A 3.4- $\mu \text{m}$ -Sized Atmospheric-Pressure Nonequilibrium Microplasma Array With High Aspect Ratio and High Electron Density

In this paper, we demonstrate an atmospheric-pressure nonequilibrium Ar microplasma array confined inside photonic crystal fiber for the first time. The diameter and the length of each microplasma plume are 3.4 μm and 2 cm, respectively. The electron density evaluated from the Stark effect of Ar spectral line is up to 8 × 10
¹⁶
cm
^-3
. The electron temperature calculated by the Ar collisional-radiative model is 0.85 eV, while the gas temperature obtained by fitting the N
₂
rotational spectrum is 500 K.