Optical constants
Refractive index of C - Diamond (CRYSTRAN)
C - Diamond: n,k 0.232–20 µm
- Data
- tabulated n + tabulated k
- Range
- 0.232–20 µm
- Points
- 13
- State
- polycrystalline
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength. Note: k data cover 240-24800 nm only; k = 0 elsewhere in the n range 232-20000 nm.
At one wavelength
- Refractive index n
- 2.41784
- Extinction coefficient k
- 1.90600e-06
- Permittivity ε1
- 5.84597
- Permittivity ε2
- 9.21682e-06
- Absorption coefficient α
- 0.407616 cm⁻¹
- Penetration depth δ = λ/(2πk)
- 4.90658e+07 nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- -0.245109 µm⁻¹
- Group index ng
- 2.56187
- 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
# C - Diamond (CRYSTRAN): C - Diamond
crystran_diamond = ls.fetch_refractiveindex("specs", "CRYSTRAN-optical", "diamond", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(crystran_diamond.range_nm) # (232, 20000) nm
eps = crystran_diamond.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_2e16ed76aacc/lightsmith"
crystran_diamond = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(crystran_diamond.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (crystran-diamond/crystran).
# ... load crystran_diamond as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=crystran_diamond)],
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
Properties
- density
- value: 3510
- thermal dispersion
- type: constant, value: 9.6e-06
- thermal expansion
- value: 1.0e-06, temperature: 293
- hardness
- type: Knoop, value: 5.59e10
- melting point
- value: 3770
- thermal conductivity
- value: 2600, temperature: 273
- youngs modulus
- value: 1.050e12
- poissons ratio
- value: 0.16
- solubility
- value: 0
Thermo-optic coefficient
- dn/dT = 9.60e-06 K⁻¹
- k data cover 240-24800 nm only; k = 0 elsewhere in the n range 232-20000 nm
References
See also Crystran Diamond online data sheet
Cite
Crystran Ltd. The Crystran handbook of infra-red and ultra-violet optical materials (5th edition, 2023); See also Crystran Diamond 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 13 wavelengths, the same grid as the API and the library| λ (µm) | n | k |
|---|---|---|
| 0.232 | 2.6917 | 0 |
| 0.298 | 2.5429 | 2.230000e-06 |
| 0.405 | 2.4626 | 2.845000e-06 |
| 0.589 | 2.4175 | 1.915000e-06 |
| 0.656 | 2.4104 | 1.740000e-06 |
| 1 | 2.3905 | 8.080859e-07 |
| 2 | 2.3813 | 6.516442e-07 |
| 3 | 2.3795 | 4.110000e-05 |
| 4 | 2.3787 | 0.000173 |
| 5 | 2.3783 | 0.000585 |
| 6 | 2.3779 | 8.040000e-05 |
| 10 | 2.3765 | 2.390000e-05 |
| 20 | 2.3741 | 4.040000e-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
- —
Diamond is used for transmission windows and domes, and offers a very wide transmission range. Type IIa is the hardest material available and has the highest thermal conductivity.
Diamond is available as single crystal (Type IIa) natural or synthetic or as polycrystalline CVD film. Single crystal is available economically up to about 4mm diameter. CVD diamond of 75mm diameter is available.
The IR transmission has a range of absorptions in the mid-IR between 2,5 and 7 microns due to inherent lattice resonances. The UV transmission may be limited to 350nm in poorer quality samples.
Single crystal diamond is selected into four forms:
Ia ~98% of natural yield (>100ppm Nitrogen - yellow)
Ib ~0.1% of natural yield (~100ppm Nitrogen)
IIa ~2% of natural yield (1ppm Nitrogen)
IIb - Synthetic only (100ppm boron for electronic applications)
Only Type IIa is used for optical applications. CVD diamond transmission and characteristics are very similar to Type IIa.
Being a form of carbon, diamond oxidises in air over 700°C. In the absence of oxygen such as in a flow or argon gas, diamond can be heated to 1700°C. The surface blackens but can be recovered by polishing.
REFERENCES:
(1) Handbook Optical Constants, ed Palik, V1, ISBN 0-12-544420-6
(2) Properties Polycrystalline Diamond, Sussmann et. al. Diamond & Rel. Mat. 3(1994) 303-312
(3) Fontenella et. al. App. Optics 16, 2949 (1977)
(4) Slack & Bartram J.Appl. Phys. 46, 89 (1975)