2 research outputs found
Ultrastrong Coupling Enhancement with Squeezed Mode Volume in Terahertz Nanoslots
Metallic nanogaps have emerged as a versatile platform
for realizing
ultrastrong coupling in terahertz frequencies. Increasing the coupling
strength generally involved reducing the gap width to minimize the
mode volume, which presents challenges in fabrication and efficient
material coupling. Here, we propose employing terahertz nanoslots,
which can efficiently squeeze the mode volume in an extra dimension
alongside the gap width. Our experiments using 500 nm wide nanoslots
integrated with an organic–inorganic hybrid perovskite demonstrate
ultrastrong phonon–photon coupling with a record-high Rabi
splitting of 48% of the original resonance (Ω = 0.48ω0), despite having a gap width 5 times larger than previously
reported structures with Ω = 0.45ω0. Mechanisms
underlying this effective light–-matter coupling are investigated
with simulations using coupled mode theory. Moreover, bulk polariton
analyses reveal that our results account for 68% of the theoretical
maximum Rabi splitting, with the potential to reach 82% through further
optimization of the nanoslots
Temperature-Dependent Resonance Energy Transfer from Semiconductor Quantum Wells to Graphene
Resonance energy transfer (RET) has
been employed for interpreting
the energy interaction of graphene combined with semiconductor materials
such as nanoparticles and quantum-well (QW) heterostructures. Especially,
for the application of graphene as a transparent electrode for semiconductor
light emitting diodes, the mechanism of exciton recombination processes
such as RET in graphene-semiconductor QW heterojunctions should be
understood clearly. Here, we characterized the temperature-dependent
RET behaviors in graphene/semiconductor QW heterostructures. We then
observed the tuning of the RET efficiency from 5% to 30% in graphene/QW
heterostructures with ∼60 nm dipole–dipole coupled distance
at temperatures of 300 to 10 K. This survey allows us to identify
the roles of localized and free excitons in the RET process from the
QWs to graphene as a function of temperature