Tip-enhanced photoluminescence (TRPL) is a powerful technique
for
spatially and spectrally probing local optical properties of 2-dimensional
(2D) materials that are modulated by the local heterogeneities, revealing
inaccessible dark states due to bright state overlap in conventional
far-field microscopy at room temperature. While scattering-type near-field
probes have shown the potential to selectively enhance and reveal
dark exciton emission, their technical complexity and sensitivity
can pose challenges under certain experimental conditions. Here, we
present a highly reproducible and easy-to-fabricate near-field probe
based on nanoimprint lithography and fiber-optic excitation and collection.
The novel near-field measurement configuration provides an ∼3
orders of magnitude out-of-plane Purcell enhancement, diffraction-limited
excitation spot, and subdiffraction hyperspectral imaging resolution
(below 50 nm) of dark exciton emission. The effectiveness of this
high spatial XDmapping technique was then demonstrated
through reproducible hyperspectral mapping of oxidized sites and bubble
areas.