Optical constants

Refractive index of RbBr (Rubidium bromide)

Li 1976: n 0.21–50 µm

Data: formula 1
Range: 0.21–50 µm
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.55325
Extinction coefficient k: 0

Permittivity ε₁: 2.41258
Permittivity ε₂: 0

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

Abbe number V_d: 34.776
Chromatic dispersion dn/dλ: -0.0804328 µm⁻¹

Group index n_g: 1.60051
Group velocity dispersion: 162.403 fs²/mm

Dispersion parameter D: -885.995 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

# RbBr (Rubidium bromide): Li 1976: n 0.21–50 µm
rbbr = ls.fetch_refractiveindex("main", "RbBr", "Li", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(rbbr.range_nm)  # (210, 50000) nm
eps = rbbr.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_4e342c43ec61/lightsmith"
rbbr = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(rbbr.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (rbbr/li-1976).

# ... load rbbr as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=rbbr)],
    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_4e342c43ec61/lightsmith?model=drude_lorentz"
rbbr_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 = 0.45931 + \frac{0.16301 λ^{2}}{λ^{2} - {0.123}^{2}} + \frac{0.29841 λ^{2}}{λ^{2} - {0.146}^{2}} + \frac{0.17198 λ^{2}}{λ^{2} - {0.155}^{2}} + \frac{0.12186 λ^{2}}{λ^{2} - {0.178}^{2}} + \frac{0.13039 λ^{2}}{λ^{2} - {0.191}^{2}} + \frac{2.52 λ^{2}}{λ^{2} - {114.29}^{2}}

Valid from 0.21 to 50.0 µm.

Coefficients as stored

C_i	Value
C1	0.45931
C2	0.16301
C3	0.123
C4	0.29841
C5	0.146
C6	0.17198
C7	0.155
C8	0.12186
C9	0.178
C10	0.13039
C11	0.191
C12	2.52
C13	114.29

Comments and conditions

297 K (24 °C).

References

H. H. Li. Refractive index of alkali halides and its wavelength and temperature derivatives. J. Phys. Chem. Ref. Data 5, 329-528 (1976) and references therein.
* Sellmeier formula is derived by critical analysis of experimental data from several sources.

doi:10.1063/1.555536 Refractive index of alkali halides and its wavelength and temperature derivatives, Journal of Physical and Chemical Reference Data (1976)

Cite

H. H. Li. Refractive index of alkali halides and its wavelength and temperature derivatives. Journal of Physical and Chemical Reference Data, 5, 329-528 (1976), doi:10.1063/1.555536; 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

RbBr (Rubidium bromide), Li 1976: n 0.21–50 µm: n and k versus wavelength
λ (µm)	n
0.21	1.962238
0.2129	1.925171
0.21584	1.894186
0.218821	1.867728
0.221843	1.844761
0.224907	1.824562
0.228013	1.806606
0.231162	1.790504
0.234355	1.775958
0.237591	1.762733
0.240872	1.750644
0.244199	1.739542
0.247571	1.729304
0.250991	1.719828
0.254457	1.711028
0.257971	1.702833
0.261534	1.69518
0.265146	1.688018
0.268807	1.681299
0.27252	1.674984
0.276283	1.669038
0.280099	1.663429
0.283967	1.658131
0.287889	1.65312
0.291865	1.648372
0.295896	1.643869
0.299982	1.639594
0.304125	1.63553
0.308325	1.631662
0.312583	1.627979
0.3169	1.624468
0.321277	1.621118
0.325714	1.617919
0.330212	1.614863
0.334772	1.61194
0.339396	1.609143
0.344083	1.606464
0.348835	1.603898
0.353652	1.601439
0.358536	1.599079
0.363488	1.596815
0.368508	1.594641
0.373597	1.592552
0.378757	1.590545
0.383988	1.588615
0.389291	1.586759
0.394667	1.584973
0.400117	1.583253
0.405643	1.581598
0.411245	1.580003
0.416925	1.578465
0.422683	1.576984
0.42852	1.575555
0.434438	1.574177
0.440438	1.572848
0.446521	1.571565
0.452687	1.570326
0.458939	1.56913
0.465277	1.567975
0.471703	1.566859
0.478217	1.565781
0.484822	1.564739
0.491517	1.563732
0.498306	1.562758
0.505187	1.561816
0.512164	1.560905
0.519237	1.560024
0.526408	1.559171
0.533678	1.558346
0.541049	1.557547
0.548521	1.556774
0.556096	1.556025
0.563776	1.5553
0.571562	1.554598
0.579456	1.553918
0.587458	1.553259
0.595571	1.55262
0.603796	1.552001
0.612135	1.551402
0.620589	1.550821
0.62916	1.550257
0.637849	1.549711
0.646658	1.549181
0.655588	1.548668
0.664642	1.54817
0.673821	1.547687
0.683127	1.547218
0.692561	1.546763
0.702126	1.546322
0.711822	1.545894
0.721653	1.545479
0.731619	1.545076
0.741723	1.544685
0.751967	1.544305
0.762352	1.543937
0.77288	1.543579
0.783554	1.543232
0.794376	1.542895
0.805346	1.542567
0.816468	1.54225
0.827744	1.541941
0.839176	1.541641
0.850765	1.54135
0.862515	1.541067
0.874426	1.540792
0.886503	1.540525
0.898746	1.540266
0.911158	1.540014
0.923741	1.539769
0.936498	1.539531
0.949432	1.5393
0.962544	1.539075
0.975837	1.538857
0.989314	1.538645
1.00298	1.538438
1.01683	1.538238
1.03087	1.538043
1.04511	1.537853
1.05954	1.537669
1.07417	1.53749
1.08901	1.537315
1.10405	1.537146
1.1193	1.536981
1.13475	1.536821
1.15043	1.536665
1.16631	1.536513
1.18242	1.536366
1.19875	1.536222
1.21531	1.536082
1.23209	1.535947
1.24911	1.535814
1.26636	1.535686
1.28385	1.53556
1.30158	1.535438
1.31955	1.53532
1.33777	1.535204
1.35625	1.535091
1.37498	1.534982
1.39397	1.534875
1.41322	1.534771
1.43274	1.53467
1.45253	1.534571
1.47259	1.534475
1.49292	1.534381
1.51354	1.53429
1.53444	1.534201
1.55563	1.534114
1.57712	1.53403
1.5989	1.533947
1.62098	1.533867
1.64337	1.533788
1.66606	1.533712
1.68907	1.533637
1.7124	1.533564
1.73605	1.533493
1.76002	1.533423
1.78433	1.533356
1.80897	1.533289
1.83396	1.533224
1.85928	1.533161
1.88496	1.533099
1.91099	1.533038
1.93738	1.532979
1.96414	1.532921
1.99127	1.532864
2.01877	1.532809
2.04665	1.532754
2.07491	1.532701
2.10357	1.532648
2.13262	1.532597
2.16207	1.532547
2.19193	1.532497
2.2222	1.532449
2.25289	1.532401
2.284	1.532354
2.31555	1.532308
2.34753	1.532263
2.37995	1.532219
2.41282	1.532175
2.44614	1.532132
2.47992	1.532089
2.51417	1.532047
2.54889	1.532005
2.58409	1.531964
2.61978	1.531924
2.65596	1.531884
2.69264	1.531844
2.72983	1.531805
2.76753	1.531766
2.80575	1.531728
2.8445	1.53169
2.88378	1.531652
2.92361	1.531614
2.96398	1.531577
3.00492	1.53154
3.04642	1.531502
3.08849	1.531466
3.13114	1.531429
3.17438	1.531392
3.21822	1.531355
3.26267	1.531319
3.30773	1.531282
3.35341	1.531245
3.39972	1.531208
3.44667	1.531172
3.49427	1.531135
3.54253	1.531097
3.59145	1.53106
3.64105	1.531023
3.69134	1.530985
3.74232	1.530947
3.794	1.530909
3.8464	1.53087
3.89952	1.530831
3.95337	1.530792
4.00797	1.530752
4.06332	1.530712
4.11944	1.530672
4.17633	1.53063
4.23401	1.530589
4.29248	1.530547
4.35176	1.530504
4.41186	1.53046
4.47279	1.530416
4.53456	1.530372
4.59719	1.530326
4.66068	1.53028
4.72504	1.530233
4.7903	1.530185
4.85645	1.530136
4.92352	1.530087
4.99152	1.530036
5.06046	1.529985
5.13034	1.529932
5.2012	1.529879
5.27303	1.529824
5.34585	1.529768
5.41968	1.529711
5.49453	1.529653
5.57041	1.529593
5.64734	1.529532
5.72533	1.52947
5.8044	1.529407
5.88456	1.529341
5.96583	1.529275
6.04822	1.529207
6.13175	1.529137
6.21643	1.529065
6.30228	1.528992
6.38932	1.528917
6.47756	1.528841
6.56702	1.528762
6.65771	1.528681
6.74966	1.528599
6.84287	1.528514
6.93738	1.528427
7.03319	1.528338
7.13032	1.528247
7.22879	1.528153
7.32862	1.528057
7.42983	1.527958
7.53244	1.527857
7.63647	1.527753
7.74193	1.527646
7.84885	1.527537
7.95725	1.527425
8.06714	1.527309
8.17855	1.527191
8.2915	1.527069
8.40601	1.526944
8.5221	1.526816
8.6398	1.526684
8.75912	1.526549
8.88009	1.52641
9.00272	1.526267
9.12706	1.526121
9.2531	1.52597
9.38089	1.525815
9.51045	1.525656
9.64179	1.525493
9.77495	1.525325
9.90995	1.525152
10.0468	1.524975
10.1856	1.524793
10.3262	1.524605
10.4688	1.524413
10.6134	1.524215
10.76	1.524011
10.9086	1.523802
11.0592	1.523587
11.212	1.523366
11.3668	1.523139
11.5238	1.522905
11.683	1.522665
11.8443	1.522418
12.0079	1.522164
12.1737	1.521902
12.3418	1.521634
12.5123	1.521357
12.6851	1.521073
12.8603	1.520781
13.0379	1.52048
13.2179	1.520171
13.4005	1.519853
13.5855	1.519526
13.7732	1.51919
13.9634	1.518843
14.1562	1.518487
14.3517	1.518121
14.5499	1.517744
14.7509	1.517356
14.9546	1.516957
15.1611	1.516547
15.3705	1.516124
15.5828	1.51569
15.798	1.515242
16.0162	1.514782
16.2373	1.514308
16.4616	1.513821
16.6889	1.513319
16.9194	1.512802
17.1531	1.51227
17.39	1.511723
17.6301	1.51116
17.8736	1.510579
18.1205	1.509982
18.3707	1.509367
18.6244	1.508734
18.8816	1.508082
19.1424	1.50741
19.4068	1.506719
19.6748	1.506006
19.9465	1.505273
20.222	1.504517
20.5012	1.503739
20.7844	1.502937
21.0714	1.50211
21.3624	1.501259
21.6574	1.500382
21.9565	1.499478
22.2598	1.498546
22.5672	1.497586
22.8788	1.496597
23.1948	1.495576
23.5151	1.494525
23.8399	1.49344
24.1691	1.492322
24.5029	1.491169
24.8413	1.48998
25.1844	1.488754
25.5322	1.487488
25.8848	1.486183
26.2423	1.484836
26.6047	1.483447
26.9721	1.482012
27.3446	1.480532
27.7223	1.479004
28.1051	1.477427
28.4933	1.475798
28.8868	1.474115
29.2857	1.472378
29.6902	1.470583
30.1002	1.468729
30.5159	1.466812
30.9373	1.464832
31.3646	1.462785
31.7978	1.460668
32.2369	1.458479
32.6821	1.456216
33.1335	1.453874
33.5911	1.451451
34.055	1.448943
34.5253	1.446348
35.0021	1.44366
35.4855	1.440877
35.9756	1.437994
36.4724	1.435007
36.9761	1.431911
37.4868	1.428701
38.0045	1.425373
38.5293	1.42192
39.0614	1.418337
39.6009	1.414619
40.1478	1.410758
40.7023	1.406748
41.2644	1.402581
41.8343	1.398249
42.412	1.393745
42.9977	1.38906
43.5916	1.384184
44.1936	1.379107
44.8039	1.373818
45.4227	1.368306
46.05	1.362559
46.6859	1.356563
47.3307	1.350304
47.9844	1.343766
48.647	1.336934
49.3189	1.329788
50	1.322309

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: —

RbBr (Rubidium bromide): all datasets

Li 1976: n 0.21–50 µm n 0.21–50 µm default

About RbBr (Rubidium bromide)

Rubidium bromide (RbBr) is an ionic compound consisting of rubidium cations (Rb⁺) and bromide anions (Br^-). This white, crystalline solid is highly soluble in water, producing a solution that is neutral in pH. Like other alkali metal bromides, rubidium bromide is typically used in the laboratory setting rather than for commercial applications. Due to its optical properties, it may be of interest in certain optical and laser applications. In general, RbBr shares many of the properties common to other alkali metal bromides, such as high solubility in water, hygroscopic nature, and good conductivity when dissolved or melted. Handling should be done with care as it reacts with moisture and can be corrosive.

More about RbBr (Rubidium bromide) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/RbBr/nk/Li.yml
ID: ds_4e342c43ec61
API: /v1/datasets/ds_4e342c43ec61

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