Sub-100 fs Formation of Dark Excitons in Monolayer WS.

Two-dimensional semiconducting transition metal dichalcogenides are promising materials for optoelectronic applications due to their strongly bound excitons. While bright excitons have been thoroughly scrutinized, dark excitons have been much less investigated, as they are not directly observable with far-field spectroscopy. However, with their nonzero momenta, dark excitons are significant for applications requiring long-range transport or coupling to external fields.

Light harvesting in purple bacteria does not rely on resonance fine-tuning in peripheral antenna complexes.

The ring-like peripheral light-harvesting complex 2 (LH2) expressed by many phototrophic purple bacteria is a popular model system in biological light-harvesting research due to its robustness, small size, and known crystal structure. Furthermore, the availability of structural variants with distinct electronic structures and optical properties has made this group of light harvesters an attractive testing ground for studies of structure-function relationships in biological systems. LH2 is one of several pigment-protein complexes for which a link between functionality and effects such as excitonic coherence and vibronic coupling has been proposed.

Neural-network-powered pulse reconstruction from one-dimensional interferometric correlation traces.

Any ultrafast optical spectroscopy experiment is usually accompanied by the necessary routine of ultrashort-pulse characterization. The majority of pulse characterization approaches solve either a one-dimensional (e.g.

Excited-State Dynamics in a DNA-Stabilized Ag Cluster with Near-Infrared Emission.

Due to desirable optical properties, such as efficient luminescence and large Stokes shift, DNA-templated silver nanoclusters (DNA-AgNCs) have received significant attention over the past decade. Nevertheless, the excited-state dynamics of these systems are poorly understood, as studies of the processes ultimately leading to a fluorescent state are scarce. Here we investigate the early time relaxation dynamics of a 16-atom silver cluster (DNA-AgNC) featuring NIR emission in combination with an unusually large Stokes shift of over 5000 cm.

Non-Hermitian Hamiltonians for linear and nonlinear optical response: A model for plexcitons.

In polaritons, the properties of matter are modified by mixing the molecular transitions with light modes inside a cavity. Resultant hybrid light-matter states exhibit energy level shifts, are delocalized over many molecular units, and have a different excited-state potential energy landscape, which leads to modified exciton dynamics. Previously, non-Hermitian Hamiltonians have been derived to describe the excited states of molecules coupled to surface plasmons (i.