  Realizing lattices of exciton polariton condensates has been of much interest
owing to the potential of such systems to realize analog Hamiltonian simulators
and physical computing architectures. Prior work on polariton condensate
lattices has primarily been on GaAs-based systems, with the recent advent of
organic molecules and perovskite systems allowing room-temperature operation.
However, in most of these room temperature systems, the lattices are defined
using a bottom-up approach by patterning the bottom mirrors, significantly
limiting the types of lattices and refractive index contrast that can be
realized. Here, we report a direct write approach that uses a Focused Ion Beam
(FIB) to etch 2D lattice into a planar microcavity. Such etching of the cavity
allows for realizing high refractive index contrast lattices. We realize the
polariton condensate lattice using the highly photostable host-guest Frenkel
excitons of an organic dye small molecular ionic lattice (SMILES).1,2 The
lattice structures are defined on a planar microcavity embedded with SMILES
using FIB, allowing the realization of lattices with different geometries,
including defect sites on demand. The band structure of the lattice and the
emergence of condensation are imaged using momentum-resolved spectroscopy. The
present approach allows us to study periodic, quasi-periodic, and disordered
polariton condensate lattices at room temperature using a top-down approach
without compromising on the quantum yield of the organic excitonic material
embedded in the cavity.
