Refractive index database

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Optical constants of Ar (Argon)
Bideau-Mehu et al. 1981: n 0.140–0.568 µm

Wavelength: µm

Complex refractive index (n+ik)[ i ]

n   k   LogX   LogY   eV

Derived optical constants

Dispersion formula


Conditions & Spec sheet

n_is_absolute: true
temperature: 0 °C
pressure: 101325 Pa


Standard conditions. 0 °C, 760 torr (101.325 kPa).


1) A. Bideau-Mehu, Y. Guern, R. Abjean, A. Johannin-Gilles. Measurement of refractive indices of neon, argon, krypton and xenon in the 253.7-140.4 nm wavelength range. Dispersion relations and estimated oscillator strengths of the resonance lines. J. Quant. Spectrosc. Rad. Transfer 25, 395-402 (1981)

2) T. Larsén. Beitrag zur Dispersion der Edelgase. Z. Physik 88, 389-394 (1934)

* Sellmeier formula is derived by the authors of ref. 1 using their own data in the 0.1404-0.2537 μm range combined with data from ref. 2 at longer wavelengths.


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Argon, Ar

Argon (Ar) is a noble gas with an atomic number of 18, and it's one of the most abundant gases in the Earth's atmosphere. It is colorless, odorless, and generally chemically inert, conforming to the behavior of noble gases. In the optical domain, argon is best known for its applications in gas lasers, specifically argon-ion lasers, which emit light in the ultraviolet to visible range. These lasers are employed in a variety of applications, from scientific research to medical procedures and even in some types of laser light shows. Argon is also commonly used as a shielding gas in various types of arc welding, as its inert properties prevent the oxidation of metal being welded. In low-temperature applications, liquid argon serves as a cryogen, and in specialized optical applications, it can be used as a fill gas for windows or other optical elements to prevent fogging and reduce thermal conduction. Although argon is not notable for any particularly strong optical absorption or emission features in the bulk phase, its stable and inert nature makes it a versatile component in a variety of optical and industrial applications.

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