Optical constants
Refractive index of V-Ga (Vanadium-gallium alloy)
Golovashkin et al. 1970: n,k 0.45–2.6 µm; 78 K
- Data
- tabulated nk
- Range
- 0.45–2.6 µm
- Points
- 32
- Temperature
- 78 K
- Licence
- CC0-1.0
Plot
Click the plot to set the calculator wavelength.
At one wavelength
- Refractive index n
- 2.4252
- Extinction coefficient k
- 3.55536
- Permittivity ε1
- -6.75899
- Permittivity ε2
- 17.2449
- Absorption coefficient α
- 760347 cm⁻¹
- Penetration depth δ = λ/(2πk)
- 26.3038 nm
- Abbe number Vd
- —
- Chromatic dispersion dn/dλ
- 2 µm⁻¹
- Group index ng
- 1.25
- 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
# V-Ga (Vanadium-gallium alloy): Golovashkin et al. 1970: n,k 0.45–2.6 µm; 78 K
v_ga = ls.fetch_refractiveindex("other", "V-Ga", "Golovashkin-78K", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(v_ga.range_nm) # (450, 2600) nm
eps = v_ga.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_17f45d05b296/lightsmith"
v_ga = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(v_ga.source) # citation and provenance travel with the dataAny dataset here, as the library's Tabulated material (v-ga/golovashkin-1970-78k).
# ... load v_ga as above, then:
sim = ls.Simulation(
particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=v_ga)],
medium_index=1.0,
wavelengths=ls.WavelengthRange(start_nm=450, 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
- 78 K
References
Cite
A. I. Golovashkin, I. S. Levchenko and G. P. Motulevich. Optical properties and electron characteristics of vanadium-gallium alloys obtained by evaporation in vacuum, Sov. Phys. JETP 30, 44-48 (1970); Data from the refractiveindex.info database (M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2)
Data
32 rows as published| λ (µm) | n | k |
|---|---|---|
| 0.45 | 1.96 | 3.09 |
| 0.5 | 2.24 | 3.36 |
| 0.55 | 2.35 | 3.42 |
| 0.6 | 2.45 | 3.6 |
| 0.65 | 2.65 | 3.68 |
| 0.7 | 2.82 | 3.99 |
| 0.74 | 3.06 | 3.9 |
| 0.76 | 3.12 | 3.98 |
| 0.8 | 3.26 | 4.0 |
| 0.85 | 3.27 | 4.01 |
| 0.9 | 3.45 | 4.16 |
| 0.95 | 3.5 | 4.16 |
| 0.98 | 3.49 | 4.24 |
| 1.0 | 3.55 | 4.33 |
| 1.04 | 3.58 | 4.31 |
| 1.07 | 3.6 | 4.34 |
| 1.1 | 3.63 | 4.37 |
| 1.2 | 3.94 | 4.61 |
| 1.3 | 4.16 | 4.67 |
| 1.4 | 4.35 | 4.76 |
| 1.5 | 4.3 | 4.94 |
| 1.6 | 4.35 | 5.16 |
| 1.7 | 4.44 | 5.28 |
| 1.8 | 4.32 | 5.24 |
| 1.9 | 4.22 | 5.71 |
| 2.0 | 4.47 | 6.16 |
| 2.1 | 4.48 | 6.32 |
| 2.2 | 4.58 | 6.56 |
| 2.3 | 4.61 | 6.86 |
| 2.4 | 4.74 | 6.66 |
| 2.5 | 4.79 | 6.78 |
| 2.6 | 4.95 | 7.1 |
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
- —
78 K (-195.15 °C). Avaraged data for samples containing 37, 33, and 6 wt% gallium (optical constants of the three samples are close to one another).