Optical constants

Refractive index of H-K51 (CDGM)

H-K51: n,k 0.365–2.325 µm

Data: formula 2 + tabulated k
Range: 0.365–2.325 µm
Temperature: 293 K
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.52307
Extinction coefficient k: 1.87414e-08

Permittivity ε₁: 2.31974
Permittivity ε₂: 5.70890e-08

Absorption coefficient α: 0.00400803 cm⁻¹
Penetration depth δ = λ/(2πk): 4.98998e+09 nm

Abbe number V_d: 58.64
Chromatic dispersion dn/dλ: -0.0460342 µm⁻¹

Group index n_g: 1.55012
Group velocity dispersion: 80.9898 fs²/mm

Dispersion parameter D: -441.842 ps/(nm·km)
Photon energy: 2.11001 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

# H-K51 (CDGM): H-K51
cdgm_h_k51 = ls.fetch_refractiveindex("specs", "CDGM-optical", "H-K51", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(cdgm_h_k51.range_nm)  # (365, 2325) nm
eps = cdgm_h_k51.eps([633])  # 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_d59e234ac7f9/lightsmith"
cdgm_h_k51 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(cdgm_h_k51.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (cdgm-h-k51/cdgm).

# ... load cdgm_h_k51 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=cdgm_h_k51)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=400, 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"]).

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 = \frac{0.960161808 λ^{2}}{λ^{2} - 116.24248} + \frac{1.18368963 λ^{2}}{λ^{2} - 0.0118029997} + \frac{0.102338243 λ^{2}}{λ^{2} + 0.0189575777}

Valid from 0.365 to 2.325 µm.

Coefficients as stored

C_i	Value
C1	0.0
C2	0.960161808
C3	116.24248
C4	1.18368963
C5	0.0118029997
C6	0.102338243
C7	-0.0189575777

Comments and conditions

Conditions

temperature: 293 K

Properties

thermal dispersion: type: formula A, coefficients: -7.23e-07 1.38e-08 -8.37e-11 5.74e-07 1.43e-09 0.169
nd: 1.523070
Vd: 58.639792
glass code: 523586
glass status: standard
density: value: 2530
thermal expansion: value: 8e-06, temperature range: 243 343; value: 9.9e-06, temperature range: 293 573
dPgF: -0.0007
resistance: climatic: 2.0

Thermo-optic coefficient

Schott thermal-dispersion model (reference temperature 293.0 K): dn/dT = 3.54e-07 K⁻¹ at 633 nm, dn/dT = -1.62e-07 K⁻¹ at 1310 nm, dn/dT = -2.03e-07 K⁻¹ at 1550 nm

References

CDGM Zemax catalog 2022-06 (obtained from http://www.cdgmgd.com)
See also CDGM optical glass data sheets

Cite

CDGM Zemax catalog 2022-06 (obtained from http://www.cdgmgd.com); See also CDGM optical 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 425 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

H-K51 (CDGM), H-K51: n and k versus wavelength
λ (µm)	n	k
0.365	1.54507	1.198140e-07
0.366698	1.544723	1.075238e-07
0.368403	1.544379	9.517634e-08
0.37	1.544063	8.361800e-08
0.370117	1.54404	8.331853e-08
0.371838	1.543704	7.890968e-08
0.373568	1.543372	7.448032e-08
0.375306	1.543043	7.003035e-08
0.377051	1.542719	6.555969e-08
0.378805	1.542397	6.106824e-08
0.38	1.542181	5.800800e-08
0.380567	1.542079	5.666532e-08
0.382337	1.541765	5.247362e-08
0.384116	1.541454	4.826243e-08
0.385902	1.541146	4.403165e-08
0.387697	1.540842	3.978118e-08
0.3895	1.54054	3.551095e-08
0.39	1.540458	3.432800e-08
0.391312	1.540243	3.233722e-08
0.393132	1.539948	2.957574e-08
0.394961	1.539656	2.680140e-08
0.396798	1.539368	2.401416e-08
0.398644	1.539082	2.121396e-08
0.4	1.538875	1.915600e-08
0.400498	1.5388	1.917984e-08
0.402361	1.538521	1.926908e-08
0.404232	1.538244	1.935872e-08
0.406112	1.537971	1.944878e-08
0.408001	1.5377	1.953926e-08
0.409899	1.537432	1.963017e-08
0.411806	1.537167	1.972149e-08
0.413721	1.536905	1.981324e-08
0.415645	1.536645	1.990542e-08
0.417579	1.536389	1.999802e-08
0.419521	1.536134	2.009106e-08
0.42	1.536072	2.011400e-08
0.421472	1.535883	2.018453e-08
0.423433	1.535634	2.027843e-08
0.425402	1.535388	2.037277e-08
0.427381	1.535144	2.046755e-08
0.429369	1.534903	2.056277e-08
0.431366	1.534664	2.065843e-08
0.433372	1.534428	2.075454e-08
0.435388	1.534194	2.085110e-08
0.437413	1.533962	2.094810e-08
0.439448	1.533733	2.104556e-08
0.44	1.533672	2.107200e-08
0.441492	1.533506	2.086887e-08
0.443545	1.533282	2.058929e-08
0.445609	1.53306	2.030840e-08
0.447681	1.53284	2.002620e-08
0.449764	1.532622	1.974270e-08
0.451856	1.532406	1.945787e-08
0.453957	1.532193	1.917172e-08
0.456069	1.531982	1.888424e-08
0.45819	1.531773	1.859542e-08
0.46	1.531597	1.834900e-08
0.460321	1.531566	1.836180e-08
0.462462	1.531361	1.844713e-08
0.464613	1.531158	1.853285e-08
0.466775	1.530957	1.861896e-08
0.468946	1.530758	1.870548e-08
0.471127	1.530561	1.879241e-08
0.473318	1.530366	1.887973e-08
0.47552	1.530173	1.896746e-08
0.477732	1.529982	1.905560e-08
0.479954	1.529793	1.914415e-08
0.48	1.529789	1.914600e-08
0.482186	1.529605	1.879633e-08
0.484429	1.529419	1.843760e-08
0.486682	1.529236	1.807719e-08
0.488946	1.529054	1.771511e-08
0.49122	1.528873	1.735134e-08
0.493505	1.528695	1.698589e-08
0.4958	1.528518	1.661873e-08
0.498107	1.528343	1.624986e-08
0.5	1.528201	1.594700e-08
0.500423	1.52817	1.596051e-08
0.502751	1.527998	1.603476e-08
0.505089	1.527828	1.610935e-08
0.507439	1.527659	1.618430e-08
0.509799	1.527492	1.625959e-08
0.51217	1.527327	1.633523e-08
0.514553	1.527163	1.641123e-08
0.516946	1.527001	1.648758e-08
0.51935	1.526841	1.656428e-08
0.521766	1.526681	1.664134e-08
0.524193	1.526524	1.671876e-08
0.526631	1.526368	1.679654e-08
0.529081	1.526213	1.687468e-08
0.531542	1.52606	1.695318e-08
0.534014	1.525908	1.703205e-08
0.536498	1.525757	1.711128e-08
0.538993	1.525608	1.719089e-08
0.5415	1.525461	1.727086e-08
0.544019	1.525314	1.735121e-08
0.546549	1.525169	1.743193e-08
0.549092	1.525026	1.751302e-08
0.55	1.524975	1.754200e-08
0.551646	1.524883	1.759450e-08
0.554212	1.524742	1.767635e-08
0.556789	1.524602	1.775858e-08
0.559379	1.524464	1.784120e-08
0.561981	1.524327	1.792420e-08
0.564595	1.524191	1.800758e-08
0.567221	1.524056	1.809135e-08
0.569859	1.523922	1.817552e-08
0.57251	1.52379	1.826007e-08
0.575173	1.523658	1.834502e-08
0.577848	1.523528	1.843036e-08
0.580536	1.523399	1.851610e-08
0.583236	1.523271	1.860224e-08
0.585949	1.523145	1.868878e-08
0.588675	1.523019	1.877572e-08
0.591413	1.522894	1.886307e-08
0.594164	1.522771	1.895082e-08
0.596927	1.522648	1.903898e-08
0.599704	1.522527	1.912755e-08
0.6	1.522514	1.913700e-08
0.602493	1.522407	1.947562e-08
0.605296	1.522287	1.985625e-08
0.608111	1.522169	2.023864e-08
0.61094	1.522052	2.062281e-08
0.613781	1.521936	2.100876e-08
0.616636	1.52182	2.139652e-08
0.619504	1.521706	2.178607e-08
0.622386	1.521592	2.217744e-08
0.625281	1.52148	2.257063e-08
0.628189	1.521368	2.296565e-08
0.631111	1.521258	2.336250e-08
0.634047	1.521148	2.376120e-08
0.636996	1.521039	2.416176e-08
0.639959	1.520931	2.456417e-08
0.642935	1.520824	2.496846e-08
0.645926	1.520718	2.537463e-08
0.64893	1.520612	2.578269e-08
0.65	1.520575	2.592800e-08
0.651949	1.520508	2.578763e-08
0.654981	1.520404	2.556917e-08
0.658028	1.520301	2.534970e-08
0.661088	1.520199	2.512921e-08
0.664163	1.520098	2.490769e-08
0.667252	1.519997	2.468514e-08
0.670356	1.519897	2.446155e-08
0.673474	1.519798	2.423693e-08
0.676607	1.5197	2.401126e-08
0.679754	1.519602	2.378454e-08
0.682915	1.519506	2.355677e-08
0.686092	1.51941	2.332794e-08
0.689283	1.519314	2.309804e-08
0.692489	1.51922	2.286707e-08
0.69571	1.519126	2.263503e-08
0.698946	1.519032	2.240191e-08
0.7	1.519002	2.232600e-08
0.702197	1.51894	2.239609e-08
0.705463	1.518848	2.250028e-08
0.708745	1.518757	2.260496e-08
0.712041	1.518666	2.271012e-08
0.715353	1.518576	2.281577e-08
0.718681	1.518487	2.292191e-08
0.722023	1.518398	2.302855e-08
0.725382	1.51831	2.313568e-08
0.728756	1.518222	2.324331e-08
0.732146	1.518135	2.335144e-08
0.735551	1.518049	2.346008e-08
0.738972	1.517963	2.356922e-08
0.742409	1.517878	2.367886e-08
0.745863	1.517793	2.378902e-08
0.749332	1.517709	2.389969e-08
0.752817	1.517626	2.401087e-08
0.756319	1.517543	2.412257e-08
0.759837	1.51746	2.423479e-08
0.763371	1.517378	2.434754e-08
0.766922	1.517297	2.446080e-08
0.770489	1.517216	2.457460e-08
0.774073	1.517135	2.468892e-08
0.777673	1.517055	2.480378e-08
0.78129	1.516976	2.491916e-08
0.784924	1.516897	2.503509e-08
0.788575	1.516818	2.515156e-08
0.792243	1.51674	2.526856e-08
0.795928	1.516663	2.538611e-08
0.79963	1.516585	2.550421e-08
0.8	1.516578	2.551600e-08
0.80335	1.516509	2.516809e-08
0.807086	1.516432	2.478000e-08
0.81084	1.516356	2.439011e-08
0.814612	1.516281	2.399840e-08
0.818401	1.516206	2.360487e-08
0.822208	1.516131	2.320952e-08
0.826032	1.516057	2.281232e-08
0.829874	1.515983	2.241327e-08
0.833734	1.515909	2.201237e-08
0.837612	1.515836	2.160960e-08
0.841508	1.515763	2.120496e-08
0.845422	1.515691	2.079844e-08
0.849355	1.515619	2.039003e-08
0.85	1.515607	2.032300e-08
0.853305	1.515547	1.992736e-08
0.857274	1.515476	1.945227e-08
0.861262	1.515404	1.897497e-08
0.865268	1.515334	1.849545e-08
0.869292	1.515263	1.801370e-08
0.873336	1.515193	1.752971e-08
0.877398	1.515123	1.704347e-08
0.881479	1.515054	1.655497e-08
0.885579	1.514984	1.606419e-08
0.889698	1.514915	1.557113e-08
0.893836	1.514847	1.507578e-08
0.897994	1.514778	1.457812e-08
0.9	1.514745	1.433800e-08
0.902171	1.51471	1.437260e-08
0.906367	1.514642	1.443949e-08
0.910583	1.514574	1.450669e-08
0.914818	1.514507	1.457420e-08
0.919073	1.51444	1.464203e-08
0.923348	1.514373	1.471017e-08
0.927643	1.514306	1.477863e-08
0.931958	1.514239	1.484741e-08
0.936293	1.514173	1.491651e-08
0.940648	1.514107	1.498593e-08
0.945023	1.514041	1.505567e-08
0.949419	1.513975	1.512573e-08
0.95	1.513967	1.513500e-08
0.953835	1.51391	1.519605e-08
0.958271	1.513844	1.526668e-08
0.962729	1.513779	1.533764e-08
0.967207	1.513714	1.540893e-08
0.971705	1.513649	1.548055e-08
0.976225	1.513585	1.555250e-08
0.980766	1.51352	1.562479e-08
0.985328	1.513456	1.569742e-08
0.989911	1.513391	1.577038e-08
0.994515	1.513327	1.584368e-08
0.999141	1.513263	1.591732e-08
1	1.513252	1.593100e-08
1.00379	1.513199	1.599136e-08
1.00846	1.513136	1.606575e-08
1.01315	1.513072	1.614049e-08
1.01786	1.513009	1.621558e-08
1.02259	1.512945	1.629101e-08
1.02735	1.512882	1.636680e-08
1.03213	1.512818	1.644293e-08
1.03693	1.512755	1.651943e-08
1.04175	1.512692	1.659628e-08
1.0466	1.512629	1.667348e-08
1.05147	1.512566	1.675105e-08
1.05636	1.512503	1.682897e-08
1.06	1.512456	1.688700e-08
1.06127	1.51244	1.690726e-08
1.06621	1.512377	1.698593e-08
1.07117	1.512315	1.706496e-08
1.07615	1.512252	1.714435e-08
1.08115	1.512189	1.722412e-08
1.08618	1.512126	1.730426e-08
1.09124	1.512064	1.738477e-08
1.09631	1.512001	1.746565e-08
1.10141	1.511938	1.754691e-08
1.10653	1.511876	1.762855e-08
1.11168	1.511813	1.771057e-08
1.11685	1.51175	1.779297e-08
1.12205	1.511687	1.787576e-08
1.12727	1.511625	1.795892e-08
1.13251	1.511562	1.804248e-08
1.13778	1.511499	1.812642e-08
1.14307	1.511436	1.821076e-08
1.14839	1.511373	1.829549e-08
1.15373	1.51131	1.838061e-08
1.15909	1.511247	1.846612e-08
1.16448	1.511184	1.855204e-08
1.1699	1.511121	1.863835e-08
1.17534	1.511058	1.872507e-08
1.18081	1.510994	1.881219e-08
1.1863	1.510931	1.889971e-08
1.19182	1.510867	1.898764e-08
1.19736	1.510804	1.907598e-08
1.2	1.510774	1.911800e-08
1.20293	1.51074	1.932849e-08
1.20853	1.510676	1.973009e-08
1.21415	1.510612	2.013356e-08
1.2198	1.510548	2.053890e-08
1.22547	1.510484	2.094613e-08
1.23117	1.51042	2.135525e-08
1.2369	1.510355	2.176628e-08
1.24265	1.51029	2.217921e-08
1.24843	1.510226	2.259407e-08
1.25424	1.510161	2.301086e-08
1.26007	1.510096	2.342958e-08
1.26593	1.51003	2.385026e-08
1.27182	1.509965	2.427289e-08
1.27774	1.509899	2.469748e-08
1.28368	1.509833	2.512405e-08
1.28965	1.509767	2.555261e-08
1.29565	1.509701	2.598316e-08
1.30167	1.509635	2.641571e-08
1.30773	1.509568	2.685027e-08
1.31381	1.509501	2.728686e-08
1.31992	1.509434	2.772547e-08
1.32606	1.509367	2.816613e-08
1.33223	1.509299	2.860883e-08
1.33843	1.509231	2.905360e-08
1.34465	1.509163	2.950043e-08
1.35091	1.509095	2.994934e-08
1.35719	1.509026	3.040034e-08
1.3635	1.508957	3.085344e-08
1.36985	1.508888	3.130864e-08
1.37622	1.508818	3.176596e-08
1.38262	1.508749	3.222541e-08
1.38905	1.508679	3.268700e-08
1.39551	1.508608	3.315073e-08
1.4	1.508559	3.347300e-08
1.402	1.508538	3.352084e-08
1.40852	1.508467	3.367676e-08
1.41507	1.508395	3.383341e-08
1.42166	1.508324	3.399079e-08
1.42827	1.508252	3.414889e-08
1.43491	1.508179	3.430774e-08
1.44159	1.508107	3.446732e-08
1.44829	1.508034	3.462764e-08
1.45503	1.50796	3.478871e-08
1.4618	1.507886	3.495053e-08
1.46859	1.507812	3.511310e-08
1.47543	1.507738	3.527643e-08
1.48229	1.507663	3.544051e-08
1.48918	1.507587	3.560536e-08
1.49611	1.507512	3.577098e-08
1.50307	1.507436	3.593737e-08
1.51006	1.507359	3.610453e-08
1.51708	1.507282	3.627247e-08
1.52414	1.507204	3.644119e-08
1.53123	1.507127	3.661069e-08
1.53835	1.507048	3.678099e-08
1.54551	1.506969	3.695207e-08
1.5527	1.50689	3.712395e-08
1.55992	1.50681	3.729663e-08
1.56717	1.50673	3.747012e-08
1.57446	1.506649	3.764441e-08
1.58179	1.506568	3.781951e-08
1.58914	1.506486	3.799542e-08
1.59654	1.506404	3.817216e-08
1.6	1.506365	3.825500e-08
1.60396	1.506321	4.584640e-08
1.61142	1.506238	6.014399e-08
1.61892	1.506154	7.450808e-08
1.62645	1.50607	8.893899e-08
1.63401	1.505985	1.034370e-07
1.64161	1.505899	1.180025e-07
1.64925	1.505813	1.326357e-07
1.65692	1.505726	1.473370e-07
1.66463	1.505639	1.621066e-07
1.67237	1.505551	1.769450e-07
1.68015	1.505463	1.918524e-07
1.68796	1.505374	2.068291e-07
1.69581	1.505284	2.218754e-07
1.7037	1.505193	2.369918e-07
1.71163	1.505102	2.521785e-07
1.71959	1.505011	2.674358e-07
1.72759	1.504918	2.827641e-07
1.73562	1.504825	2.981636e-07
1.74369	1.504732	3.136348e-07
1.75181	1.504637	3.291780e-07
1.75995	1.504542	3.447935e-07
1.76814	1.504447	3.604816e-07
1.77636	1.50435	3.762426e-07
1.78463	1.504253	3.920770e-07
1.79293	1.504155	4.079850e-07
1.8	1.504071	4.215400e-07
1.80127	1.504056	4.256443e-07
1.80964	1.503957	4.527966e-07
1.81806	1.503857	4.800753e-07
1.82652	1.503756	5.074808e-07
1.83501	1.503654	5.350138e-07
1.84355	1.503551	5.626748e-07
1.85212	1.503448	5.904646e-07
1.86074	1.503344	6.183835e-07
1.86939	1.503239	6.464324e-07
1.87809	1.503133	6.746117e-07
1.88682	1.503026	7.029221e-07
1.8956	1.502919	7.313641e-07
1.90442	1.50281	7.599385e-07
1.91328	1.502701	7.886457e-07
1.92218	1.502591	8.174865e-07
1.93112	1.502479	8.464614e-07
1.9401	1.502367	8.755712e-07
1.94912	1.502254	9.048163e-07
1.95819	1.50214	9.341974e-07
1.9673	1.502026	9.637152e-07
1.97645	1.50191	9.933703e-07
1.98564	1.501793	1.023163e-06
1.99488	1.501675	1.053095e-06
2	1.501609	1.069700e-06
2.00416	1.501556	1.105305e-06
2.01348	1.501436	1.185185e-06
2.02284	1.501315	1.265437e-06
2.03225	1.501193	1.346061e-06
2.0417	1.501071	1.427061e-06
2.0512	1.500946	1.508438e-06
2.06074	1.500821	1.590193e-06
2.07033	1.500695	1.672329e-06
2.07996	1.500568	1.754846e-06
2.08963	1.500439	1.837748e-06
2.09935	1.50031	1.921035e-06
2.10912	1.500179	2.004709e-06
2.11893	1.500047	2.088772e-06
2.12878	1.499914	2.173227e-06
2.13868	1.49978	2.258074e-06
2.14863	1.499644	2.343316e-06
2.15862	1.499508	2.428955e-06
2.16867	1.49937	2.514992e-06
2.17875	1.49923	2.601429e-06
2.18889	1.49909	2.688268e-06
2.19907	1.498948	2.775511e-06
2.2	1.498935	2.783500e-06
2.2093	1.498805	2.824892e-06
2.21957	1.498661	2.870646e-06
2.2299	1.498515	2.916614e-06
2.24027	1.498368	2.962795e-06
2.25069	1.49822	3.009191e-06
2.26116	1.49807	3.055803e-06
2.27167	1.497919	3.102632e-06
2.28224	1.497766	3.149678e-06
2.29286	1.497612	3.196943e-06
2.30352	1.497457	3.244429e-06
2.31424	1.4973	3.292135e-06
2.325	1.497141	3.340062e-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: —

H-K51 (CDGM): all datasets

K (Crown)

H-K51 n,k 0.365–2.325 µm default

About H-K51 (CDGM)

CDGM Glass Co., Ltd. is a leading manufacturer of optical glass based in China. The company offers a wide range of optical materials, including various types of crown and flint glasses, which are used in applications ranging from consumer electronics to advanced scientific instruments. Known for their capacity for large-scale production as well as their commitment to quality, CDGM has positioned itself as a major player in both domestic and international markets. Their optical glass products are often used in lenses, prisms, and other optical components that require high precision and reliability. With an extensive catalog that caters to different optical requirements, such as high refractive indices or low dispersion, CDGM serves a diverse clientele including manufacturers of microscopes, telescopes, cameras, and other high-precision optical equipment. The company's expertise in glass science and its ability to provide customized solutions have made it a go-to supplier for businesses seeking high-quality, reliable optical glass.

More about H-K51 (CDGM) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/specs/cdgm/optical/H-K51.yml
ID: ds_d59e234ac7f9
API: /v1/datasets/ds_d59e234ac7f9

Plot