Optical constants

Refractive index of NaBr (Sodium bromide)

Li 1976: n 0.21–34 µm

Data: formula 1
Range: 0.21–34 µm
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.64301
Extinction coefficient k: 0

Permittivity ε₁: 2.69949
Permittivity ε₂: 0

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

Abbe number V_d: 31.716
Chromatic dispersion dn/dλ: -0.102956 µm⁻¹

Group index n_g: 1.70351
Group velocity dispersion: 203.695 fs²/mm

Dispersion parameter D: -1111.27 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

# NaBr (Sodium bromide): Li 1976: n 0.21–34 µm
nabr = ls.fetch_refractiveindex("main", "NaBr", "Li", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(nabr.range_nm)  # (210, 34000) nm
eps = nabr.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_a6faea122677/lightsmith"
nabr = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(nabr.source)  # citation and provenance travel with the data

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

# ... load nabr as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=nabr)],
    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_a6faea122677/lightsmith?model=drude_lorentz"
nabr_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 = 0.06728 + \frac{1.10463 λ^{2}}{λ^{2} - {0.125}^{2}} + \frac{0.18816 λ^{2}}{λ^{2} - {0.145}^{2}} + \frac{0.00243 λ^{2}}{λ^{2} - {0.176}^{2}} + \frac{0.24454 λ^{2}}{λ^{2} - {0.188}^{2}} + \frac{3.796 λ^{2}}{λ^{2} - {74.63}^{2}}

Valid from 0.21 to 34.0 µm.

Coefficients as stored

C_i	Value
C1	0.06728
C2	1.10463
C3	0.125
C4	0.18816
C5	0.145
C6	0.00243
C7	0.176
C8	0.24454
C9	0.188
C10	3.796
C11	74.63

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

NaBr (Sodium bromide), Li 1976: n 0.21–34 µm: n and k versus wavelength
λ (µm)	n
0.21	2.09223
0.212695	2.057176
0.215424	2.027235
0.218188	2.001231
0.220987	1.978337
0.223823	1.957954
0.226695	1.939635
0.229603	1.923041
0.232549	1.907908
0.235533	1.894026
0.238555	1.88123
0.241616	1.869381
0.244716	1.858367
0.247856	1.848095
0.251037	1.838484
0.254258	1.829469
0.25752	1.820992
0.260824	1.813003
0.264171	1.805458
0.267561	1.798321
0.270994	1.791558
0.274471	1.785139
0.277993	1.779039
0.281559	1.773235
0.285172	1.767705
0.288831	1.76243
0.292537	1.757394
0.296291	1.752582
0.300092	1.747978
0.303943	1.743572
0.307843	1.73935
0.311793	1.735302
0.315793	1.731419
0.319845	1.72769
0.323949	1.724109
0.328106	1.720666
0.332316	1.717356
0.33658	1.71417
0.340898	1.711103
0.345272	1.70815
0.349703	1.705304
0.35419	1.702561
0.358734	1.699915
0.363337	1.697363
0.367999	1.6949
0.372721	1.692522
0.377503	1.690226
0.382347	1.688007
0.387253	1.685864
0.392222	1.683791
0.397255	1.681788
0.402352	1.67985
0.407514	1.677976
0.412743	1.676162
0.418039	1.674406
0.423403	1.672707
0.428836	1.671061
0.434338	1.669467
0.439911	1.667923
0.445555	1.666427
0.451272	1.664978
0.457063	1.663573
0.462927	1.66221
0.468867	1.66089
0.474883	1.659609
0.480976	1.658367
0.487148	1.657161
0.493398	1.655992
0.499729	1.654858
0.506141	1.653757
0.512636	1.652688
0.519213	1.651651
0.525875	1.650643
0.532623	1.649665
0.539457	1.648716
0.546379	1.647793
0.553389	1.646898
0.56049	1.646027
0.567681	1.645182
0.574965	1.64436
0.582343	1.643562
0.589815	1.642786
0.597383	1.642032
0.605048	1.641299
0.612811	1.640586
0.620674	1.639894
0.628638	1.63922
0.636704	1.638565
0.644874	1.637928
0.653148	1.637309
0.661528	1.636707
0.670017	1.636121
0.678614	1.635551
0.687321	1.634996
0.69614	1.634457
0.705072	1.633932
0.714119	1.633422
0.723282	1.632925
0.732562	1.632441
0.741962	1.63197
0.751482	1.631512
0.761124	1.631066
0.77089	1.630632
0.780781	1.63021
0.7908	1.629798
0.800946	1.629398
0.811223	1.629008
0.821632	1.628628
0.832174	1.628258
0.842852	1.627898
0.853667	1.627547
0.86462	1.627205
0.875714	1.626872
0.88695	1.626548
0.898331	1.626232
0.909857	1.625924
0.921532	1.625624
0.933356	1.625332
0.945332	1.625047
0.957461	1.62477
0.969747	1.624499
0.982189	1.624236
0.994792	1.623979
1.00756	1.623728
1.02048	1.623484
1.03358	1.623245
1.04684	1.623013
1.06027	1.622787
1.07388	1.622566
1.08766	1.62235
1.10161	1.62214
1.11575	1.621935
1.13006	1.621735
1.14456	1.621539
1.15925	1.621349
1.17412	1.621163
1.18919	1.620981
1.20445	1.620804
1.2199	1.620631
1.23555	1.620462
1.25141	1.620297
1.26746	1.620135
1.28373	1.619978
1.3002	1.619824
1.31688	1.619673
1.33378	1.619526
1.35089	1.619383
1.36822	1.619242
1.38578	1.619105
1.40356	1.61897
1.42157	1.618839
1.43981	1.61871
1.45828	1.618584
1.47699	1.618461
1.49595	1.61834
1.51514	1.618222
1.53458	1.618106
1.55427	1.617992
1.57421	1.617881
1.59441	1.617772
1.61487	1.617665
1.63559	1.61756
1.65658	1.617456
1.67783	1.617355
1.69936	1.617256
1.72117	1.617158
1.74325	1.617062
1.76562	1.616968
1.78827	1.616875
1.81122	1.616784
1.83446	1.616694
1.858	1.616605
1.88184	1.616518
1.90598	1.616432
1.93044	1.616347
1.95521	1.616264
1.98029	1.616181
2.0057	1.6161
2.03144	1.616019
2.0575	1.61594
2.0839	1.615861
2.11064	1.615783
2.13772	1.615706
2.16515	1.615629
2.19293	1.615553
2.22107	1.615478
2.24957	1.615404
2.27844	1.61533
2.30767	1.615256
2.33728	1.615183
2.36727	1.61511
2.39764	1.615037
2.42841	1.614965
2.45957	1.614893
2.49113	1.614821
2.52309	1.614749
2.55546	1.614677
2.58825	1.614606
2.62146	1.614534
2.6551	1.614462
2.68917	1.614391
2.72367	1.614319
2.75862	1.614246
2.79401	1.614174
2.82986	1.614101
2.86617	1.614028
2.90295	1.613955
2.9402	1.613881
2.97792	1.613806
3.01613	1.613731
3.05483	1.613656
3.09403	1.613579
3.13373	1.613502
3.17394	1.613425
3.21466	1.613346
3.25591	1.613267
3.29769	1.613187
3.34	1.613106
3.38286	1.613024
3.42626	1.61294
3.47022	1.612856
3.51475	1.612771
3.55985	1.612684
3.60552	1.612596
3.65179	1.612507
3.69864	1.612416
3.7461	1.612324
3.79417	1.61223
3.84285	1.612135
3.89216	1.612038
3.9421	1.611939
3.99268	1.611839
4.04391	1.611737
4.0958	1.611632
4.14835	1.611526
4.20158	1.611418
4.25549	1.611308
4.31009	1.611195
4.36539	1.61108
4.4214	1.610963
4.47814	1.610844
4.53559	1.610722
4.59379	1.610597
4.65273	1.61047
4.71243	1.61034
4.7729	1.610207
4.83414	1.610071
4.89617	1.609932
4.95899	1.60979
5.02262	1.609645
5.08706	1.609496
5.15234	1.609344
5.21845	1.609189
5.2854	1.60903
5.35322	1.608867
5.42191	1.6087
5.49148	1.60853
5.56194	1.608355
5.6333	1.608176
5.70558	1.607993
5.77879	1.607806
5.85294	1.607614
5.92804	1.607417
6.0041	1.607215
6.08114	1.607009
6.15917	1.606797
6.2382	1.60658
6.31824	1.606358
6.39931	1.60613
6.48142	1.605897
6.56458	1.605657
6.64881	1.605412
6.73412	1.60516
6.82053	1.604902
6.90804	1.604638
6.99668	1.604366
7.08645	1.604088
7.17738	1.603803
7.26947	1.60351
7.36275	1.60321
7.45722	1.602902
7.5529	1.602586
7.64981	1.602262
7.74797	1.60193
7.84738	1.601589
7.94807	1.601239
8.05006	1.60088
8.15335	1.600511
8.25796	1.600133
8.36392	1.599745
8.47124	1.599347
8.57993	1.598938
8.69002	1.598518
8.80152	1.598088
8.91446	1.597646
9.02884	1.597192
9.14469	1.596726
9.26202	1.596248
9.38086	1.595757
9.50123	1.595253
9.62314	1.594735
9.74661	1.594204
9.87167	1.593658
9.99834	1.593098
10.1266	1.592523
10.2566	1.591932
10.3882	1.591325
10.5215	1.590702
10.6565	1.590062
10.7932	1.589404
10.9317	1.588728
11.0719	1.588035
11.214	1.587322
11.3579	1.586589
11.5036	1.585837
11.6512	1.585064
11.8007	1.58427
11.9521	1.583453
12.1055	1.582614
12.2608	1.581752
12.4181	1.580866
12.5775	1.579956
12.7389	1.57902
12.9023	1.578058
13.0679	1.577069
13.2355	1.576052
13.4054	1.575007
13.5774	1.573932
13.7516	1.572826
13.928	1.57169
14.1067	1.570521
14.2877	1.569319
14.4711	1.568082
14.6567	1.56681
14.8448	1.565502
15.0353	1.564156
15.2282	1.562771
15.4236	1.561345
15.6215	1.559879
15.8219	1.558369
16.0249	1.556816
16.2306	1.555216
16.4388	1.55357
16.6497	1.551875
16.8634	1.55013
17.0797	1.548332
17.2989	1.546481
17.5209	1.544574
17.7457	1.54261
17.9734	1.540586
18.204	1.538501
18.4376	1.536352
18.6741	1.534137
18.9137	1.531854
19.1564	1.529501
19.4022	1.527074
19.6512	1.524571
19.9033	1.521989
20.1587	1.519326
20.4173	1.516578
20.6793	1.513742
20.9447	1.510816
21.2134	1.507794
21.4856	1.504675
21.7613	1.501453
22.0405	1.498125
22.3233	1.494687
22.6097	1.491134
22.8998	1.487461
23.1937	1.483664
23.4913	1.479738
23.7927	1.475676
24.098	1.471474
24.4072	1.467125
24.7203	1.462623
25.0375	1.457961
25.3588	1.453132
25.6841	1.448128
26.0137	1.442942
26.3475	1.437564
26.6855	1.431986
27.0279	1.426198
27.3747	1.42019
27.726	1.413951
28.0817	1.407469
28.4421	1.400732
28.807	1.393726
29.1766	1.386438
29.551	1.378852
29.9302	1.370952
30.3142	1.362719
30.7032	1.354136
31.0971	1.345181
31.4961	1.335833
31.9002	1.326067
32.3096	1.315858
32.7241	1.305176
33.144	1.293991
33.5693	1.28227
34	1.269974

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: —

NaBr (Sodium bromide): all datasets

Li 1976: n 0.21–34 µm n 0.21–34 µm default

About NaBr (Sodium bromide)

Sodium bromide (NaBr) is a white crystalline solid commonly used in various applications. In its pure form, it can be processed into clear crystalline windows or pieces, showcasing transparency not just in the visible range but also extensively into the infrared spectrum. This characteristic transparency in the infrared region is particularly beneficial, making NaBr an invaluable material in infrared spectroscopy and other related optical applications.

Sodium bromide - Wikipedia

More about NaBr (Sodium bromide) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/NaBr/nk/Li.yml
ID: ds_a6faea122677
API: /v1/datasets/ds_a6faea122677

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