Ultra-small mode volume polariton condensation via precision He⁺ implantation

We present a novel method for generating potential landscapes in GaAs microcavities through focused He⁺ implantation. The ion beam imprints micron-scale patterns of non-radiative centers that deplete the exciton reservoir and form a loss-defined potential minimum. Under non-resonant pumping, the resulting traps have a lateral size ⩽1.2μm and a three-dimensional mode volume of only ≈0.6μm³, small enough to support a single polariton condensate mode. The implantation process maintains strong coupling and provides lithographic (<300nm) resolution. These loss-engineered traps effectively overcome the micrometer-scale limitations of conventional microcavity patterning techniques, opening new avenues for device development and polariton research within the sub-μm regime.