Optical constants
Refractive index of CsBr - Caesium bromide (CRYSTRAN)
CsBr - Caesium bromide: n,k 0.5–39 µm
- Data
- tabulated n + tabulated k
- Range
- 0.5–39 µm
- Points
- 39
- Temperature
- 300 K
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength.
At one wavelength
- Refractive index n
- 1.70352
- Extinction coefficient k
- 2.14121e-07
- Permittivity ε1
- 2.90199
- Permittivity ε2
- 7.29521e-07
- Absorption coefficient α
- 0.0457918 cm⁻¹
- Penetration depth δ = λ/(2πk)
- 4.36759e+08 nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- -0.06206 µm⁻¹
- Group index ng
- 1.73999
- 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
# CsBr - Caesium bromide (CRYSTRAN): CsBr - Caesium bromide
crystran_csbr = ls.fetch_refractiveindex("specs", "CRYSTRAN-optical", "CsBr", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(crystran_csbr.range_nm) # (500, 39000) nm
eps = crystran_csbr.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_a2e29dde01bd/lightsmith"
crystran_csbr = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(crystran_csbr.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (crystran-csbr/crystran).
# ... load crystran_csbr as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=crystran_csbr)],
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
Conditions
- temperature
- 300 K
Properties
- density
- value: 4400
- thermal dispersion
- type: constant, value: 8.4e-05, wavelength: 0.6e-6
- thermal expansion
- value: 47.9e-06, temperature: 273
- hardness
- type: Knoop, value: 1.91e8
- melting point
- value: 909
- thermal conductivity
- value: 0.94, temperature: 273
- youngs modulus
- value: 15.85e9
- poissons ratio
- value: 0.279
- solubility
- value: 420, temperature: 284; value: 560, temperature: 288; value: 900, temperature: 298; value: 980, temperature: 300; value: 1020, temperature: 301.5; value: 1180, temperature: 304; value: 1380, temperature: 308
Thermo-optic coefficient
- dn/dT = 8.40e-05 K⁻¹ at 600 nm
References
See also Crystran CsBr online data sheet
Cite
Crystran Ltd. The Crystran handbook of infra-red and ultra-violet optical materials (5th edition, 2023); See also Crystran CsBr 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 39 wavelengths, the same grid as the API and the library| λ (µm) | n | k |
|---|---|---|
| 0.5 | 1.70896 | 2.173333e-07 |
| 1 | 1.67793 | 1.990000e-07 |
| 2 | 1.67061 | 1.623333e-07 |
| 3 | 1.66901 | 0 |
| 4 | 1.66813 | 0 |
| 5 | 1.66737 | 0 |
| 6 | 1.66659 | 0 |
| 7 | 1.66573 | 0 |
| 8 | 1.66477 | 0 |
| 9 | 1.6637 | 0 |
| 10 | 1.66251 | 0 |
| 11 | 1.6612 | 0 |
| 12 | 1.65976 | 0 |
| 13 | 1.6582 | 0 |
| 14 | 1.6561 | 0 |
| 15 | 1.65468 | 0 |
| 16 | 1.65272 | 0 |
| 17 | 1.65062 | 0 |
| 18 | 1.64838 | 0 |
| 19 | 1.646 | 0 |
| 20 | 1.64348 | 0 |
| 21 | 1.6408 | 0 |
| 22 | 1.63798 | 0 |
| 23 | 1.635 | 0 |
| 25 | 1.62856 | 0 |
| 26 | 1.62509 | 2.495099e-08 |
| 27 | 1.62146 | 4.990199e-08 |
| 28 | 1.61764 | 7.485298e-08 |
| 29 | 1.61365 | 9.819551e-07 |
| 30 | 1.60947 | 3.063202e-06 |
| 31 | 1.6051 | 5.144450e-06 |
| 32 | 1.60053 | 7.225697e-06 |
| 33 | 1.59576 | 9.306945e-06 |
| 34 | 1.59078 | 1.665299e-05 |
| 35 | 1.58558 | 2.662749e-05 |
| 36 | 1.58016 | 3.660199e-05 |
| 37 | 1.5745 | 4.657650e-05 |
| 38 | 1.5686 | 5.655100e-05 |
| 39 | 1.56245 | 6.652550e-05 |
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 Bromide is grown by sealed ampoule Stockbarger technique. CsBr is a soft pliable material. IUPAC International Union of Pure and applied Chemistry recommends the spelling as Cesium. UK Useage is Caesium. Solubility has historically been quoted as 124g/100mL at 25°C but Crystran Ltd tests 2021 have found this to be inaccurate.
REFERENCES:
(1) Handbook Optical Constants, ed Palik, V3, ISBN 0-12-544423-0
(2) Mitsuishi et al., J Opt Soc. Am. V52, p14, 1962
(3) Kelly, Bureau of Mines Bulletin, No371, p51, 1934
(4) S.Ballard et al; J.Opt.Soc.Am. Vol42, p684, 1952
(5) H.H.Li; J.Phys. Chem. Ref. Data. Vol 5, No 2. 1976
(6) K.Matthews. Crystran Ltd Test Data 2021