相关论文: Ultrafast Collective Excited State Dynamics of a V…
Concentration quenching is a well-known challenge in many fluorescence imaging applications. Here we show that the optical emission from hundreds of chromophores confined onto the surface of a virus particle 28 nm diameter can be recovered…
Ultrafast laser excitation can create coherent superpositions of electronic states in molecules and trigger ultrafast flow of electron density on few- to sub-femtosecond time scales. While recent attosecond experiments have addressed…
Photosynthesis relies on efficient energy relaxation within the excited-state manifold of pigment-protein complexes. Since the protein scaffold is rather flexible, the resulting energetic and structural disorder gives rise to a complex…
Ultrafast optical pump-probe spectroscopy measurement on monolayer graphene observes significant optical nonlinearities. We show that strongly photoexcited graphene monolayers with 35 fs pulses quasi-instantaneously build up a broadband,…
Intersystem crossings between singlet and triplet states represent a crucial relaxation pathway in photochemical processes. Herein, we probe the intersystem crossing in hexafluoro-acetylacetone with ultrafast X-ray transient absorption…
Dissipation of electromagnetic energy through absorption is a fundamental process that underpins phenomena ranging from photovoltaics to photography, analytical spectroscopy, photosynthesis, and human vision. Absorption is also a dynamic…
In this paper we consider dynamics of a molecular system subjected to external pumping by a light source. Within a completely quantum mechanical treatment, we derive a general formula, which enables to asses effects of different light…
Fast radio bursts (FRBs) are bright radio transients with short durations and extremely high brightness temperatures, and their physical origins are still unknown. Recently, a repeating source, FRB 20200120E, was found in a globular cluster…
The effect of thermal shape fluctuations on the recurrent fluorescence of boron cluster cations, B$_N^+$ ($N=9-14$), has been investigated numerically, with a special emphasis on B$_{13}^+$. For this cluster, the electronic structures of…
We study ultra-broadband slow light in a warm Rubidium vapor cell. By working between the D1 and D2 transitions, we find a several-nm window centered at 788.4 nm in which the group index is highly uniform and the absorption is small (<1%).…
We report a comprehensive study of ultrafast carrier dynamics in single crystals of multiferroic BiFeO$_{3}$. Using femtosecond optical pump-probe spectroscopy, we find that the photoexcited electrons relax to the conduction band minimum…
We investigate the optical absorption and transmission of few-layer phosphorene in the framework of ab initio density functional simulations and many-body perturbation theory at the level of random phase approximation. In bilayer…
We investigate the dynamics of molecular photoexcitation by unchirped femtosecond laser pulses using RbCs as a model system. This study is motivated by a goal of optimizing a two-color scheme of transferring vibrationally-excited ultracold…
Twisted bilayer graphene with tiny rotation angles have drawn significant attention due to the observation of the unconventional superconducting and correlated insulating behaviors. In this paper, we employ a full tight-binding model to…
(abridged) The heating mechanism at high densities during M dwarf flares is poorly understood. Spectra of M dwarf flares in the optical and near-ultraviolet wavelength regimes have revealed three continuum components during the impulsive…
The ultrafast dynamics of surface electromagnetic waves photogenerated on aluminum film perforated with subwavelength holes array was studied in the visible spectral range by the technique of transient photomodulation with 100 fs time…
We present results of a microwave surface impedance study of the heavy fermion superconductor UBe13. We clearly observe an absorption peak whose frequency- and temperature-dependence scales with the BCS gap function. Resonant absorption…
We study the ultrafast dynamics of surface electromagnetic waves photogenerated on aluminum film perforated with subwavelength holes array by means of transient photomodulation with 100 fs time resolution. We observed a pronounced blueshift…
Composite optical systems can show compelling collective dynamics. For instance, the cooperative decay of quantum emitters into a common radiation mode can lead to superradiance, where the emission rate of the ensemble is larger than the…
Energy relaxation in light-harvesting complexes has been extensively studied by various ultrafast spectroscopic techniques, the fastest processes being in the sub-100 fs range. At the same time much slower dynamics have been observed in…