.8632	2.775621	3.150943e-06
10.9355	2.775407	2.942449e-06
11	2.775215	2.756500e-06
11.0083	2.775191	2.763292e-06
11.0816	2.774971	2.823254e-06
11.1554	2.774749	2.883614e-06
11.2296	2.774524	2.944377e-06
11.3044	2.774296	3.005544e-06
11.3796	2.774065	3.067118e-06
11.4554	2.773832	3.129102e-06
11.5	2.773693	3.165600e-06
11.5317	2.773595	3.294405e-06
11.6084	2.773355	3.606792e-06
11.6857	2.773111	3.921259e-06
11.7635	2.772865	4.237819e-06
11.8418	2.772615	4.556486e-06
11.9206	2.772362	4.877275e-06
12	2.772106	5.200200e-06

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 26 (SCHOTT): all datasets

IRG 26 n,k 0.85–12 µm default

About IRG 26 (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 26 (SCHOTT) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/specs/schott/infrared/IRG26.yml
ID: ds_fd435b2e8f71
API: /v1/datasets/ds_fd435b2e8f71

Plot