Optical constants
Refractive index of Cs (Caesium)
Monin and Boutry 1974: n,k 0.254–0.620 µm; 195 K
- Data
- tabulated nk
- Range
- 0.2536–0.62 µm
- Points
- 14
- Temperature
- 195 K
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength.
At one wavelength
- Refractive index n
- 0.248171
- Extinction coefficient k
- 1.06397
- Permittivity ε1
- -1.07045
- Permittivity ε2
- 0.528095
- Absorption coefficient α
- 227540 cm⁻¹
- Penetration depth δ = λ/(2πk)
- 87.8966 nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- -0.190476 µm⁻¹
- Group index ng
- 0.360095
- 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
# Cs (Caesium): Monin and Boutry 1974: n,k 0.254–0.620 µm; 195 K
cs = ls.fetch_refractiveindex("main", "Cs", "Monin", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(cs.range_nm) # (253.6, 620) nm
eps = cs.eps([397]) # 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_ac776903fd12/lightsmith"
cs = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(cs.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (cs/monin-boutry-1974).
# ... load cs as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=cs)],
medium_index=1.0,
wavelengths=ls.WavelengthRange(start_nm=400, stop_nm=620, 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
- 195 K
References
- doi:10.1103/physrevb.9.1309 Optical and photoelectric properties of alkali metals, Physical Review B (1974)
Cite
J. Monin and G. -A. Boutry. Optical and photoelectric properties of alkali metals. Physical Review B, 9, 1309-1327 (1974), doi:10.1103/physrevb.9.1309; Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)
Data
14 rows as published| λ (µm) | n | k |
|---|---|---|
| 0.2536 | 0.907 | 0.157 |
| 0.2654 | 0.893 | 0.167 |
| 0.2804 | 0.876 | 0.173 |
| 0.3025 | 0.836 | 0.18 |
| 0.334 | 0.761 | 0.197 |
| 0.366 | 0.667 | 0.233 |
| 0.406 | 0.533 | 0.318 |
| 0.4358 | 0.432 | 0.426 |
| 0.46 | 0.368 | 0.533 |
| 0.4916 | 0.315 | 0.678 |
| 0.51 | 0.297 | 0.756 |
| 0.546 | 0.269 | 0.906 |
| 0.578 | 0.25 | 1.029 |
| 0.62 | 0.242 | 1.182 |
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
- —
195 K (-78.15 °C)