Optical constants

Refractive index of NaI (Sodium iodide)

Jellison et al. 2012: n 0.436–0.633 µm

Data: formula 1
Range: 0.436–0.633 µm
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.7862
Extinction coefficient k: 0

Permittivity ε₁: 3.19052
Permittivity ε₂: 0

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

Abbe number V_d: —
Chromatic dispersion dn/dλ: -0.205693 µm⁻¹

Group index n_g: 1.90707
Group velocity dispersion: 418.366 fs²/mm

Dispersion parameter D: -2282.41 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

# NaI (Sodium iodide): Jellison et al. 2012: n 0.436–0.633 µm
nai = ls.fetch_refractiveindex("main", "NaI", "Jellison", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(nai.range_nm)  # (436, 633) nm
eps = nai.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_d99b4262258c/lightsmith"
nai = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(nai.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (nai/jellison-2012).

# ... load nai as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=nai)],
    medium_index=1.0,
    wavelengths=ls.WavelengthRange(start_nm=436, stop_nm=633, 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_d99b4262258c/lightsmith?model=drude_lorentz"
nai_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{1.994 λ^{2}}{λ^{2} - {0.176}^{2}}

Valid from 0.436 to 0.633 µm.

Coefficients as stored

C_i	Value
C1	0.0
C2	1.994
C3	0.176

Comments and conditions

Room temperature

References

G. E. Jellison Jr., L. A. Boatner, J. O. Ramey, J. A. Kolopus, L. A. Ramey D. J. Singh. Refractive index of sodium iodide. J. Appl. Phys. 111, 043521 (2012)

doi:10.1063/1.3689746 Refractive index of sodium iodide, Journal of Applied Physics (2012)

Cite

G. E. Jellison et al.. Refractive index of sodium iodide. Journal of Applied Physics, 111, 043521 (2012), doi:10.1063/1.3689746; 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

NaI (Sodium iodide), Jellison et al. 2012: n 0.436–0.633 µm: n and k versus wavelength
λ (µm)	n
0.436	1.839069
0.436408	1.838833
0.436816	1.838599
0.437224	1.838364
0.437633	1.838131
0.438042	1.837898
0.438451	1.837665
0.438861	1.837433
0.439271	1.837202
0.439682	1.836971
0.440093	1.836741
0.440505	1.836512
0.440916	1.836283
0.441329	1.836054
0.441741	1.835826
0.442154	1.835599
0.442567	1.835372
0.442981	1.835146
0.443395	1.83492
0.44381	1.834695
0.444225	1.83447
0.44464	1.834246
0.445056	1.834023
0.445472	1.8338
0.445888	1.833577
0.446305	1.833355
0.446722	1.833134
0.44714	1.832913
0.447558	1.832693
0.447976	1.832473
0.448395	1.832254
0.448814	1.832035
0.449234	1.831817
0.449654	1.8316
0.450074	1.831383
0.450495	1.831166
0.450916	1.83095
0.451337	1.830735
0.451759	1.83052
0.452182	1.830305
0.452604	1.830091
0.453028	1.829878
0.453451	1.829665
0.453875	1.829452
0.454299	1.82924
0.454724	1.829029
0.455149	1.828818
0.455575	1.828608
0.456	1.828398
0.456427	1.828189
0.456853	1.82798
0.45728	1.827771
0.457708	1.827564
0.458136	1.827356
0.458564	1.827149
0.458993	1.826943
0.459422	1.826737
0.459851	1.826532
0.460281	1.826327
0.460712	1.826123
0.461142	1.825919
0.461573	1.825715
0.462005	1.825512
0.462437	1.82531
0.462869	1.825108
0.463302	1.824907
0.463735	1.824706
0.464168	1.824505
0.464602	1.824305
0.465037	1.824106
0.465471	1.823906
0.465907	1.823708
0.466342	1.82351
0.466778	1.823312
0.467214	1.823115
0.467651	1.822918
0.468088	1.822722
0.468526	1.822526
0.468964	1.822331
0.469402	1.822136
0.469841	1.821941
0.47028	1.821748
0.47072	1.821554
0.47116	1.821361
0.471601	1.821168
0.472041	1.820976
0.472483	1.820785
0.472924	1.820594
0.473367	1.820403
0.473809	1.820212
0.474252	1.820023
0.474695	1.819833
0.475139	1.819644
0.475583	1.819456
0.476028	1.819268
0.476473	1.81908
0.476918	1.818893
0.477364	1.818706
0.47781	1.81852
0.478257	1.818334
0.478704	1.818149
0.479152	1.817964
0.4796	1.817779
0.480048	1.817595
0.480497	1.817411
0.480946	1.817228
0.481396	1.817045
0.481846	1.816863
0.482296	1.816681
0.482747	1.816499
0.483198	1.816318
0.48365	1.816137
0.484102	1.815957
0.484555	1.815777
0.485008	1.815598
0.485461	1.815419
0.485915	1.81524
0.486369	1.815062
0.486824	1.814884
0.487279	1.814707
0.487734	1.81453
0.48819	1.814353
0.488647	1.814177
0.489104	1.814001
0.489561	1.813826
0.490018	1.813651
0.490477	1.813477
0.490935	1.813303
0.491394	1.813129
0.491853	1.812956
0.492313	1.812783
0.492773	1.81261
0.493234	1.812438
0.493695	1.812267
0.494157	1.812095
0.494619	1.811925
0.495081	1.811754
0.495544	1.811584
0.496007	1.811414
0.496471	1.811245
0.496935	1.811076
0.4974	1.810907
0.497865	1.810739
0.49833	1.810572
0.498796	1.810404
0.499262	1.810237
0.499729	1.810071
0.500196	1.809904
0.500664	1.809739
0.501132	1.809573
0.5016	1.809408
0.502069	1.809243
0.502538	1.809079
0.503008	1.808915
0.503478	1.808752
0.503949	1.808588
0.50442	1.808426
0.504892	1.808263
0.505364	1.808101
0.505836	1.80794
0.506309	1.807778
0.506782	1.807617
0.507256	1.807457
0.50773	1.807296
0.508205	1.807137
0.50868	1.806977
0.509156	1.806818
0.509632	1.806659
0.510108	1.806501
0.510585	1.806343
0.511062	1.806185
0.51154	1.806028
0.512018	1.805871
0.512497	1.805714
0.512976	1.805558
0.513456	1.805402
0.513936	1.805247
0.514416	1.805092
0.514897	1.804937
0.515378	1.804782
0.51586	1.804628
0.516342	1.804475
0.516825	1.804321
0.517308	1.804168
0.517792	1.804015
0.518276	1.803863
0.51876	1.803711
0.519245	1.803559
0.519731	1.803408
0.520216	1.803257
0.520703	1.803106
0.52119	1.802956
0.521677	1.802806
0.522165	1.802656
0.522653	1.802507
0.523141	1.802358
0.52363	1.80221
0.52412	1.802061
0.52461	1.801913
0.5251	1.801766
0.525591	1.801618
0.526082	1.801472
0.526574	1.801325
0.527067	1.801179
0.527559	1.801033
0.528052	1.800887
0.528546	1.800742
0.52904	1.800597
0.529535	1.800452
0.53003	1.800308
0.530525	1.800164
0.531021	1.80002
0.531518	1.799877
0.532015	1.799734
0.532512	1.799591
0.53301	1.799449
0.533508	1.799307
0.534007	1.799165
0.534506	1.799024
0.535006	1.798882
0.535506	1.798742
0.536006	1.798601
0.536507	1.798461
0.537009	1.798321
0.537511	1.798182
0.538014	1.798042
0.538516	1.797904
0.53902	1.797765
0.539524	1.797627
0.540028	1.797489
0.540533	1.797351
0.541038	1.797214
0.541544	1.797077
0.54205	1.79694
0.542557	1.796803
0.543064	1.796667
0.543572	1.796531
0.54408	1.796396
0.544589	1.796261
0.545098	1.796126
0.545607	1.795991
0.546118	1.795857
0.546628	1.795723
0.547139	1.795589
0.547651	1.795456
0.548163	1.795322
0.548675	1.79519
0.549188	1.795057
0.549701	1.794925
0.550215	1.794793
0.55073	1.794661
0.551244	1.79453
0.55176	1.794399
0.552276	1.794268
0.552792	1.794137
0.553309	1.794007
0.553826	1.793877
0.554344	1.793748
0.554862	1.793618
0.555381	1.793489
0.5559	1.79336
0.556419	1.793232
0.55694	1.793104
0.55746	1.792976
0.557981	1.792848
0.558503	1.792721
0.559025	1.792594
0.559548	1.792467
0.560071	1.79234
0.560594	1.792214
0.561118	1.792088
0.561643	1.791962
0.562168	1.791837
0.562694	1.791712
0.56322	1.791587
0.563746	1.791462
0.564273	1.791338
0.564801	1.791214
0.565329	1.79109
0.565857	1.790967
0.566386	1.790844
0.566916	1.790721
0.567446	1.790598
0.567976	1.790476
0.568507	1.790353
0.569038	1.790232
0.56957	1.79011
0.570103	1.789989
0.570636	1.789868
0.571169	1.789747
0.571703	1.789626
0.572238	1.789506
0.572773	1.789386
0.573308	1.789266
0.573844	1.789147
0.574381	1.789027
0.574918	1.788908
0.575455	1.78879
0.575993	1.788671
0.576531	1.788553
0.57707	1.788435
0.57761	1.788318
0.57815	1.7882
0.57869	1.788083
0.579231	1.787966
0.579773	1.787849
0.580315	1.787733
0.580857	1.787617
0.5814	1.787501
0.581944	1.787385
0.582488	1.78727
0.583032	1.787155
0.583577	1.78704
0.584123	1.786925
0.584669	1.786811
0.585216	1.786697
0.585763	1.786583
0.58631	1.786469
0.586858	1.786356
0.587407	1.786243
0.587956	1.78613
0.588506	1.786017
0.589056	1.785905
0.589607	1.785793
0.590158	1.785681
0.590709	1.785569
0.591262	1.785458
0.591814	1.785346
0.592368	1.785235
0.592921	1.785125
0.593476	1.785014
0.594031	1.784904
0.594586	1.784794
0.595142	1.784684
0.595698	1.784575
0.596255	1.784465
0.596812	1.784356
0.59737	1.784248
0.597929	1.784139
0.598488	1.784031
0.599047	1.783922
0.599607	1.783815
0.600168	1.783707
0.600729	1.7836
0.60129	1.783492
0.601853	1.783385
0.602415	1.783279
0.602978	1.783172
0.603542	1.783066
0.604106	1.78296
0.604671	1.782854
0.605236	1.782749
0.605802	1.782643
0.606368	1.782538
0.606935	1.782433
0.607503	1.782329
0.608071	1.782224
0.608639	1.78212
0.609208	1.782016
0.609778	1.781912
0.610348	1.781809
0.610918	1.781705
0.611489	1.781602
0.612061	1.781499
0.612633	1.781397
0.613206	1.781294
0.613779	1.781192
0.614353	1.78109
0.614927	1.780988
0.615502	1.780887
0.616077	1.780785
0.616653	1.780684
0.61723	1.780583
0.617807	1.780482
0.618384	1.780382
0.618962	1.780282
0.619541	1.780182
0.62012	1.780082
0.6207	1.779982
0.62128	1.779883
0.621861	1.779784
0.622442	1.779685
0.623024	1.779586
0.623607	1.779487
0.62419	1.779389
0.624773	1.779291
0.625357	1.779193
0.625942	1.779095
0.626527	1.778998
0.627113	1.7789
0.627699	1.778803
0.628286	1.778706
0.628873	1.77861
0.629461	1.778513
0.63005	1.778417
0.630638	1.778321
0.631228	1.778225
0.631818	1.778129
0.632409	1.778034
0.633	1.777938

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: —

NaI (Sodium iodide): all datasets

About NaI (Sodium iodide)

Sodium iodide (NaI) is a white, crystalline solid that can be prepared as transparent crystals suitable for optical applications. Notably, when doped with thallium (NaI:Tl), it becomes a scintillator material, capable of converting incident gamma rays into visible light. This property makes NaI:Tl crystals particularly valuable in radiation detection, gamma spectroscopy, and other nuclear medicine applications. However, NaI, being an alkali halide, is hygroscopic, meaning it readily absorbs moisture from the environment. Therefore, it requires careful handling and storage to prevent degradation, especially if it is to be used in optical systems.

Sodium iodide - Wikipedia

More about NaI (Sodium iodide) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/NaI/nk/Jellison.yml
ID: ds_d99b4262258c
API: /v1/datasets/ds_d99b4262258c

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