Optical constants

Refractive index of BaF₂ (Barium fluoride)

Malitson 1964: n 0.265–10.3 µm

Data: formula 1
Range: 0.2652–10.35 µm
Temperature: 298 K
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.47448
Extinction coefficient k: 0

Permittivity ε₁: 2.17408
Permittivity ε₂: 0

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

Abbe number V_d: 81.612
Chromatic dispersion dn/dλ: -0.0299086 µm⁻¹

Group index n_g: 1.49205
Group velocity dispersion: 55.0149 fs²/mm

Dispersion parameter D: -300.135 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

# BaF2 (Barium fluoride): Malitson 1964: n 0.265–10.3 µm
baf2 = ls.fetch_refractiveindex("main", "BaF2", "Malitson", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(baf2.range_nm)  # (265.2, 10346) nm
eps = baf2.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_d559449e59cb/lightsmith"
baf2 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(baf2.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (baf2/malitson-1964).

# ... load baf2 as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=baf2)],
    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_d559449e59cb/lightsmith?model=drude_lorentz"
baf2_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{0.643356 λ^{2}}{λ^{2} - {0.057789}^{2}} + \frac{0.506762 λ^{2}}{λ^{2} - {0.10968}^{2}} + \frac{3.8261 λ^{2}}{λ^{2} - {46.3864}^{2}}

Valid from 0.2652 to 10.346 µm.

Coefficients as stored

C_i	Value
C1	0.0
C2	0.643356
C3	0.057789
C4	0.506762
C5	0.10968
C6	3.8261
C7	46.3864

Comments and conditions

25 °C

Conditions

temperature: 298 K

References

I. H. Malitson. Refractive properties of barium fluoride. J. Opt. Soc. Am. 54, 628-630 (1964)

doi:10.1364/josa.54.000628 Refractive Properties of Barium Fluoride*, Journal of the Optical Society of America (1964)

Cite

Irving H. Malitson. Refractive Properties of Barium Fluoride*. Journal of the Optical Society of America, 54, 628 (1964), doi:10.1364/josa.54.000628; 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

BaF2 (Barium fluoride), Malitson 1964: n 0.265–10.3 µm: n and k versus wavelength
λ (µm)	n
0.2652	1.51216
0.267646	1.5112
0.270115	1.510264
0.272607	1.509349
0.275122	1.508455
0.27766	1.507582
0.280221	1.50673
0.282806	1.505897
0.285415	1.505083
0.288048	1.504288
0.290705	1.503511
0.293387	1.502752
0.296094	1.502009
0.298825	1.501284
0.301582	1.500574
0.304364	1.499881
0.307172	1.499202
0.310005	1.498539
0.312865	1.49789
0.315751	1.497256
0.318664	1.496635
0.321604	1.496028
0.32457	1.495434
0.327564	1.494852
0.330586	1.494284
0.333636	1.493727
0.336714	1.493183
0.33982	1.49265
0.342955	1.492128
0.346118	1.491617
0.349311	1.491117
0.352534	1.490628
0.355786	1.490149
0.359068	1.48968
0.36238	1.48922
0.365723	1.48877
0.369097	1.48833
0.372502	1.487898
0.375938	1.487476
0.379406	1.487062
0.382906	1.486657
0.386438	1.48626
0.390003	1.485871
0.393601	1.48549
0.397232	1.485116
0.400896	1.484751
0.404595	1.484392
0.408327	1.484041
0.412094	1.483697
0.415895	1.483359
0.419732	1.483029
0.423604	1.482705
0.427512	1.482388
0.431455	1.482076
0.435435	1.481771
0.439452	1.481472
0.443506	1.481179
0.447598	1.480892
0.451727	1.48061
0.455894	1.480334
0.460099	1.480063
0.464344	1.479797
0.468627	1.479537
0.47295	1.479282
0.477313	1.479031
0.481716	1.478786
0.48616	1.478545
0.490645	1.478308
0.495171	1.478077
0.499739	1.47785
0.504349	1.477627
0.509002	1.477408
0.513697	1.477193
0.518436	1.476983
0.523219	1.476776
0.528045	1.476574
0.532916	1.476375
0.537832	1.47618
0.542794	1.475989
0.547801	1.475801
0.552855	1.475616
0.557955	1.475436
0.563102	1.475258
0.568296	1.475084
0.573539	1.474913
0.57883	1.474745
0.584169	1.47458
0.589558	1.474418
0.594997	1.474259
0.600486	1.474103
0.606025	1.47395
0.611616	1.4738
0.617258	1.473652
0.622952	1.473507
0.628699	1.473365
0.634498	1.473225
0.640351	1.473088
0.646259	1.472953
0.65222	1.47282
0.658237	1.47269
0.664309	1.472562
0.670437	1.472437
0.676622	1.472313
0.682864	1.472192
0.689163	1.472073
0.695521	1.471956
0.701937	1.47184
0.708412	1.471727
0.714947	1.471616
0.721543	1.471507
0.728199	1.471399
0.734916	1.471293
0.741696	1.471189
0.748538	1.471087
0.755443	1.470987
0.762412	1.470888
0.769445	1.470791
0.776543	1.470695
0.783707	1.470601
0.790937	1.470508
0.798233	1.470417
0.805596	1.470327
0.813028	1.470239
0.820528	1.470152
0.828097	1.470066
0.835737	1.469982
0.843446	1.469899
0.851227	1.469817
0.859079	1.469737
0.867004	1.469658
0.875002	1.46958
0.883074	1.469503
0.891221	1.469427
0.899442	1.469352
0.907739	1.469278
0.916113	1.469205
0.924564	1.469134
0.933093	1.469063
0.941701	1.468993
0.950388	1.468924
0.959155	1.468857
0.968003	1.46879
0.976933	1.468723
0.985945	1.468658
0.995041	1.468593
1.00422	1.46853
1.01348	1.468467
1.02283	1.468405
1.03227	1.468343
1.04179	1.468282
1.0514	1.468222
1.0611	1.468163
1.07089	1.468104
1.08077	1.468046
1.09074	1.467988
1.1008	1.467931
1.11095	1.467874
1.1212	1.467819
1.13155	1.467763
1.14198	1.467708
1.15252	1.467654
1.16315	1.4676
1.17388	1.467546
1.18471	1.467493
1.19564	1.46744
1.20667	1.467388
1.2178	1.467336
1.22903	1.467285
1.24037	1.467233
1.25181	1.467182
1.26336	1.467132
1.27502	1.467081
1.28678	1.467031
1.29865	1.466981
1.31063	1.466932
1.32272	1.466882
1.33492	1.466833
1.34724	1.466784
1.35966	1.466735
1.37221	1.466686
1.38487	1.466638
1.39764	1.466589
1.41053	1.466541
1.42355	1.466492
1.43668	1.466444
1.44993	1.466396
1.46331	1.466347
1.47681	1.466299
1.49043	1.466251
1.50418	1.466203
1.51805	1.466154
1.53206	1.466106
1.54619	1.466058
1.56045	1.466009
1.57485	1.465961
1.58938	1.465912
1.60404	1.465863
1.61884	1.465814
1.63377	1.465765
1.64884	1.465715
1.66405	1.465666
1.6794	1.465616
1.6949	1.465566
1.71053	1.465515
1.72631	1.465465
1.74224	1.465414
1.75831	1.465363
1.77453	1.465311
1.7909	1.465259
1.80742	1.465207
1.82409	1.465154
1.84092	1.465101
1.8579	1.465048
1.87504	1.464994
1.89234	1.46494
1.90979	1.464885
1.92741	1.46483
1.94519	1.464774
1.96314	1.464718
1.98125	1.464661
1.99952	1.464603
2.01797	1.464545
2.03658	1.464487
2.05537	1.464427
2.07433	1.464367
2.09347	1.464307
2.11278	1.464246
2.13227	1.464184
2.15194	1.464121
2.17179	1.464057
2.19183	1.463993
2.21205	1.463928
2.23245	1.463862
2.25305	1.463796
2.27383	1.463728
2.29481	1.46366
2.31597	1.46359
2.33734	1.46352
2.3589	1.463449
2.38066	1.463376
2.40262	1.463303
2.42479	1.463229
2.44716	1.463154
2.46973	1.463077
2.49251	1.463
2.51551	1.462921
2.53871	1.462841
2.56213	1.46276
2.58577	1.462678
2.60962	1.462594
2.63369	1.46251
2.65799	1.462424
2.68251	1.462336
2.70726	1.462247
2.73223	1.462157
2.75743	1.462065
2.78287	1.461972
2.80854	1.461878
2.83445	1.461782
2.8606	1.461684
2.88699	1.461585
2.91362	1.461484
2.9405	1.461381
2.96762	1.461277
2.995	1.461171
3.02263	1.461063
3.05051	1.460954
3.07865	1.460842
3.10705	1.460729
3.13572	1.460614
3.16464	1.460497
3.19384	1.460377
3.2233	1.460256
3.25303	1.460133
3.28304	1.460007
3.31333	1.45988
3.34389	1.45975
3.37474	1.459618
3.40587	1.459483
3.43729	1.459346
3.469	1.459207
3.501	1.459065
3.5333	1.458921
3.56589	1.458774
3.59879	1.458625
3.63199	1.458473
3.66549	1.458318
3.6993	1.45816
3.73343	1.458
3.76787	1.457836
3.80263	1.45767
3.83771	1.457501
3.87311	1.457328
3.90884	1.457153
3.9449	1.456974
3.98129	1.456792
4.01802	1.456607
4.05508	1.456418
4.09249	1.456226
4.13024	1.456031
4.16835	1.455831
4.2068	1.455629
4.24561	1.455422
4.28477	1.455211
4.3243	1.454997
4.36419	1.454779
4.40445	1.454556
4.44508	1.45433
4.48608	1.454099
4.52747	1.453864
4.56923	1.453625
4.61138	1.453381
4.65392	1.453132
4.69686	1.452879
4.74018	1.452621
4.78391	1.452359
4.82804	1.452091
4.87258	1.451818
4.91753	1.451541
4.9629	1.451258
5.00868	1.450969
5.05488	1.450675
5.10151	1.450376
5.14857	1.450071
5.19607	1.44976
5.244	1.449443
5.29238	1.44912
5.3412	1.448792
5.39047	1.448456
5.4402	1.448115
5.49038	1.447767
5.54103	1.447412
5.59215	1.44705
5.64374	1.446682
5.6958	1.446306
5.74834	1.445923
5.80137	1.445533
5.85489	1.445135
5.9089	1.44473
5.96341	1.444317
6.01842	1.443896
6.07394	1.443466
6.12997	1.443029
6.18652	1.442583
6.24359	1.442128
6.30119	1.441664
6.35931	1.441192
6.41798	1.44071
6.47718	1.440219
6.53693	1.439718
6.59724	1.439207
6.6581	1.438686
6.71952	1.438156
6.7815	1.437614
6.84406	1.437062
6.9072	1.4365
6.97092	1.435926
7.03522	1.435341
7.10012	1.434744
7.16562	1.434135
7.23172	1.433515
7.29843	1.432882
7.36576	1.432236
7.43371	1.431578
7.50229	1.430906
7.57149	1.430221
7.64134	1.429523
7.71183	1.42881
7.78297	1.428083
7.85477	1.427342
7.92723	1.426585
8.00036	1.425813
8.07416	1.425026
8.14864	1.424223
8.22381	1.423403
8.29968	1.422567
8.37624	1.421714
8.45351	1.420844
8.5315	1.419955
8.6102	1.419049
8.68963	1.418124
8.76979	1.417179
8.85069	1.416216
8.93233	1.415233
9.01473	1.414229
9.0979	1.413204
9.18182	1.412159
9.26652	1.411091
9.35201	1.410001
9.43828	1.408889
9.52535	1.407753
9.61322	1.406593
9.7019	1.405409
9.7914	1.4042
9.88172	1.402965
9.97288	1.401704
10.0649	1.400417
10.1577	1.399102
10.2514	1.397758
10.346	1.396386

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: —

BaF₂ (Barium fluoride): all datasets

About BaF2 (Barium fluoride)

BaF₂, or barium fluoride, is a crystal that offers a wide transmission range, spanning from the ultraviolet into the mid-infrared regions. This material is commonly used in specialized optical applications such as scintillators in high-energy physics experiments, and as windows and lenses in infrared spectroscopy systems. It possesses a relatively low refractive index and high resistance to radiation damage, which makes it especially useful in extreme conditions. Additionally, BaF₂ has fast scintillation response times, making it advantageous in fast-timing applications. One drawback, however, is that the crystal is hygroscopic, making it sensitive to moisture and requiring proper storage and handling to maintain its optical properties. It also has a lower resistance to thermal and mechanical shock compared to other fluoride crystals, which can be a consideration depending on the intended application. Despite these limitations, BaF₂ remains a highly valuable material for specialized optical and photonic applications, owing to its broad transmission range and resilience to high-energy radiation.

More about BaF2 (Barium fluoride) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/BaF2/nk/Malitson.yml
ID: ds_d559449e59cb
API: /v1/datasets/ds_d559449e59cb

Plot