Vectorial probing of electric and magnetic transitions in variable optical environments and vice-versa

TL;DR

This paper investigates electric and magnetic transitions in europium-doped nanorods, analyzing their optical responses and local density of states modifications near a mirror, revealing orientation sensitivities and intrinsic emitter properties.

Contribution

It introduces a method to probe electric and magnetic dipole contributions in nanorods and determines their intrinsic properties through combined experimental and simulation approaches.

Findings

Significant orientation sensitivity of electric and magnetic transition ratios.

Determination of dipole orientation and oscillator strength of emitters.

Observation of LDOS modifications near a gold mirror affecting emission properties.

Abstract

We use europium doped single crystalline NaYF$_4$ nanorods for probing the electric and magnetic contributions to the local density of optical states (LDOS). Reciprocically, we determine intrinsic properties of the emitters (oscillator strength, quantum yield) by comparing their measured and simulated optical responses in front of a mirror. We first experimentally determine the specifications of the nanoprobe (orientation and oscillator strength of the electric and magnetic dipoles moments) and show significant orientation sensitivity of the branching ratios associated with electric and magnetic transitions. In a second part, we measure the modification of the LDOS in front of a gold mirror in a Drexhage's experiment. We discuss the role of the electric and magnetic LDOS on the basis of numerical simulations, taking into account the orientation of the dipolar emitters. We demonstrate that they behave like degenerated dipoles sensitive to polarized partial LDOS.