Coherent enhancement of collection of light from linear ion crystals

TL;DR

This paper proposes a scheme to enhance photon collection from linear ion crystals using constructive interference, achieving over threefold improvement experimentally and offering potential for further enhancements with different ion species.

Contribution

The study introduces a coherent enhancement method for photon collection from linear ion crystals, validated experimentally and adaptable to various trap designs.

Findings

Experimental enhancement factor of 3.05 with nine ions

Numerical optimization for realistic ion positions

Potential for further improvements with different ion species

Abstract

The efficient detection of light from trapped ions in free space is paramount for most of their applications. We propose a scheme to enhance the photon collection from linear ion strings. It employs the constructive interference of light scattered from ions along the axial direction in linear Paul traps. The coherent enhancement of photon collection is numerically optimized for a range of feasible spatial angles and realistic ion positions in a single harmonic Coulomb potential. Despite the large mutual distance of scatterers on the order of many wavelengths of scattered light, presented experimental tests confirm the feasibility of enhancements by a factor of $3.05 \pm 0.09$ with a crystal of nine $^{40}$Ca$^+$ ions. Further significant improvements using different ion species, which allow for suppression of the sensitivity to the residual thermal motion, are predicted. The proposed collection geometry is intrinsic to diverse linear ion trap designs and the methodology can be directly applied to an observation of scattering from ion crystals prepared in collective electronic excitations.