Optical constants

Refractive index of CsI (Cesium iodide)

Rodney 1955: n 0.2967–50 µm

Data: formula 1
Range: 0.2967–50 µm
Licence: CC0-1.0

Axis Log x Log y

Click the plot to set the calculator wavelength.

At one wavelength

Refractive index n: 1.78718
Extinction coefficient k: 0

Permittivity ε₁: 3.19402
Permittivity ε₂: 0

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

Abbe number V_d: 23.989
Chromatic dispersion dn/dλ: -0.165095 µm⁻¹

Group index n_g: 1.88419
Group velocity dispersion: 340.181 fs²/mm

Dispersion parameter D: -1855.87 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

# CsI (Cesium iodide): Rodney 1955: n 0.2967–50 µm
csi = ls.fetch_refractiveindex("main", "CsI", "Rodney", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(csi.range_nm)  # (296.7, 50000) nm
eps = csi.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_1d37a495fac8/lightsmith"
csi = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(csi.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (csi/rodney-1955).

# ... load csi as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=csi)],
    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_1d37a495fac8/lightsmith?model=drude_lorentz"
csi_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{0.34617251 λ^{2}}{λ^{2} - {0.0229567}^{2}} + \frac{1.0080886 λ^{2}}{λ^{2} - {0.1466}^{2}} + \frac{0.285518 λ^{2}}{λ^{2} - {0.181}^{2}} + \frac{0.39743178 λ^{2}}{λ^{2} - {0.212}^{2}} + \frac{3.3605359 λ^{2}}{λ^{2} - {161.0}^{2}}

Valid from 0.2967 to 50.0 µm.

Coefficients as stored

C_i	Value
C1	0.0
C2	0.34617251
C3	0.0229567
C4	1.0080886
C5	0.1466
C6	0.285518
C7	0.181
C8	0.39743178
C9	0.212
C10	3.3605359
C11	161.0

Comments and conditions

24 °C

References

W. S. Rodney. Optical properties of cesium iodide. J. Opt. Soc. Am. 45, 987-991 (1955)

doi:10.1364/josa.45.000987 Optical Properties of Cesium Iodide*, Journal of the Optical Society of America (1955)

Cite

William S. Rodney. Optical Properties of Cesium Iodide*. Journal of the Optical Society of America, 45, 987 (1955), doi:10.1364/josa.45.000987; 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

CsI (Cesium iodide), Rodney 1955: n 0.2967–50 µm: n and k versus wavelength
λ (µm)	n
0.2967	1.987131
0.300537	1.977402
0.304424	1.968223
0.308361	1.959547
0.312349	1.951334
0.316388	1.943548
0.32048	1.936157
0.324625	1.929132
0.328823	1.922448
0.333076	1.916081
0.337383	1.91001
0.341746	1.904216
0.346166	1.898681
0.350643	1.893389
0.355178	1.888325
0.359771	1.883477
0.364424	1.878831
0.369137	1.874377
0.373911	1.870103
0.378746	1.866
0.383645	1.862059
0.388606	1.858271
0.393632	1.854629
0.398723	1.851126
0.403879	1.847754
0.409102	1.844507
0.414393	1.841379
0.419752	1.838364
0.425181	1.835458
0.43068	1.832656
0.43625	1.829952
0.441891	1.827342
0.447606	1.824823
0.453395	1.822391
0.459259	1.82004
0.465198	1.81777
0.471214	1.815575
0.477308	1.813453
0.483481	1.811401
0.489734	1.809416
0.496068	1.807496
0.502483	1.805638
0.508982	1.803839
0.515564	1.802097
0.522232	1.800411
0.528985	1.798778
0.535827	1.797195
0.542756	1.795663
0.549776	1.794177
0.556886	1.792737
0.564088	1.791341
0.571383	1.789988
0.578772	1.788676
0.586258	1.787403
0.593839	1.786169
0.601519	1.784971
0.609299	1.783809
0.617178	1.782682
0.62516	1.781588
0.633245	1.780525
0.641435	1.779494
0.64973	1.778494
0.658133	1.777522
0.666644	1.776578
0.675266	1.775661
0.683999	1.774771
0.692845	1.773907
0.701805	1.773067
0.710881	1.772251
0.720075	1.771458
0.729388	1.770687
0.73882	1.769938
0.748375	1.769211
0.758054	1.768503
0.767858	1.767816
0.777788	1.767147
0.787847	1.766498
0.798036	1.765866
0.808357	1.765252
0.818811	1.764655
0.8294	1.764074
0.840127	1.763509
0.850992	1.76296
0.861997	1.762425
0.873145	1.761906
0.884437	1.7614
0.895875	1.760908
0.907462	1.76043
0.919197	1.759964
0.931085	1.759511
0.943127	1.759071
0.955324	1.758642
0.967679	1.758224
0.980193	1.757818
0.99287	1.757423
1.00571	1.757038
1.01872	1.756664
1.03189	1.7563
1.04524	1.755945
1.05875	1.7556
1.07245	1.755263
1.08632	1.754936
1.10037	1.754617
1.1146	1.754307
1.12901	1.754005
1.14361	1.753711
1.1584	1.753425
1.17338	1.753146
1.18856	1.752874
1.20393	1.75261
1.2195	1.752352
1.23527	1.752102
1.25125	1.751857
1.26743	1.751619
1.28382	1.751387
1.30042	1.751162
1.31724	1.750942
1.33428	1.750727
1.35153	1.750519
1.36901	1.750315
1.38672	1.750117
1.40465	1.749924
1.42282	1.749736
1.44122	1.749553
1.45986	1.749374
1.47874	1.7492
1.49786	1.74903
1.51723	1.748865
1.53685	1.748704
1.55673	1.748546
1.57686	1.748393
1.59725	1.748244
1.61791	1.748098
1.63883	1.747957
1.66003	1.747818
1.6815	1.747683
1.70324	1.747552
1.72527	1.747423
1.74758	1.747298
1.77018	1.747176
1.79308	1.747057
1.81627	1.746941
1.83976	1.746828
1.86355	1.746717
1.88765	1.746609
1.91206	1.746504
1.93679	1.746401
1.96184	1.746301
1.98721	1.746203
2.01291	1.746108
2.03894	1.746014
2.06531	1.745923
2.09202	1.745834
2.11908	1.745747
2.14648	1.745662
2.17424	1.745579
2.20236	1.745498
2.23084	1.745419
2.25969	1.745342
2.28892	1.745266
2.31852	1.745192
2.3485	1.74512
2.37888	1.745049
2.40964	1.74498
2.44081	1.744912
2.47237	1.744846
2.50435	1.744781
2.53673	1.744718
2.56954	1.744655
2.60277	1.744594
2.63643	1.744535
2.67053	1.744476
2.70507	1.744419
2.74005	1.744362
2.77549	1.744307
2.81138	1.744253
2.84774	1.7442
2.88457	1.744148
2.92187	1.744096
2.95966	1.744046
2.99794	1.743997
3.03671	1.743948
3.07598	1.7439
3.11576	1.743853
3.15606	1.743806
3.19687	1.743761
3.23822	1.743716
3.2801	1.743671
3.32252	1.743627
3.36548	1.743584
3.40901	1.743542
3.4531	1.743499
3.49776	1.743458
3.54299	1.743417
3.58881	1.743376
3.63522	1.743335
3.68224	1.743296
3.72986	1.743256
3.7781	1.743217
3.82696	1.743178
3.87645	1.743139
3.92658	1.743101
3.97736	1.743062
4.0288	1.743024
4.0809	1.742987
4.13368	1.742949
4.18714	1.742911
4.24129	1.742874
4.29614	1.742837
4.3517	1.742799
4.40798	1.742762
4.46499	1.742725
4.52273	1.742687
4.58123	1.74265
4.64047	1.742613
4.70049	1.742575
4.76128	1.742537
4.82285	1.7425
4.88522	1.742462
4.9484	1.742423
5.0124	1.742385
5.07722	1.742346
5.14289	1.742308
5.2094	1.742268
5.27677	1.742229
5.34501	1.742189
5.41414	1.742149
5.48416	1.742108
5.55508	1.742067
5.62692	1.742025
5.69969	1.741983
5.77341	1.741941
5.84807	1.741898
5.9237	1.741854
6.00031	1.74181
6.07791	1.741765
6.15652	1.741719
6.23614	1.741673
6.31679	1.741626
6.39848	1.741578
6.48123	1.74153
6.56505	1.74148
6.64995	1.74143
6.73595	1.741379
6.82307	1.741327
6.91131	1.741274
7.00069	1.74122
7.09123	1.741165
7.18294	1.741109
7.27583	1.741052
7.36993	1.740993
7.46524	1.740934
7.56179	1.740873
7.65958	1.740811
7.75864	1.740748
7.85898	1.740684
7.96062	1.740618
8.06357	1.74055
8.16785	1.740481
8.27348	1.740411
8.38048	1.740339
8.48886	1.740265
8.59865	1.74019
8.70985	1.740113
8.82249	1.740034
8.93659	1.739954
9.05217	1.739872
9.16923	1.739787
9.28782	1.739701
9.40793	1.739612
9.5296	1.739522
9.65285	1.739429
9.77768	1.739334
9.90414	1.739237
10.0322	1.739138
10.162	1.739036
10.2934	1.738931
10.4265	1.738824
10.5614	1.738714
10.6979	1.738602
10.8363	1.738487
10.9764	1.738369
11.1184	1.738248
11.2622	1.738123
11.4078	1.737996
11.5554	1.737866
11.7048	1.737732
11.8562	1.737595
12.0095	1.737454
12.1648	1.73731
12.3222	1.737162
12.4815	1.737011
12.6429	1.736855
12.8064	1.736696
12.9721	1.736532
13.1398	1.736364
13.3098	1.736192
13.4819	1.736016
13.6562	1.735834
13.8329	1.735648
14.0117	1.735458
14.193	1.735262
14.3765	1.735061
14.5624	1.734855
14.7508	1.734644
14.9415	1.734427
15.1348	1.734204
15.3305	1.733976
15.5288	1.733741
15.7296	1.7335
15.933	1.733253
16.1391	1.733
16.3478	1.732739
16.5592	1.732472
16.7734	1.732198
16.9903	1.731916
17.21	1.731627
17.4326	1.731331
17.6581	1.731026
17.8864	1.730714
18.1177	1.730392
18.352	1.730063
18.5894	1.729724
18.8298	1.729377
19.0733	1.72902
19.32	1.728654
19.5698	1.728277
19.8229	1.727891
20.0793	1.727494
20.339	1.727087
20.602	1.726668
20.8685	1.726238
21.1383	1.725797
21.4117	1.725344
21.6886	1.724878
21.9691	1.724399
22.2532	1.723908
22.541	1.723403
22.8326	1.722884
23.1278	1.722351
23.4269	1.721804
23.7299	1.721242
24.0368	1.720664
24.3477	1.72007
24.6625	1.71946
24.9815	1.718832
25.3046	1.718188
25.6318	1.717526
25.9633	1.716845
26.2991	1.716146
26.6392	1.715426
26.9837	1.714687
27.3327	1.713927
27.6862	1.713146
28.0442	1.712343
28.4069	1.711518
28.7743	1.710669
29.1464	1.709796
29.5234	1.708898
29.9052	1.707975
30.292	1.707025
30.6837	1.706049
31.0805	1.705044
31.4825	1.704011
31.8896	1.702948
32.3021	1.701855
32.7198	1.700729
33.143	1.699572
33.5716	1.69838
34.0058	1.697154
34.4455	1.695892
34.891	1.694593
35.3423	1.693256
35.7993	1.691879
36.2623	1.690462
36.7313	1.689002
37.2063	1.687499
37.6875	1.685951
38.1749	1.684356
38.6686	1.682713
39.1687	1.681021
39.6752	1.679277
40.1883	1.677479
40.7081	1.675627
41.2346	1.673718
41.7678	1.671749
42.308	1.66972
42.8551	1.667627
43.4094	1.665468
43.9708	1.663242
44.5394	1.660944
45.1155	1.658574
45.6989	1.656128
46.2899	1.653603
46.8886	1.650996
47.495	1.648304
48.1092	1.645524
48.7314	1.642652
49.3616	1.639685
50	1.636619

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: —

CsI (Cesium iodide): all datasets

About CsI (Cesium iodide)

Caesium iodide (CsI) is an inorganic compound known for its wide range of applications, from scintillation counters in high-energy physics to the field of medical imaging. This compound forms colorless, water-soluble crystals and has high gamma-ray stopping power, making it particularly useful as a scintillator material. It is also notable for its transparency in the wide spectral range from ultraviolet to long-wavelength infrared, which makes it valuable in infrared optics. In addition, CsI is often used in mass spectrometry as a matrix to help ionize samples. Like other caesium compounds, CsI should be handled with care due to its reactivity and potential health risks associated with iodine and caesium, such as thyroid gland issues and cellular ion channel disruptions. As a result, strict safety protocols are essential for its handling and storage. Overall, CsI is a highly versatile material with a plethora of applications in both scientific research and industrial processes.

Caesium iodide - Wikipedia

More about CsI (Cesium iodide) →

Provenance

Version: 1 (snapshot c5c2f18)
Source page: refractiveindex.info
Original file: database/data/main/CsI/nk/Rodney.yml
ID: ds_1d37a495fac8
API: /v1/datasets/ds_1d37a495fac8

Plot