Optical constants
Refractive index of CsI - Caesium iodide (CRYSTRAN)
CsI - Caesium iodide: n,k 0.5–50 µm
- Data
- tabulated n + tabulated k
- Range
- 0.5–50 µm
- Points
- 51
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength. Note: k data cover 238-40000 nm only; k = 0 elsewhere in the n range 500-50000 nm.
At one wavelength
- Refractive index n
- 1.79778
- Extinction coefficient k
- 6.19768e-07
- Permittivity ε1
- 3.23201
- Permittivity ε2
- 2.22841e-06
- Absorption coefficient α
- 0.132543 cm⁻¹
- Penetration depth δ = λ/(2πk)
- 1.50894e+08 nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- -0.0984 µm⁻¹
- Group index ng
- 1.8556
- Group velocity dispersion
- — fs²/mm
- Dispersion parameter D
- — ps/(nm·km)
- Photon energy
- 2.11001 eV
ε = (n + ik)², α = 4πk/λ, ng = 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 - Caesium iodide (CRYSTRAN): CsI - Caesium iodide
crystran_csi = ls.fetch_refractiveindex("specs", "CRYSTRAN-optical", "CsI", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(crystran_csi.range_nm) # (500, 50000) nm
eps = crystran_csi.eps([633]) # complex permittivityDownloads 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_afaa47a059a4/lightsmith"
crystran_csi = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(crystran_csi.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (crystran-csi/crystran).
# ... load crystran_csi as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=crystran_csi)],
medium_index=1.0,
wavelengths=ls.WavelengthRange(start_nm=500, stop_nm=1000, num=81),
)
res = ls.solve(sim) # exact Mie for a sphere
print(res.q_ext) # extinction efficiency at each wavelengthSame spec runs with DDA, FDTD, BEM or T-matrix: ls.compare(sim, ["mie", "dda"]).
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.
Comments and conditions
Properties
- density
- value: 4510
- thermal dispersion
- type: constant, value: -9.93e-05
- thermal expansion
- value: 48.3e-06, temperature: 293
- hardness
- type: Knoop, value: 1.96e8, indenter mass: 0.2
- melting point
- value: 894
- thermal conductivity
- value: 1.1, temperature: 298
- youngs modulus
- value: 5.3e9
- poissons ratio
- value: 0.214
- solubility
- value: 440, temperature: 293
Thermo-optic coefficient
- dn/dT = -9.93e-05 K⁻¹
- k data cover 238-40000 nm only; k = 0 elsewhere in the n range 500-50000 nm
References
See also Crystran CsI online data sheet
Cite
Crystran Ltd. The Crystran handbook of infra-red and ultra-violet optical materials (5th edition, 2023); See also Crystran CsI online data sheet; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)
Data
Computed on 51 wavelengths, the same grid as the API and the library| λ (µm) | n | k |
|---|---|---|
| 0.5 | 1.8064 | 6.352857e-07 |
| 1 | 1.7572 | 5.467143e-07 |
| 2 | 1.7466 | 3.695714e-07 |
| 3 | 1.744 | 0 |
| 4 | 1.7431 | 0 |
| 5 | 1.7424 | 0 |
| 6 | 1.7418 | 0 |
| 7 | 1.7412 | 0 |
| 8 | 1.7406 | 0 |
| 9 | 1.7399 | 0 |
| 10 | 1.7392 | 0 |
| 11 | 1.7384 | 0 |
| 12 | 1.7375 | 0 |
| 13 | 1.7365 | 0 |
| 14 | 1.7355 | 0 |
| 15 | 1.7344 | 0 |
| 16 | 1.7332 | 0 |
| 17 | 1.7319 | 0 |
| 18 | 1.7306 | 0 |
| 19 | 1.7291 | 0 |
| 20 | 1.7276 | 0 |
| 21 | 1.726 | 0 |
| 22 | 1.7244 | 0 |
| 23 | 1.7226 | 0 |
| 24 | 1.7207 | 0 |
| 25 | 1.7188 | 0 |
| 26 | 1.7168 | 0 |
| 27 | 1.7147 | 0 |
| 28 | 1.7125 | 0 |
| 29 | 1.7101 | 0 |
| 30 | 1.7077 | 0 |
| 31 | 1.7052 | 0 |
| 32 | 1.7027 | 0 |
| 33 | 1.7 | 0 |
| 34 | 1.6972 | 0 |
| 35 | 1.6943 | 0 |
| 36 | 1.6913 | 0 |
| 37 | 1.6882 | 0 |
| 38 | 1.6849 | 0 |
| 39 | 1.6816 | 0 |
| 40 | 1.6781 | 0 |
| 41 | 1.6746 | 0 |
| 42 | 1.6709 | 0 |
| 43 | 1.6671 | 0 |
| 44 | 1.6631 | 0 |
| 45 | 1.6591 | 0 |
| 46 | 1.6549 | 0 |
| 47 | 1.6505 | 0 |
| 48 | 1.646 | 0 |
| 49 | 1.6414 | 0 |
| 50 | 1.6366 | 0 |
Optical transmission calculator
Free-standing sample in vacuum, normal incidence- Transmittance T
- —
- Reflectance R
- —
Fresnel reflection calculator
- Rp
- —
- Rs
- —
- R = (Rp+Rs)/2
- —
- Phase φp
- —
- Phase φs
- —
- Brewster angle θB
- —
- Critical angle θC
- —
Caesium Iodide is grown by sealed ampoule Stockbarger techniques with ingots of approximately 70mm diameter. CsI is very soft and pliable. IUPAC International Union of Pure and applied Chemistry recommends the spelling as Cesium. UK Useage is Caesium.
REFERENCES:
(1) Handbook Optical Constants, ed Palik, V2, ISBN 0-12-544422-2
(2) Rodney, J.Opt.Soc.Am. V45, p987, 1955
(3) Combes et al, J.Opt.Soc.Am. V41, p215, 1951
(4) Kelly, Bureau of Mines Bulletin, No371, p51, 1934