Optical constants

Refractive index of ThF₄ (Thorium tetrafluoride)

Heitmann and Ritter 1976: n 0.26–0.76 µm

Data: formula 2
Range: 0.26–0.76 µm
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.51246
Extinction coefficient k: 0

Permittivity ε₁: 2.28753
Permittivity ε₂: 0

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

Abbe number V_d: 57.998
Chromatic dispersion dn/dλ: -0.0452873 µm⁻¹

Group index n_g: 1.53907
Group velocity dispersion: 86.0444 fs²/mm

Dispersion parameter D: -469.418 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

# ThF4 (Thorium tetrafluoride): Heitmann and Ritter 1976: n 0.26–0.76 µm
thf4 = ls.fetch_refractiveindex("main", "ThF4", "Heitmann", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(thf4.range_nm)  # (260, 760) nm
eps = thf4.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_bb3319c848b5/lightsmith"
thf4 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(thf4.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (thf4/heitmann-ritter-1976).

# ... load thf4 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=thf4)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=400, stop_nm=760, 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_bb3319c848b5/lightsmith?model=drude_lorentz"
thf4_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 = \frac{1.2485 λ^{2}}{λ^{2} - 0.010466}

Valid from 0.26 to 0.76 µm.

Coefficients as stored

C_i	Value
C1	0.0
C2	1.2485
C3	0.010466

Comments and conditions

ThF₄ film on quartz glass

References

W. Heitmann and E. Ritter. Production and properties of vacuum evaporated films of thorium fluoride. Appl. Opt. 7, 307-309 (1968)
(Digitization of graphical data and fitting with the Sellmeier dispersion formula: refractiveindex.info)

doi:10.1364/ao.7.000307 Production and Properties of Vacuum Evaporated Films of Thorium Fluoride, Applied Optics (1968)

Cite

W. Heitmann and E. Ritter. Production and Properties of Vacuum Evaporated Films of Thorium Fluoride. Applied Optics, 7, 307 (1968), doi:10.1364/ao.7.000307; (Digitization of graphical data and fitting with the Sellmeier dispersion formula: refractiveindex.info); Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)

Data

Computed on 400 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

ThF4 (Thorium tetrafluoride), Heitmann and Ritter 1976: n 0.26–0.76 µm: n and k versus wavelength
λ (µm)	n
0.26	1.573914
0.2607	1.573453
0.261402	1.572996
0.262105	1.572542
0.262811	1.572091
0.263518	1.571643
0.264228	1.571198
0.264939	1.570757
0.265652	1.570318
0.266367	1.569883
0.267084	1.56945
0.267803	1.569021
0.268524	1.568594
0.269247	1.568171
0.269972	1.56775
0.270699	1.567332
0.271427	1.566918
0.272158	1.566506
0.272891	1.566096
0.273625	1.56569
0.274362	1.565287
0.2751	1.564886
0.275841	1.564488
0.276584	1.564092
0.277328	1.5637
0.278075	1.56331
0.278823	1.562922
0.279574	1.562537
0.280326	1.562155
0.281081	1.561776
0.281838	1.561399
0.282596	1.561024
0.283357	1.560652
0.28412	1.560283
0.284885	1.559916
0.285652	1.559552
0.28642	1.55919
0.287191	1.55883
0.287965	1.558473
0.28874	1.558118
0.289517	1.557765
0.290296	1.557415
0.291078	1.557068
0.291861	1.556722
0.292647	1.556379
0.293435	1.556038
0.294225	1.555699
0.295017	1.555363
0.295811	1.555029
0.296607	1.554697
0.297406	1.554367
0.298206	1.55404
0.299009	1.553714
0.299814	1.553391
0.300621	1.55307
0.30143	1.55275
0.302242	1.552433
0.303055	1.552119
0.303871	1.551806
0.304689	1.551495
0.305509	1.551186
0.306332	1.550879
0.307156	1.550575
0.307983	1.550272
0.308812	1.549971
0.309644	1.549672
0.310477	1.549375
0.311313	1.54908
0.312151	1.548787
0.312991	1.548496
0.313834	1.548206
0.314679	1.547919
0.315526	1.547633
0.316375	1.54735
0.317227	1.547068
0.318081	1.546787
0.318937	1.546509
0.319795	1.546233
0.320656	1.545958
0.32152	1.545685
0.322385	1.545413
0.323253	1.545144
0.324123	1.544876
0.324996	1.54461
0.32587	1.544345
0.326748	1.544083
0.327627	1.543822
0.328509	1.543562
0.329394	1.543304
0.33028	1.543048
0.331169	1.542794
0.332061	1.542541
0.332955	1.542289
0.333851	1.54204
0.33475	1.541792
0.335651	1.541545
0.336554	1.5413
0.33746	1.541056
0.338369	1.540814
0.33928	1.540574
0.340193	1.540335
0.341109	1.540098
0.342027	1.539862
0.342948	1.539627
0.343871	1.539394
0.344797	1.539163
0.345725	1.538933
0.346655	1.538704
0.347589	1.538477
0.348524	1.538251
0.349462	1.538026
0.350403	1.537803
0.351346	1.537582
0.352292	1.537361
0.353241	1.537143
0.354191	1.536925
0.355145	1.536709
0.356101	1.536494
0.35706	1.53628
0.358021	1.536068
0.358984	1.535857
0.359951	1.535648
0.36092	1.535439
0.361891	1.535232
0.362866	1.535027
0.363842	1.534822
0.364822	1.534619
0.365804	1.534417
0.366789	1.534216
0.367776	1.534017
0.368766	1.533819
0.369759	1.533622
0.370754	1.533426
0.371752	1.533231
0.372753	1.533038
0.373756	1.532845
0.374762	1.532654
0.375771	1.532464
0.376783	1.532275
0.377797	1.532088
0.378814	1.531901
0.379834	1.531716
0.380856	1.531532
0.381882	1.531349
0.38291	1.531167
0.38394	1.530986
0.384974	1.530806
0.38601	1.530627
0.387049	1.530449
0.388091	1.530273
0.389136	1.530097
0.390183	1.529923
0.391234	1.52975
0.392287	1.529577
0.393343	1.529406
0.394402	1.529236
0.395463	1.529067
0.396528	1.528898
0.397595	1.528731
0.398666	1.528565
0.399739	1.5284
0.400815	1.528235
0.401894	1.528072
0.402976	1.52791
0.404061	1.527749
0.405148	1.527588
0.406239	1.527429
0.407333	1.527271
0.408429	1.527113
0.409528	1.526957
0.410631	1.526801
0.411736	1.526647
0.412845	1.526493
0.413956	1.52634
0.41507	1.526188
0.416188	1.526037
0.417308	1.525887
0.418431	1.525738
0.419558	1.52559
0.420687	1.525442
0.42182	1.525296
0.422955	1.52515
0.424094	1.525005
0.425235	1.524861
0.42638	1.524718
0.427528	1.524576
0.428679	1.524434
0.429833	1.524294
0.43099	1.524154
0.43215	1.524015
0.433313	1.523877
0.43448	1.52374
0.435649	1.523603
0.436822	1.523468
0.437998	1.523333
0.439177	1.523199
0.440359	1.523065
0.441545	1.522933
0.442733	1.522801
0.443925	1.52267
0.44512	1.52254
0.446318	1.522411
0.44752	1.522282
0.448725	1.522154
0.449932	1.522027
0.451144	1.5219
0.452358	1.521775
0.453576	1.52165
0.454797	1.521526
0.456021	1.521402
0.457249	1.521279
0.45848	1.521157
0.459714	1.521036
0.460951	1.520915
0.462192	1.520796
0.463436	1.520676
0.464684	1.520558
0.465935	1.52044
0.467189	1.520323
0.468447	1.520206
0.469708	1.520091
0.470972	1.519976
0.47224	1.519861
0.473511	1.519747
0.474786	1.519634
0.476064	1.519522
0.477345	1.51941
0.47863	1.519299
0.479919	1.519188
0.481211	1.519079
0.482506	1.518969
0.483805	1.518861
0.485107	1.518753
0.486413	1.518645
0.487723	1.518539
0.489036	1.518433
0.490352	1.518327
0.491672	1.518222
0.492996	1.518118
0.494323	1.518014
0.495653	1.517911
0.496988	1.517809
0.498325	1.517707
0.499667	1.517606
0.501012	1.517505
0.502361	1.517405
0.503713	1.517305
0.505069	1.517206
0.506429	1.517108
0.507792	1.51701
0.509159	1.516913
0.510529	1.516816
0.511904	1.51672
0.513282	1.516624
0.514663	1.516529
0.516049	1.516435
0.517438	1.516341
0.518831	1.516247
0.520228	1.516154
0.521628	1.516062
0.523032	1.51597
0.52444	1.515879
0.525852	1.515788
0.527267	1.515698
0.528687	1.515608
0.53011	1.515519
0.531537	1.51543
0.532968	1.515342
0.534403	1.515254
0.535841	1.515167
0.537284	1.51508
0.53873	1.514994
0.54018	1.514908
0.541634	1.514823
0.543092	1.514738
0.544554	1.514654
0.54602	1.51457
0.54749	1.514487
0.548964	1.514404
0.550442	1.514322
0.551923	1.51424
0.553409	1.514158
0.554899	1.514077
0.556393	1.513997
0.55789	1.513917
0.559392	1.513837
0.560898	1.513758
0.562408	1.513679
0.563922	1.513601
0.56544	1.513523
0.566962	1.513446
0.568488	1.513369
0.570019	1.513292
0.571553	1.513216
0.573092	1.513141
0.574634	1.513065
0.576181	1.512991
0.577732	1.512916
0.579287	1.512842
0.580847	1.512769
0.58241	1.512696
0.583978	1.512623
0.58555	1.512551
0.587127	1.512479
0.588707	1.512408
0.590292	1.512336
0.591881	1.512266
0.593474	1.512196
0.595072	1.512126
0.596674	1.512056
0.59828	1.511987
0.59989	1.511919
0.601505	1.51185
0.603124	1.511782
0.604748	1.511715
0.606376	1.511648
0.608008	1.511581
0.609645	1.511514
0.611286	1.511448
0.612932	1.511383
0.614582	1.511318
0.616236	1.511253
0.617895	1.511188
0.619558	1.511124
0.621226	1.51106
0.622898	1.510997
0.624575	1.510933
0.626256	1.510871
0.627942	1.510808
0.629633	1.510746
0.631328	1.510685
0.633027	1.510623
0.634731	1.510562
0.63644	1.510502
0.638153	1.510441
0.639871	1.510381
0.641593	1.510322
0.64332	1.510262
0.645052	1.510203
0.646789	1.510145
0.64853	1.510086
0.650276	1.510028
0.652026	1.509971
0.653781	1.509913
0.655541	1.509856
0.657306	1.509799
0.659075	1.509743
0.66085	1.509687
0.662628	1.509631
0.664412	1.509576
0.666201	1.509521
0.667994	1.509466
0.669792	1.509411
0.671595	1.509357
0.673403	1.509303
0.675216	1.509249
0.677034	1.509196
0.678856	1.509143
0.680684	1.50909
0.682516	1.509038
0.684353	1.508986
0.686195	1.508934
0.688043	1.508882
0.689895	1.508831
0.691752	1.50878
0.693614	1.508729
0.695481	1.508679
0.697353	1.508629
0.699231	1.508579
0.701113	1.508529
0.703	1.50848
0.704893	1.508431
0.70679	1.508382
0.708693	1.508334
0.710601	1.508285
0.712514	1.508237
0.714432	1.50819
0.716355	1.508142
0.718283	1.508095
0.720217	1.508048
0.722156	1.508002
0.724099	1.507955
0.726049	1.507909
0.728003	1.507863
0.729963	1.507818
0.731928	1.507772
0.733898	1.507727
0.735874	1.507682
0.737855	1.507638
0.739841	1.507593
0.741833	1.507549
0.74383	1.507505
0.745832	1.507462
0.74784	1.507418
0.749853	1.507375
0.751871	1.507332
0.753895	1.50729
0.755925	1.507247
0.75796	1.507205
0.76	1.507163

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: —

ThF₄ (Thorium tetrafluoride): all datasets

Heitmann and Ritter 1976: n 0.26–0.76 µm n 0.26–0.76 µm default

About ThF4 (Thorium tetrafluoride)

Thorium tetrafluoride (ThF₄) is a white crystalline solid and is one of the principal halide compounds of thorium. Due to its high melting point and low refractive index, it has been investigated as a potential material for optical windows, especially in the infrared range. ThF₄ has been found to possess favorable transmission properties in the mid and far-infrared spectrum, making it suitable for some infrared optics applications. Furthermore, as with many thorium compounds, it is radioactive because thorium is predominantly found as the isotope Th-232, which decays over time. Handling and use of ThF₄ therefore require precautions to protect against radiation exposure. The compound also serves as an intermediate in the processing of thorium from its ores and can be a precursor to other thorium compounds in various chemical processes.

More about ThF4 (Thorium tetrafluoride) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/ThF4/nk/Heitmann.yml
ID: ds_bb3319c848b5
API: /v1/datasets/ds_bb3319c848b5

Plot