He (Helium)

5 datasets, together covering 0.09–2.059 µm. Default: Börzsönyi et al. 2008: n 0.4–1.0 µm.

Compare datasets

Tick datasets in the list to add them to the plot (up to 12).

Datasets

Use it in Lightsmith

Load this data in Python, simulate in one more line

pip install lightsmith

import lightsmith as ls

# He (Helium): Börzsönyi et al. 2008: n 0.4–1.0 µm
he = ls.fetch_refractiveindex("main", "He", "Borzsonyi", ref="c5c2f188e848453def5970e347399d653df2ffc2")
print(he.range_nm)  # (400, 1000) nm
eps = he.eps([633])  # complex permittivity

Downloads 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_4883368e64cb/lightsmith"
he = ls.Tabulated.model_validate(json.load(urllib.request.urlopen(url)))
print(he.source)  # citation and provenance travel with the data

Any dataset here, as the library's Tabulated material (he/borzsonyi-2008).

# ... load he as above, then:
sim = ls.Simulation(
    particles=[ls.Particle(shape=ls.Sphere(radius_nm=50), material=he)],
    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 wavelength

Same spec runs with DDA, FDTD, BEM or T-matrix: ls.compare(sim, ["mie", "dda"]).

import json, urllib.request
import lightsmith as ls

url = "https://materials.lightsmith.dev/v1/datasets/ds_4883368e64cb/lightsmith?model=drude_lorentz"
he_dl = ls.DrudeLorentz.model_validate(json.load(urllib.request.urlopen(url)))

A dispersive Drude–Lorentz model for time-domain solvers.

Materials guide Open a sphere of it in Studio Quick start Ask the community

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.

About He (Helium)

Helium (He) is a noble gas that is colorless, odorless, and tasteless. In the realm of optics, helium is frequently employed as a buffer gas in gas lasers such as helium-neon (He-Ne) and carbon dioxide (CO₂) lasers. In He-Ne lasers, helium helps to excite neon atoms, thereby facilitating the laser action, while in CO₂ lasers, it assists in the quick dissipation of heat. Additionally, helium's low refractive index, which is close to that of a vacuum, makes it useful in interferometry and other precision measurement techniques. Outside of optics, helium is commonly used in cryogenic environments to achieve extremely low temperatures, which are essential for certain high-precision devices like superconducting magnets used in Magnetic Resonance Imaging (MRI). Despite being one of the most abundant elements in the universe, its applications are quite diverse.

Other names: Helium

API: /v1/materials/mat_27fdf82b4628 · slug he