Optical constants
Refractive index of CaF2 - Calcium fluoride (CRYSTRAN)
CaF2 - Calcium fluoride: n,k 0.149–9.429 µm
- Data
- tabulated n + tabulated k
- Range
- 0.149–9.429 µm
- Points
- 40
- State
- crystalline
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength.
At one wavelength
- Refractive index n
- 1.43391
- Extinction coefficient k
- 3.65556e-08
- Permittivity ε1
- 2.0561
- Permittivity ε2
- 1.04835e-07
- Absorption coefficient α
- 0.00781776 cm⁻¹
- Penetration depth δ = λ/(2πk)
- 2.55828e+09 nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- -0.0303922 µm⁻¹
- Group index ng
- 1.45177
- 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
# CaF2 - Calcium fluoride (CRYSTRAN): CaF2 - Calcium fluoride
crystran_caf2 = ls.fetch_refractiveindex("specs", "CRYSTRAN-optical", "CaF2", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(crystran_caf2.range_nm) # (149, 9429) nm
eps = crystran_caf2.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_2ece28809200/lightsmith"
crystran_caf2 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(crystran_caf2.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (crystran-caf2/crystran).
# ... load crystran_caf2 as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=crystran_caf2)],
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 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
- orientation
- o
Properties
- density
- value: 3180
- thermal dispersion
- type: constant, value: -1.06e-05
- thermal expansion
- value: 18.85e-06
- hardness
- type: Knoop, value: 1.55e9, indenter mass: 0.5
- melting point
- value: 1633
- thermal conductivity
- value: 9.71
- youngs modulus
- value: 75.8e9
- solubility
- value: 0.017
Thermo-optic coefficient
- dn/dT = -1.06e-05 K⁻¹
References
See also Crystran CaF2 online data sheet
Cite
Crystran Ltd. The Crystran handbook of infra-red and ultra-violet optical materials (5th edition, 2023); See also Crystran CaF2 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 40 wavelengths, the same grid as the API and the library| λ (µm) | n | k |
|---|---|---|
| 0.149 | 1.58 | 5.240000e-07 |
| 0.161 | 1.549 | 3.060000e-07 |
| 0.195 | 1.5 | 8.860000e-08 |
| 0.2 | 1.495 | 7.190000e-08 |
| 0.222 | 1.48 | 3.770000e-08 |
| 0.248 | 1.468 | 4.304708e-08 |
| 0.266 | 1.4621 | 4.270301e-08 |
| 0.28 | 1.4584 | 4.243540e-08 |
| 0.3 | 1.454 | 4.205310e-08 |
| 0.337 | 1.4481 | 4.134584e-08 |
| 0.4 | 1.4419 | 4.014159e-08 |
| 0.486 | 1.437 | 3.849770e-08 |
| 0.588 | 1.4339 | 3.654796e-08 |
| 0.656 | 1.4325 | 3.524814e-08 |
| 0.687 | 1.432 | 3.465558e-08 |
| 0.728 | 1.4314 | 3.387186e-08 |
| 0.884 | 1.4298 | 3.088991e-08 |
| 1.014 | 1.4288 | 2.840496e-08 |
| 1.1 | 1.4283 | 2.676106e-08 |
| 1.25 | 1.4275 | 2.389381e-08 |
| 1.65 | 1.4256 | 1.624779e-08 |
| 1.9 | 1.4244 | 1.146903e-08 |
| 2.058 | 1.4236 | 8.448850e-09 |
| 2.45 | 1.4214 | 9.557522e-10 |
| 2.7 | 1.4199 | 0 |
| 2.8 | 1.4192 | 0 |
| 3.05 | 1.4175 | 0 |
| 3.4 | 1.4149 | 0 |
| 4 | 1.4096 | 0 |
| 4.4 | 1.4057 | 0 |
| 4.8 | 1.4014 | 2.140000e-08 |
| 5 | 1.3991 | 7.620000e-08 |
| 5.304 | 1.3952 | 9.646000e-08 |
| 5.893 | 1.3871 | 3.023400e-07 |
| 6.483 | 1.3782 | 7.874000e-07 |
| 7.072 | 1.3681 | 2.153600e-06 |
| 7.661 | 1.357 | 5.974400e-06 |
| 8.251 | 1.3444 | 1.592600e-05 |
| 8.84 | 1.3308 | 3.846000e-05 |
| 9.429 | 1.3161 | 8.459000e-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
- —
Calcium Fluoride has widespread IR applications as spectroscopic CaF2 windows, CaF2 prisms and CaF2 lenses. Especially pure grades of Calcium Fluoride (CaF2) find useful applications in the UV and as UV Excimer laser windows. Calcium Fluoride (CaF2) is available doped with Europium as a gamma-ray scintillator.
Calcium fluoride (CaF2 or fluorite) is grown by vacuum Stockbarger technique in diameters of up to about 250mm.
Crystal for infrared use is often grown using naturally mined fluorite to reduce costs. It will not have the best transmission in the UV and VUV and can have absorption bands at 300nm due to impurities.
For UV and VUV applications chemically prepared raw material is generally used. For Excimer applications, we use only the highest grade of specially selected material and crystal.
REFERENCES:
(1) Handbook Optical Constants, ed Palik, V2, ISBN 0-12-544422-2
(2) Dressler et al., Cryst.Res.Technol. V27, p413, 1992
(3) I.H.Malitson; J.Opt.Soc.Am. Vol52, p1377, 1962
(4) Ballard et al; Rev. Sci. Instr., V21, p905, 1950 also OSA PUBLISHING
(5) Batchelder & Simmons, J.Chem. Phys. V41, p2324 N8 1964
(6) Schumann & Neumann, Crys. Res. Tech V19, 1984
(7) Dickinson, IR laser windows, AFCRL-TR-0318, Air Force, Cambridge 1975