Abstract:
Probing light-matter interaction is at the heart of nanophotonics. Studying the interaction
of light with molecular emitters have wide implications including applications
like developing molecular probes for sensing, molecular antennas etc. To achieve
control over the molecular emission and harness it, one has to modulate emission parameters
like intensity, wavevectors, and polarization of the molecular emitter. In this
context, various cavity architectures have been studied to manipulate molecular emission.
Design of cavity architectures play a very critical role in tailoring the emission
properties from the cavity. Architectures based on metallic nanostructures, dielectric
resonators, hybrid metal-dielectric cavities can be used to tailor specific parameters
of light-matter interaction effectively. Metal film based cavities have emerged as an
important design architecture in the recent times. This design facilitates flexibility to
create both metal and metal-hybrid based cavities. In the past, intensity enhancement
of molecular emission in cavities has been studied extensively. But the effect of cavity
on wavevector distribution and polarization of molecular emission signatures have not
been studied in great detail. Understanding them, potentially, can give rich information
about the coupling strength of the interaction, modes of the cavity and much more. It
can also be used to efficiently design cavities focusing on antenna aspect of the cavity
design.
Herein, we discuss the effect of different metal film based cavities on the wavevector
and polarization states of the molecular emission coupled to them. We probe various
metal-dielectric hybrid cavities using Fourier plane imaging and spectroscopy. First, we
discuss the effect of an elongated cavity created using plasmonic nanowire placed on
gold film on the wavevector signatures of molecules sandwiched between the wire and
the film. We discuss the effect of such extremely small cavities on different relaxation
process like Raman scattering and molecular fluorescence. Next we present the effect
of vertical molecular nanowire cavity coupled to thin plasmonic film on its emission
pattern as a function of operational wavelength. Finally, we will discuss the effect
of microsphere cavity placed on metal film on wavevector and polarization states of
molecular emission.
