At one wavelength

Refractive index n: 2.20157
Extinction coefficient k: 0

Permittivity ε₁: 4.8469
Permittivity ε₂: 0

Absorption coefficient α: 0 cm⁻¹
Penetration depth δ = λ/(2πk): — nm

Abbe number V_d: —
Chromatic dispersion dn/dλ: -0.227437 µm⁻¹

Group index n_g: 2.33521
Group velocity dispersion: — fs²/mm

Dispersion parameter D: — 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

# Ta2O5 (Tantalum pentoxide): Cheikh et al. 2025: Power 3.28, O2 8, Anneal. 850; n,k 0.207–1.24 µm
ta2o5 = ls.fetch_refractiveindex("main", "Ta2O5", "Cheikh-crystalline-3.28-8-850", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(ta2o5.range_nm)  # (206.67, 1240) nm
eps = ta2o5.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_4e0b66a42111/lightsmith"
ta2o5 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(ta2o5.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (ta2o5/cheikh-2025-crystalline-3-28-8-850).

# ... load ta2o5 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=ta2o5)],
    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.

Comments and conditions

Ta₂O₅ Crystalline (orthorhombic) thin film. Deposited by radio frequency magnetron sputtering at sputtering power density 3.28 W/cm² under oxygen flow of 8 sccm. Annealed at 850 °C.

References

A. Cheikh, J. Gonçalves, C. Labbé, X. Portier, P. Marie, C. Frilay, O. Debieu, S. Duprey, W. Jadwisienczak, D. Ingram, J. Cardin. Tailoring the structural and optical properties of Ta₂O₅ thin films via radio frequency magnetron sputtering for high-refractive index transparent materials. J. Alloys Compd. 1040, 183273 (2025) (Numerical data kindly provided by Julien Cardin)

doi:10.1016/j.jallcom.2025.183273 Tailoring structural and optical properties of Ta2O5 thin films via radio frequency magnetron sputtering for high-refractive index transparent materials, Journal of Alloys and Compounds (2025)

Cite

Aïmane Cheikh et al.. Tailoring structural and optical properties of Ta2O5 thin films via radio frequency magnetron sputtering for high-refractive index transparent materials. Journal of Alloys and Compounds, 1040, 183273 (2025), doi:10.1016/j.jallcom.2025.183273; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)

Data

501 rows as published

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

Ta2O5 (Tantalum pentoxide), Cheikh et al. 2025: Power 3.28, O2 8, Anneal. 850; n,k 0.207–1.24 µm: n and k versus wavelength
λ (µm)	n	k
0.20667	2.07778	1.5599
0.20701	2.09553	1.55943
0.20736	2.11336	1.55859
0.20771	2.13126	1.55736
0.20805	2.1492	1.55574
0.2084	2.16719	1.55373
0.20875	2.1852	1.55132
0.20911	2.20322	1.54851
0.20946	2.22125	1.54529
0.20981	2.23926	1.54166
0.21017	2.25724	1.53762
0.21053	2.27517	1.53316
0.21088	2.29305	1.52829
0.21124	2.31086	1.523
0.2116	2.32858	1.51729
0.21197	2.3462	1.51117
0.21233	2.3637	1.50464
0.21269	2.38107	1.49769
0.21306	2.39829	1.49034
0.21343	2.41535	1.48258
0.21379	2.43222	1.47443
0.21416	2.44891	1.46588
0.21453	2.46538	1.45694
0.2149	2.48164	1.44763
0.21528	2.49765	1.43794
0.21565	2.51342	1.42789
0.21603	2.52892	1.41748
0.2164	2.54415	1.40673
0.21678	2.55909	1.39565
0.21716	2.57372	1.38424
0.21754	2.58805	1.37253
0.21793	2.60205	1.36051
0.21831	2.61572	1.34822
0.21869	2.62905	1.33565
0.21908	2.64203	1.32282
0.21947	2.65466	1.30975
0.21986	2.66692	1.29645
0.22025	2.6788	1.28293
0.22064	2.69032	1.26922
0.22103	2.70145	1.25532
0.22143	2.7122	1.24125
0.22182	2.72256	1.22703
0.22222	2.73254	1.21266
0.22262	2.74212	1.19818
0.22302	2.75131	1.18358
0.22342	2.76011	1.16889
0.22383	2.76852	1.15412
0.22423	2.77654	1.13928
0.22464	2.78418	1.12439
0.22505	2.79143	1.10946
0.22545	2.7983	1.09451
0.22587	2.80479	1.07954
0.22628	2.81091	1.06458
0.22669	2.81667	1.04963
0.22711	2.82206	1.03471
0.22752	2.82709	1.01982
0.22794	2.83178	1.00498
0.22836	2.83612	0.99019
0.22878	2.84013	0.97548
0.22921	2.84381	0.96084
0.22963	2.84716	0.94628
0.23006	2.85021	0.93182
0.23048	2.85294	0.91746
0.23091	2.85538	0.90321
0.23134	2.85753	0.88908
0.23178	2.85939	0.87507
0.23221	2.86099	0.86119
0.23265	2.86231	0.84744
0.23308	2.86338	0.83383
0.23352	2.86421	0.82037
0.23396	2.86479	0.80705
0.2344	2.86514	0.79388
0.23485	2.86526	0.78087
0.23529	2.86518	0.76802
0.23574	2.86488	0.75533
0.23619	2.86438	0.7428
0.23664	2.86369	0.73044
0.23709	2.86282	0.71824
0.23755	2.86177	0.70621
0.238	2.86055	0.69435
0.23846	2.85917	0.68266
0.23892	2.85764	0.67114
0.23938	2.85596	0.65979
0.23985	2.85413	0.64861
0.24031	2.85218	0.6376
0.24078	2.85009	0.62676
0.24125	2.84788	0.61609
0.24172	2.84555	0.60559
0.24219	2.84312	0.59525
0.24266	2.84058	0.58509
0.24314	2.83794	0.57509
0.24361	2.83521	0.56525
0.24409	2.83239	0.55558
0.24458	2.82948	0.54607
0.24506	2.8265	0.53672
0.24554	2.82344	0.52753
0.24603	2.82032	0.51849
0.24652	2.81712	0.50961
0.24701	2.81387	0.50089
0.2475	2.81056	0.49231
0.248	2.80719	0.48388
0.2485	2.80378	0.4756
0.249	2.80032	0.46747
0.2495	2.79681	0.45948
0.25	2.79327	0.45163
0.25051	2.78969	0.44392
0.25101	2.78608	0.43635
0.25152	2.78243	0.42891
0.25203	2.77876	0.4216
0.25255	2.77506	0.41442
0.25306	2.77134	0.40738
0.25358	2.7676	0.40045
0.2541	2.76384	0.39366
0.25462	2.76006	0.38698
0.25514	2.75627	0.38042
0.25567	2.75247	0.37399
0.2562	2.74866	0.36766
0.25673	2.74484	0.36145
0.25726	2.74101	0.35536
0.2578	2.73718	0.34937
0.25833	2.73335	0.34349
0.25887	2.72951	0.33771
0.25941	2.72567	0.33204
0.25996	2.72184	0.32647
0.2605	2.718	0.321
0.26105	2.71417	0.31562
0.2616	2.71034	0.31035
0.26216	2.70652	0.30517
0.26271	2.70271	0.30007
0.26327	2.6989	0.29508
0.26383	2.6951	0.29016
0.26439	2.69131	0.28534
0.26496	2.68753	0.2806
0.26552	2.68377	0.27595
0.26609	2.68001	0.27138
0.26667	2.67627	0.26688
0.26724	2.67253	0.26247
0.26782	2.66882	0.25813
0.2684	2.66511	0.25388
0.26898	2.66142	0.24969
0.26957	2.65775	0.24558
0.27015	2.65409	0.24154
0.27074	2.65045	0.23757
0.27133	2.64683	0.23367
0.27193	2.64322	0.22983
0.27253	2.63963	0.22606
0.27313	2.63605	0.22236
0.27373	2.6325	0.21872
0.27434	2.62896	0.21514
0.27494	2.62544	0.21163
0.27556	2.62194	0.20817
0.27617	2.61846	0.20477
0.27679	2.615	0.20143
0.2774	2.61155	0.19815
0.27803	2.60813	0.19492
0.27865	2.60472	0.19175
0.27928	2.60134	0.18862
0.27991	2.59798	0.18556
0.28054	2.59463	0.18254
0.28118	2.59131	0.17957
0.28182	2.588	0.17665
0.28246	2.58472	0.17378
0.28311	2.58145	0.17096
0.28375	2.57821	0.16818
0.2844	2.57498	0.16545
0.28506	2.57178	0.16277
0.28571	2.5686	0.16013
0.28637	2.56543	0.15753
0.28704	2.56229	0.15497
0.2877	2.55917	0.15245
0.28837	2.55607	0.14998
0.28904	2.55298	0.14754
0.28972	2.54992	0.14515
0.2904	2.54688	0.14279
0.29108	2.54386	0.14047
0.29176	2.54086	0.13819
0.29245	2.53787	0.13594
0.29314	2.53491	0.13373
0.29384	2.53197	0.13155
0.29454	2.52905	0.12941
0.29524	2.52615	0.1273
0.29594	2.52326	0.12522
0.29665	2.5204	0.12318
0.29736	2.51756	0.12117
0.29808	2.51473	0.11919
0.2988	2.51193	0.11724
0.29952	2.50914	0.11532
0.30024	2.50637	0.11343
0.30097	2.50362	0.11157
0.3017	2.50089	0.10974
0.30244	2.49818	0.10793
0.30318	2.49549	0.10616
0.30392	2.49282	0.10441
0.30467	2.49016	0.10268
0.30542	2.48753	0.10099
0.30617	2.48491	0.09931
0.30693	2.48231	0.09767
0.30769	2.47972	0.09605
0.30846	2.47716	0.09445
0.30923	2.47461	0.09288
0.31	2.47208	0.09133
0.31078	2.46957	0.0898
0.31156	2.46707	0.0883
0.31234	2.4646	0.08681
0.31313	2.46214	0.08535
0.31392	2.45969	0.08392
0.31472	2.45726	0.0825
0.31552	2.45485	0.0811
0.31633	2.45246	0.07973
0.31714	2.45008	0.07837
0.31795	2.44772	0.07704
0.31877	2.44538	0.07572
0.31959	2.44305	0.07442
0.32041	2.44074	0.07315
0.32124	2.43844	0.07189
0.32208	2.43616	0.07064
0.32292	2.43389	0.06942
0.32376	2.43164	0.06822
0.32461	2.42941	0.06703
0.32546	2.42719	0.06586
0.32632	2.42498	0.0647
0.32718	2.42279	0.06356
0.32804	2.42062	0.06244
0.32891	2.41846	0.06134
0.32979	2.41631	0.06025
0.33067	2.41418	0.05917
0.33155	2.41207	0.05811
0.33244	2.40996	0.05707
0.33333	2.40788	0.05604
0.33423	2.4058	0.05503
0.33514	2.40374	0.05403
0.33604	2.4017	0.05304
0.33696	2.39966	0.05207
0.33787	2.39764	0.05111
0.3388	2.39564	0.05017
0.33973	2.39365	0.04924
0.34066	2.39167	0.04832
0.3416	2.3897	0.04742
0.34254	2.38775	0.04652
0.34349	2.38581	0.04565
0.34444	2.38388	0.04478
0.3454	2.38197	0.04392
0.34637	2.38006	0.04308
0.34734	2.37818	0.04225
0.34831	2.3763	0.04143
0.3493	2.37443	0.04062
0.35028	2.37258	0.03983
0.35127	2.37074	0.03904
0.35227	2.36891	0.03827
0.35328	2.3671	0.03751
0.35429	2.36529	0.03676
0.3553	2.3635	0.03602
0.35632	2.36172	0.03529
0.35735	2.35995	0.03457
0.35838	2.35819	0.03386
0.35942	2.35644	0.03316
0.36047	2.3547	0.03247
0.36152	2.35298	0.03179
0.36257	2.35126	0.03112
0.36364	2.34956	0.03046
0.36471	2.34787	0.02981
0.36578	2.34619	0.02916
0.36686	2.34452	0.02853
0.36795	2.34286	0.02791
0.36905	2.34121	0.02729
0.37015	2.33957	0.02669
0.37126	2.33794	0.02609
0.37237	2.33632	0.0255
0.37349	2.33471	0.02493
0.37462	2.33311	0.02435
0.37576	2.33152	0.02379
0.3769	2.32995	0.02324
0.37805	2.32838	0.02269
0.3792	2.32682	0.02216
0.38037	2.32527	0.02163
0.38154	2.32373	0.0211
0.38272	2.3222	0.02059
0.3839	2.32068	0.02009
0.38509	2.31917	0.01959
0.38629	2.31767	0.0191
0.3875	2.31617	0.01861
0.38871	2.31469	0.01814
0.38994	2.31322	0.01767
0.39117	2.31175	0.01721
0.39241	2.31029	0.01676
0.39365	2.30885	0.01631
0.3949	2.30741	0.01587
0.39617	2.30598	0.01544
0.39744	2.30456	0.01501
0.39871	2.30315	0.01459
0.4	2.30174	0.01418
0.40129	2.30035	0.01378
0.4026	2.29896	0.01338
0.40391	2.29758	0.01299
0.40523	2.29621	0.0126
0.40656	2.29485	0.01223
0.40789	2.2935	0.01185
0.40924	2.29215	0.01149
0.4106	2.29082	0.01113
0.41196	2.28949	0.01078
0.41333	2.28817	0.01043
0.41472	2.28685	0.01009
0.41611	2.28555	0.00976
0.41751	2.28425	0.00943
0.41892	2.28296	0.00911
0.42034	2.28168	0.00879
0.42177	2.28041	0.00848
0.42321	2.27914	0.00818
0.42466	2.27789	0.00788
0.42612	2.27664	0.00759
0.42759	2.27539	0.0073
0.42907	2.27416	0.00702
0.43056	2.27293	0.00675
0.43206	2.27171	0.00648
0.43357	2.2705	0.00622
0.43509	2.26929	0.00596
0.43662	2.2681	0.00571
0.43816	2.26691	0.00546
0.43972	2.26572	0.00522
0.44128	2.26455	0.00499
0.44286	2.26338	0.00476
0.44444	2.26222	0.00454
0.44604	2.26106	0.00432
0.44765	2.25992	0.00411
0.44928	2.25878	0.0039
0.45091	2.25765	0.0037
0.45255	2.25652	0.0035
0.45421	2.2554	0.00331
0.45588	2.25429	0.00313
0.45756	2.25319	0.00295
0.45926	2.25209	0.00277
0.46097	2.251	0.0026
0.46269	2.24992	0.00244
0.46442	2.24885	0.00228
0.46617	2.24778	0.00213
0.46792	2.24672	0.00198
0.4697	2.24567	0.00184
0.47148	2.24462	0.0017
0.47328	2.24358	0.00157
0.4751	2.24255	0.00144
0.47692	2.24152	0.00132
0.47876	2.24051	0.00121
0.48062	2.23949	0.0011
0.48249	2.23849	0.000991746
0.48438	2.2375	0.000891701
0.48627	2.23651	0.000796939
0.48819	2.23553	0.000707459
0.49012	2.23455	0.000623266
0.49206	2.23359	0.000544364
0.49402	2.23263	0.000470758
0.496	2.23168	0.000402453
0.49799	2.23074	0.000339459
0.5	2.2298	0.000281782
0.50202	2.22888	0.000229432
0.50407	2.22796	0.00018242
0.50612	2.22705	0.000140758
0.5082	2.22615	0.000104457
0.51029	2.22525	7.35326e-05
0.5124	2.22437	4.79985e-05
0.51452	2.2235	2.7871e-05
0.51667	2.22263	1.3167e-05
0.51883	2.22178	3.9047e-06
0.52101	2.22093	1.03301e-07
0.52321	2.22011	0.0
0.52542	2.21929	0.0
0.52766	2.21849	0.0
0.52991	2.21769	0.0
0.53219	2.21691	0.0
0.53448	2.21613	0.0
0.5368	2.21536	0.0
0.53913	2.21461	0.0
0.54148	2.21385	0.0
0.54386	2.21311	0.0
0.54626	2.21238	0.0
0.54867	2.21165	0.0
0.55111	2.21093	0.0
0.55357	2.21022	0.0
0.55605	2.20951	0.0
0.55856	2.20881	0.0
0.56109	2.20812	0.0
0.56364	2.20743	0.0
0.56621	2.20675	0.0
0.56881	2.20608	0.0
0.57143	2.20542	0.0
0.57407	2.20476	0.0
0.57674	2.2041	0.0
0.57944	2.20345	0.0
0.58216	2.20281	0.0
0.58491	2.20218	0.0
0.58768	2.20155	0.0
0.59048	2.20092	0.0
0.5933	2.2003	0.0
0.59615	2.19969	0.0
0.59903	2.19908	0.0
0.60194	2.19848	0.0
0.60488	2.19789	0.0
0.60784	2.19729	0.0
0.61084	2.19671	0.0
0.61386	2.19613	0.0
0.61692	2.19555	0.0
0.62	2.19498	0.0
0.62312	2.19442	0.0
0.62626	2.19386	0.0
0.62944	2.1933	0.0
0.63265	2.19275	0.0
0.6359	2.1922	0.0
0.63918	2.19166	0.0
0.64249	2.19112	0.0
0.64583	2.19059	0.0
0.64921	2.19007	0.0
0.65263	2.18954	0.0
0.65608	2.18902	0.0
0.65957	2.18851	0.0
0.6631	2.188	0.0
0.66667	2.1875	0.0
0.67027	2.187	0.0
0.67391	2.1865	0.0
0.6776	2.18601	0.0
0.68132	2.18552	0.0
0.68508	2.18504	0.0
0.68889	2.18456	0.0
0.69274	2.18408	0.0
0.69663	2.18361	0.0
0.70056	2.18315	0.0
0.70455	2.18268	0.0
0.70857	2.18222	0.0
0.71264	2.18177	0.0
0.71676	2.18132	0.0
0.72093	2.18087	0.0
0.72515	2.18043	0.0
0.72941	2.17999	0.0
0.73373	2.17955	0.0
0.7381	2.17912	0.0
0.74251	2.17869	0.0
0.74699	2.17827	0.0
0.75152	2.17785	0.0
0.7561	2.17743	0.0
0.76074	2.17702	0.0
0.76543	2.17661	0.0
0.77019	2.1762	0.0
0.775	2.1758	0.0
0.77987	2.1754	0.0
0.78481	2.17501	0.0
0.78981	2.17461	0.0
0.79487	2.17423	0.0
0.8	2.17384	0.0
0.80519	2.17346	0.0
0.81046	2.17308	0.0
0.81579	2.17271	0.0
0.82119	2.17234	0.0
0.82667	2.17197	0.0
0.83221	2.1716	0.0
0.83784	2.17124	0.0
0.84354	2.17088	0.0
0.84932	2.17053	0.0
0.85517	2.17018	0.0
0.86111	2.16983	0.0
0.86713	2.16948	0.0
0.87324	2.16914	0.0
0.87943	2.1688	0.0
0.88571	2.16846	0.0
0.89209	2.16813	0.0
0.89855	2.1678	0.0
0.90511	2.16748	0.0
0.91176	2.16715	0.0
0.91852	2.16683	0.0
0.92537	2.16651	0.0
0.93233	2.1662	0.0
0.93939	2.16589	0.0
0.94656	2.16558	0.0
0.95385	2.16527	0.0
0.96124	2.16497	0.0
0.96875	2.16467	0.0
0.97638	2.16437	0.0
0.98413	2.16408	0.0
0.992	2.16379	0.0
1.0	2.1635	0.0
1.00813	2.16321	0.0
1.01639	2.16293	0.0
1.02479	2.16265	0.0
1.03333	2.16237	0.0
1.04202	2.1621	0.0
1.05085	2.16183	0.0
1.05983	2.16156	0.0
1.06897	2.16129	0.0
1.07826	2.16103	0.0
1.08772	2.16077	0.0
1.09735	2.16051	0.0
1.10714	2.16026	0.0
1.11712	2.16	0.0
1.12727	2.15976	0.0
1.13761	2.15951	0.0
1.14815	2.15926	0.0
1.15888	2.15902	0.0
1.16981	2.15878	0.0
1.18095	2.15855	0.0
1.19231	2.15831	0.0
1.20388	2.15808	0.0
1.21569	2.15785	0.0
1.22772	2.15763	0.0
1.24	2.1574	0.0

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: —

Plot