Optical constants
Refractive index of CdTe - Cadmium telluride (CRYSTRAN)
CdTe - Cadmium telluride: n,k 0.8–27.03 µm
- Data
- tabulated n + tabulated k
- Range
- 0.8–27.03 µm
- Points
- 19
- Temperature
- 300 K
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength. Note: k data cover 16000-38000 nm only; k = 0 elsewhere in the n range 800-27030 nm.
At one wavelength
- Refractive index n
- 2.68284
- Extinction coefficient k
- 0
- Permittivity ε1
- 7.19766
- Permittivity ε2
- 0
- Absorption coefficient α
- 0 cm⁻¹
- Penetration depth δ = λ/(2πk)
- — nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- 0.0033 µm⁻¹
- Group index ng
- 2.6675
- Group velocity dispersion
- — fs²/mm
- Dispersion parameter D
- — ps/(nm·km)
- Photon energy
- 0.266633 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
# CdTe - Cadmium telluride (CRYSTRAN): CdTe - Cadmium telluride
crystran_cdte = ls.fetch_refractiveindex("specs", "CRYSTRAN-optical", "CdTe", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(crystran_cdte.range_nm) # (800, 27030) nm
eps = crystran_cdte.eps([4650]) # 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_4b3f2ea7fec8/lightsmith"
crystran_cdte = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(crystran_cdte.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (crystran-cdte/crystran).
# ... load crystran_cdte as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=crystran_cdte)],
medium_index=1.0,
wavelengths=ls.WavelengthRange(start_nm=800, 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: 6200
- thermal dispersion
- type: constant, value: 5e-05
- thermal expansion
- value: 5.9e-06, temperature: 293
- hardness
- type: Knoop, value: 5.30e8
- melting point
- value: 1365
- thermal conductivity
- value: 6.2, temperature: 293
- youngs modulus
- value: 36.52e9
- poissons ratio
- value: 0.41
- solubility
- value: 0
Thermo-optic coefficient
- dn/dT = 5.00e-05 K⁻¹
- k data cover 16000-38000 nm only; k = 0 elsewhere in the n range 800-27030 nm
References
See also Crystran CdTe online data sheet
Cite
Crystran Ltd. The Crystran handbook of infra-red and ultra-violet optical materials (5th edition, 2023); See also Crystran CdTe 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 19 wavelengths, the same grid as the API and the library| λ (µm) | n | k |
|---|---|---|
| 0.8 | 2.876 | 0 |
| 1 | 2.84 | 0 |
| 2 | 2.713 | 0 |
| 2.5 | 2.702 | 0 |
| 3 | 2.695 | 0 |
| 3.5 | 2.691 | 0 |
| 4 | 2.6807 | 0 |
| 5 | 2.684 | 0 |
| 6 | 2.681 | 0 |
| 7 | 2.679 | 0 |
| 8 | 2.677 | 0 |
| 10 | 2.653 | 0 |
| 12.5 | 2.646 | 0 |
| 15.5 | 2.6407 | 0 |
| 20 | 2.614 | 0 |
| 22.2 | 2.601 | 1.080000e-05 |
| 24.8 | 2.5801 | 5.280000e-05 |
| 26.32 | 2.57 | 8.802000e-05 |
| 27.03 | 2.564 | 0.00010023 |
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
- —
CdTe is rarely used because of its toxicity. The finished optics are not particularly hazardous but should be handled with care. However, difficulties with processing cadmium compounds means that very few optical companies will cut and polish the material. Crystran Ltd does NOT supply CdTe. This data is provided for reference only. A form of CdTe was originally utilised as the obsolete Kodak designation of IRTRAN-6
CAUTION: Cadmium salts are TOXIC and should be handled with care.
REFERENCES:
(1) Handbook Optical Constants, ed Palik, V1, ISBN 0-12-544420-6
(2) NIST USA data
(3) Hawkins, Sherwood, Djotni: Mid IR Filters for astronomical and remote sensing instrumentation. Invited Paper SPIE Conference Glasgow 2008