Laser spectroscopy of the 1001nm ground state transition in dysprosium

TL;DR

This study reports the first direct laser excitation of the ultra-narrow 1001 nm ground state transition in dysprosium, measuring isotopic shifts, confirming level energies, and estimating the excited state's lifetime for high-precision spectroscopy.

Contribution

It provides the first direct excitation and detailed spectroscopic measurements of the 1001 nm transition in dysprosium, including isotopic shifts and lifetime estimates.

Findings

Measured isotopic shifts for all seven stable isotopes.

Confirmed the upper level energy as 9991.004(1) cm⁻¹.

Estimated a lower limit of 2.9(1) μs for the excited state lifetime.

Abstract

We present the first direct excitation of the presumably ultra-narrow $1001 \, \textrm{nm}$ ground state transition in atomic dysproium. By using resonance ionization spectroscopy with pulsed Ti:sapphire lasers at a hot cavity laser ion source, we were able to measure the isotopic shifts in the $1001 \, \textrm{nm}$ line between all seven stable isotopes. Furthermore, we determined the upper level energy from the atomic transition frequency of the $^{164} \textrm{Dy}$ isotope as $9991.004(1) \, \textrm{cm}^{-1}$ and confirm the level energy listed in the NIST database. Since a sufficiently narrow natural linewidth is an essential prerequisite for high precision spectroscopic investigations for fundamental questions we furthermore determined a lower limit of $2.9(1) \, \mu\textrm{s}$ for the lifetime of the excited state.