Quantitatively characterize collection efficiency using cryogenic BFP imaging

Quantify the photon collection efficiency of the fabricated cryogenic metallo-dielectric antenna, preferably including the design with a 100-nm silica solid-immersion-lens spacer, through a complete experimental characterization rather than inference from a best-fitting simulation.

Background

The paper infers a 79% collection efficiency from the simulated configuration that best matches a measured back-focal-plane image. Because the emitter position, dipole orientation, and crystal orientation are not independently known, this value is not a direct measurement. The authors identify a full experimental characterization as work that remains unresolved.

References

It nonetheless represents a first step toward a full experimental characterization of the collection efficiency, which we leave to future work.

— Designing metallo-dielectric antennas for cryogenic applications  (2609.11809 - Luo et al., 10 Sep 2026) in Section 4, “Back-focal-plane imaging of a single molecule inside the antenna at cryogenic temperature”

For the vertical component, however, the corresponding feature -- its outer-ring maximum -- lies at large angles and may be truncated by the NA accessible in our setup. As we cannot tell whether, and how much of, this maximum is cut off, the refractive index experienced by the vertical component cannot be determined with the same confidence but needs to be estimated, which makes it difficult to identify the matching simulation unambiguously.

— Designing metallo-dielectric antennas for cryogenic applications  (2609.11809 - Luo et al., 10 Sep 2026) in Section 4, “Back-focal-plane imaging of a single molecule inside the antenna at cryogenic temperature”