Optical constants
Refractive index of BD-2 (LightPath)
BD-2: n,k 3–14 µm
- Data
- tabulated nk
- Range
- 3–14 µm
- Points
- 12
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength.
At one wavelength
- Refractive index n
- 2.613
- Extinction coefficient k
- 5.15660e-07
- Permittivity ε1
- 6.82777
- Permittivity ε2
- 2.69484e-06
- Absorption coefficient α
- 0.00999996 cm⁻¹
- Penetration depth δ = λ/(2πk)
- 2.00001e+09 nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- -0.0025 µm⁻¹
- Group index ng
- 2.6292
- Group velocity dispersion
- — fs²/mm
- Dispersion parameter D
- — ps/(nm·km)
- Photon energy
- 0.191334 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
# BD-2 (LightPath): BD-2
lightpath_bd_2 = ls.fetch_refractiveindex("specs", "LightPath-infrared", "BD-2", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(lightpath_bd_2.range_nm) # (3000, 14000) nm
eps = lightpath_bd_2.eps([6480]) # 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_d38b675d7e12/lightsmith"
lightpath_bd_2 = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(lightpath_bd_2.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (lightpath-bd-2/lightpath).
# ... load lightpath_bd_2 as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=lightpath_bd_2)],
medium_index=1.0,
wavelengths=ls.WavelengthRange(start_nm=3000, stop_nm=14000, 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: 4670
- hardness
- type: Knoop, value: 1.47e9
- youngs modulus
- value: 22.1e9
- thermal expansion
- value: 14e-06
- thermal dispersion
- type: dn/dT, value: 91e-6
- transformation temperature
- value: 551
Thermo-optic coefficient
- dn/dT = 9.10e-05 K⁻¹
References
Cite
BD-2 Glass Datasheet (revision 2013-05); Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)
Data
12 rows as published| λ (µm) | n | k |
|---|---|---|
| 3.0 | 2.6266 | 2.387e-07 |
| 4.0 | 2.621 | 3.183e-07 |
| 5.0 | 2.6173 | 3.979e-07 |
| 6.0 | 2.6142 | 4.775e-07 |
| 7.0 | 2.6117 | 5.57e-07 |
| 8.0 | 2.6088 | 6.366e-07 |
| 9.0 | 2.6055 | 7.162e-07 |
| 10.0 | 2.6023 | 7.958e-07 |
| 11.0 | 2.5983 | 2.626e-06 |
| 12.0 | 2.5942 | 1.241e-05 |
| 13.0 | 2.5892 | 2.069e-05 |
| 14.0 | 2.5843 | 2.228e-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
- —
All values represent glass characteristics after molding