Atomic mercury vapor inside a hollow-core photonic crystal fiber

TL;DR

This paper demonstrates the successful containment of high-pressure atomic mercury vapor in a hollow-core photonic crystal fiber at room temperature, enabling strong optical nonlinearities in the ultraviolet spectrum.

Contribution

It introduces a method to fill and maintain high-pressure mercury vapor inside a kagomé-style hollow-core fiber, achieving significant optical depth without chemical activity issues.

Findings

Achieved an optical depth of 114 at the mercury transition

Maintained homogeneous vapor filling over several days

Demonstrated potential for ultraviolet nonlinear optics

Abstract

We demonstrate high atomic mercury vapor pressure in a kagom\'e-style hollow-core photonic crystal fiber at room temperature. After a few days of exposure to mercury vapor the fiber is homogeneously filled and the optical depth achieved remains constant. With incoherent optical pumping from the ground state we achieve an optical depth of 114 at the $6^3P_2 - 6^3D_3$ transition, corresponding to an atomic mercury number density of $6 \times 10^{10}$ cm$^{-3}$. The use of mercury vapor in quasi one-dimensional confinement may be advantageous compared to chemically more active alkali vapor, while offering strong optical nonlinearities in the ultraviolet region of the optical spectrum.