Optical constants

Refractive index of SrF₂ (Strontium fluoride)

Feldman et al. 1978: n 0.21–11.5 µm

Data: formula 1
Range: 0.21–11.5 µm
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.43806
Extinction coefficient k: 0

Permittivity ε₁: 2.06801
Permittivity ε₂: 0

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

Abbe number V_d: 93.081
Chromatic dispersion dn/dλ: -0.0242683 µm⁻¹

Group index n_g: 1.45232
Group velocity dispersion: 43.7954 fs²/mm

Dispersion parameter D: -238.927 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

# SrF2 (Strontium fluoride): Feldman et al. 1978: n 0.21–11.5 µm
srf2 = ls.fetch_refractiveindex("main", "SrF2", "Feldman", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(srf2.range_nm)  # (210, 11500) nm
eps = srf2.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_d774174b1451/lightsmith"
srf2 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(srf2.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (srf2/feldman-1978).

# ... load srf2 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=srf2)],
    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"]).

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_d774174b1451/lightsmith?model=drude_lorentz"
srf2_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 (formula 1), λ in µm

n^{2} - 1 = \frac{0.67805894 λ^{2}}{λ^{2} - {0.05628989}^{2}} + \frac{0.37140533 λ^{2}}{λ^{2} - {0.10801027}^{2}} + \frac{3.3485284 λ^{2}}{λ^{2} - {39.906666}^{2}}

Valid from 0.21 to 11.5 µm.

Coefficients as stored

C_i	Value
C1	0.0
C2	0.67805894
C3	0.05628989
C4	0.37140533
C5	0.10801027
C6	3.3485284
C7	39.906666

Comments and conditions

20 °C

References

A. Feldman, D. Horowitz, R. Waxier and M. Dodge. Optical materials characterization final technical report, February 1, 1978.

Cite

A. Feldman, D. Horowitz, R. Waxier and M. Dodge. Optical materials characterization final technical report, February 1, 1978.; 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

SrF2 (Strontium fluoride), Feldman et al. 1978: n 0.21–11.5 µm: n and k versus wavelength
λ (µm)	n
0.21	1.495143
0.212117	1.493568
0.214256	1.492041
0.216417	1.490559
0.218599	1.48912
0.220803	1.487723
0.223029	1.486367
0.225278	1.485049
0.22755	1.483769
0.229844	1.482525
0.232161	1.481316
0.234502	1.48014
0.236867	1.478997
0.239255	1.477885
0.241668	1.476803
0.244104	1.47575
0.246566	1.474725
0.249052	1.473728
0.251563	1.472757
0.2541	1.471811
0.256662	1.47089
0.25925	1.469993
0.261864	1.469119
0.264504	1.468267
0.267171	1.467437
0.269865	1.466628
0.272586	1.46584
0.275335	1.465071
0.278111	1.464321
0.280915	1.46359
0.283747	1.462877
0.286608	1.462181
0.289498	1.461503
0.292417	1.460841
0.295366	1.460195
0.298344	1.459564
0.301352	1.458949
0.304391	1.458348
0.30746	1.457762
0.31056	1.457189
0.313692	1.45663
0.316855	1.456085
0.320049	1.455552
0.323276	1.455031
0.326536	1.454522
0.329829	1.454026
0.333154	1.45354
0.336513	1.453066
0.339907	1.452603
0.343334	1.45215
0.346796	1.451708
0.350292	1.451276
0.353825	1.450853
0.357392	1.45044
0.360996	1.450036
0.364636	1.449642
0.368312	1.449256
0.372026	1.448878
0.375777	1.448509
0.379566	1.448148
0.383393	1.447796
0.387259	1.447451
0.391164	1.447113
0.395108	1.446783
0.399092	1.44646
0.403116	1.446144
0.407181	1.445835
0.411286	1.445533
0.415433	1.445237
0.419622	1.444947
0.423853	1.444664
0.428127	1.444387
0.432444	1.444115
0.436804	1.44385
0.441209	1.44359
0.445657	1.443335
0.450151	1.443086
0.45469	1.442843
0.459274	1.442604
0.463905	1.44237
0.468583	1.442141
0.473308	1.441917
0.47808	1.441698
0.482901	1.441483
0.48777	1.441273
0.492688	1.441067
0.497656	1.440865
0.502674	1.440667
0.507742	1.440473
0.512862	1.440284
0.518033	1.440098
0.523256	1.439916
0.528532	1.439737
0.533861	1.439562
0.539244	1.439391
0.544682	1.439223
0.550174	1.439058
0.555721	1.438897
0.561325	1.438739
0.566984	1.438584
0.572701	1.438432
0.578476	1.438283
0.584309	1.438137
0.5902	1.437994
0.596151	1.437853
0.602162	1.437716
0.608234	1.43758
0.614367	1.437448
0.620562	1.437318
0.626819	1.43719
0.633139	1.437065
0.639523	1.436942
0.645971	1.436822
0.652485	1.436704
0.659064	1.436588
0.665709	1.436474
0.672422	1.436362
0.679202	1.436252
0.68605	1.436144
0.692968	1.436038
0.699955	1.435934
0.707012	1.435832
0.714141	1.435732
0.721342	1.435633
0.728615	1.435536
0.735962	1.435441
0.743383	1.435347
0.750878	1.435255
0.75845	1.435165
0.766097	1.435076
0.773822	1.434988
0.781624	1.434902
0.789505	1.434818
0.797466	1.434734
0.805507	1.434652
0.813629	1.434572
0.821833	1.434492
0.830119	1.434414
0.838489	1.434337
0.846944	1.434261
0.855484	1.434186
0.86411	1.434112
0.872823	1.43404
0.881623	1.433968
0.890513	1.433897
0.899492	1.433828
0.908561	1.433759
0.917723	1.433691
0.926976	1.433624
0.936323	1.433558
0.945764	1.433493
0.9553	1.433428
0.964932	1.433364
0.974662	1.433301
0.984489	1.433239
0.994416	1.433177
1.00444	1.433116
1.01457	1.433056
1.0248	1.432996
1.03513	1.432937
1.04557	1.432879
1.05611	1.432821
1.06676	1.432763
1.07752	1.432706
1.08838	1.432649
1.09936	1.432593
1.11044	1.432538
1.12164	1.432482
1.13295	1.432427
1.14437	1.432373
1.15591	1.432318
1.16757	1.432264
1.17934	1.432211
1.19123	1.432157
1.20324	1.432104
1.21537	1.432051
1.22763	1.431998
1.24001	1.431945
1.25251	1.431893
1.26514	1.431841
1.2779	1.431788
1.29078	1.431736
1.3038	1.431684
1.31694	1.431632
1.33022	1.43158
1.34363	1.431528
1.35718	1.431476
1.37087	1.431424
1.38469	1.431371
1.39865	1.431319
1.41275	1.431267
1.427	1.431214
1.44139	1.431161
1.45592	1.431109
1.4706	1.431056
1.48543	1.431002
1.50041	1.430949
1.51553	1.430895
1.53082	1.430841
1.54625	1.430787
1.56184	1.430732
1.57759	1.430677
1.5935	1.430622
1.60956	1.430566
1.62579	1.43051
1.64219	1.430453
1.65875	1.430396
1.67547	1.430338
1.69236	1.43028
1.70943	1.430221
1.72666	1.430162
1.74407	1.430103
1.76166	1.430042
1.77942	1.429981
1.79737	1.429919
1.81549	1.429857
1.83379	1.429794
1.85228	1.42973
1.87096	1.429666
1.88983	1.4296
1.90888	1.429534
1.92813	1.429467
1.94757	1.429399
1.96721	1.429331
1.98704	1.429261
2.00708	1.42919
2.02732	1.429119
2.04776	1.429046
2.06841	1.428973
2.08926	1.428898
2.11033	1.428822
2.13161	1.428745
2.1531	1.428667
2.17481	1.428588
2.19674	1.428507
2.21889	1.428425
2.24126	1.428342
2.26386	1.428258
2.28669	1.428172
2.30974	1.428085
2.33303	1.427996
2.35656	1.427906
2.38032	1.427814
2.40432	1.427721
2.42856	1.427627
2.45305	1.42753
2.47778	1.427432
2.50277	1.427332
2.528	1.427231
2.55349	1.427128
2.57924	1.427023
2.60525	1.426916
2.63151	1.426807
2.65805	1.426696
2.68485	1.426583
2.71192	1.426468
2.73927	1.426351
2.76689	1.426232
2.79478	1.42611
2.82296	1.425987
2.85143	1.425861
2.88018	1.425732
2.90922	1.425602
2.93855	1.425468
2.96818	1.425333
2.99811	1.425194
3.02834	1.425053
3.05888	1.42491
3.08972	1.424763
3.12087	1.424614
3.15234	1.424462
3.18413	1.424307
3.21623	1.424149
3.24866	1.423987
3.28142	1.423823
3.31451	1.423655
3.34793	1.423485
3.38168	1.42331
3.41578	1.423133
3.45022	1.422951
3.48501	1.422767
3.52015	1.422578
3.55565	1.422386
3.5915	1.42219
3.62771	1.42199
3.66429	1.421786
3.70124	1.421578
3.73856	1.421366
3.77625	1.421149
3.81433	1.420928
3.85279	1.420703
3.89164	1.420473
3.93088	1.420238
3.97051	1.419999
4.01055	1.419754
4.05098	1.419505
4.09183	1.419251
4.13309	1.418991
4.17476	1.418726
4.21686	1.418456
4.25938	1.41818
4.30232	1.417899
4.3457	1.417612
4.38952	1.417318
4.43378	1.417019
4.47849	1.416714
4.52365	1.416402
4.56926	1.416084
4.61533	1.415759
4.66187	1.415427
4.70887	1.415089
4.75635	1.414743
4.80431	1.41439
4.85275	1.41403
4.90168	1.413662
4.95111	1.413287
5.00103	1.412904
5.05146	1.412512
5.10239	1.412113
5.15384	1.411705
5.2058	1.411288
5.25829	1.410863
5.31131	1.410429
5.36487	1.409985
5.41896	1.409532
5.4736	1.40907
5.52879	1.408597
5.58454	1.408115
5.64085	1.407622
5.69773	1.407119
5.75518	1.406605
5.81321	1.40608
5.87182	1.405544
5.93103	1.404996
5.99083	1.404436
6.05124	1.403865
6.11225	1.403281
6.17388	1.402684
6.23613	1.402075
6.29901	1.401452
6.36253	1.400816
6.42668	1.400166
6.49148	1.399502
6.55693	1.398824
6.62305	1.39813
6.68983	1.397422
6.75728	1.396698
6.82542	1.395958
6.89424	1.395201
6.96375	1.394428
7.03397	1.393639
7.10489	1.392831
7.17653	1.392006
7.24889	1.391162
7.32198	1.3903
7.39581	1.389418
7.47039	1.388517
7.54571	1.387595
7.62179	1.386653
7.69864	1.385689
7.77627	1.384704
7.85468	1.383697
7.93388	1.382667
8.01388	1.381613
8.09468	1.380536
8.1763	1.379434
8.25874	1.378306
8.34202	1.377153
8.42613	1.375974
8.51109	1.374767
8.59691	1.373532
8.68359	1.372269
8.77115	1.370976
8.85959	1.369653
8.94892	1.3683
9.03915	1.366914
9.13029	1.365496
9.22236	1.364045
9.31535	1.362559
9.40927	1.361038
9.50415	1.359481
9.59998	1.357886
9.69678	1.356253
9.79455	1.354581
9.89331	1.352869
9.99306	1.351115
10.0938	1.349318
10.1956	1.347477
10.2984	1.345591
10.4022	1.343659
10.5071	1.341679
10.6131	1.33965
10.7201	1.33757
10.8282	1.335438
10.9374	1.333252
11.0476	1.331011
11.159	1.328713
11.2716	1.326357
11.3852	1.32394
11.5	1.32146

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: —

SrF₂ (Strontium fluoride): all datasets

About SrF2 (Strontium fluoride)

Strontium fluoride (SrF₂) is an inorganic compound that appears as a white crystalline solid at room temperature. With a high melting point and good thermal stability, it is often used in optical applications due to its notable transparency to ultraviolet and visible wavelengths. Its optical clarity has led to its use in the manufacture of windows and lenses, especially in specialized optical systems. Additionally, SrF₂ is employed as a thin film in the production of optical coatings, thanks to its low refractive index. Moreover, the compound is explored for potential use in fluoride ion batteries due to its high ionic conductivity. In nature, strontium fluoride occurs as the mineral strontianite, though most commercial preparations are synthesized through chemical reactions.

More about SrF2 (Strontium fluoride) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/SrF2/nk/Feldman.yml
ID: ds_d774174b1451
API: /v1/datasets/ds_d774174b1451

Plot