We present a compact and bichromatic imaging system, located outside of the vacuum chamber of a trapped ion apparatus, that collects the fluorescence of 230.6 nm and 369.5 nm photons simultaneously on a shared EMCCD camera. The system contains two lens doublets, consisting of a sphere and an asphere. It provides a numerical aperture of 0.45 and 0.40 at 230.6 nm and 369.5 nm, respectively, and enables spatially resolved state detection with a large field of view of 300 μm for long 115In+/172Yb+ Coulomb crystals. Instead of diffraction limited imaging for one wavelength, the focus in this system is on simultaneous single-ion resolved imaging of both species over a large field with special attention to the deep UV wavelength (230.6 nm) and the low scattering rate of In+ ions. The introduced concept is applicable to other dual-species applications.
@article{arxiv.2302.02489,
title = {Bichromatic UV detection system for atomically-resolved imaging of ions},
author = {T. Nordmann and S. Wickenhagen and M. Doležal and T. E. Mehlstäubler},
journal= {arXiv preprint arXiv:2302.02489},
year = {2023}
}