Related papers: Sub-Cycle Optical Response Caused by Dressed State…
We investigate the absorption line shapes of laser-dressed atoms beyond the single-atom response, by using extreme ultraviolet (XUV) attosecond pulse trains to probe an optically thick helium target under the influence of a strong infrared…
Recently discovered reactive optical forces have nule time-average of their instantaneous values on monochromatic illumination, so that their detection suggests the use of ultrafast optics, specially in the femto and attosecond domains. By…
We theoretically show that core-excited state populations can be efficiently manipulated with strong optical fields during their decay, which takes place in a few femtoseconds. We focus on the $1s^{-1}3p$ resonant excitation in neon, where…
Strong-field phenomena driven by an intense infrared (IR) laser depend on during what part of the field cycle they are initiated. By changing the sub-cycle character of the laser electric field it is possible to control such phenomena. For…
To coherently control a few-level quantum emitter, typically pulses with an energy resonant to the transition energy are applied making use of the Rabi mechanism, while a single off-resonant pulse does not result in a population inversion.…
Attosecond spectroscopy comprises several techniques to probe matter through electrons and photons. One frontier of attosecond methods is to reveal complex phenomena arising from quantum-mechanical correlations in the matter system, in the…
We investigate laser-driven electron dynamics in solids on the atomic scale and in real space within Floquet formalism, and develop a method based on subcycle-resolved x-ray-optical wave mixing to reconstruct those dynamics. We analyze how…
Nonequilibrium hidden states, both transient and long-lived, provide a unique window into thermally inaccessible regimes of strong coupling between microscopic degrees of freedom in quantum materials. Understanding the physical origin of…
We report results from ultrafast two-color optical pump-probe spectroscopy on bulk $\beta$-Ga$_2$O$_3$. A two-photon absorption scheme is used to photoexcite carriers with the pump pulse and free-carrier absorption of the probe pulse is…
Quantum dots in GaAs/InGaAs structures have been proposed as a candidate system for realizing quantum computing. The short coherence time of the electronic quantum state that arises from coupling to the nuclei of the substrate is…
When two-photon interactions are induced by down-converted light with a bandwidth that exceeds the pump bandwidth, they can obtain a behavior that is pulse-like temporally, yet spectrally narrow. At low photon fluxes this behavior reflects…
Motivated by recent interests in exploring excitonic condensate as the ground state of some narrow-bandgap semiconductors such as transition metal dichalcogenides and layered chalcogenide material Ta$_2$NiSe$_5$, in this work we…
Recently, the switching between the different charge-ordered phases of 1T-TaS2 has been probed by ultrafast techniques, revealing unexpected phenomena such as "hidden" metastable states and peculiar photoexcited charge patterns. Here, we…
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,…
We demonstrate a two-dimensional time-domain spectroscopy method to extract amplitude and phase modifications of excited atomic states caused by the interaction with ultrashort laser pulses. The technique is based on Fourier analysis of the…
We examine electromagnetically induced transparency (EIT) in an ensemble of cold $\Lambda-$type atoms induced by a quantum control field in multi-mode coherent states and compare it with the transparency created by the classical light of…
We give an overview of our recent theoretical studies of the thermodynamics of excitons, and other solid-state qubits, driven by time-dependent laser fields. We consider a single such emitter and describe how the formation of strong-field…
Dressed spin states, a spin coupling to continuous radiation fields, can fundamentally change how a spin responds to magnetic fluctuations. Using dressed spin states, we were able to protect an electron spin in diamond from decoherence.…
Highly asymmetric optical properties of b-Ga2O3 are investigated by polarization-dependent photoluminescence (PL) excitation spectroscopy for assessing its potential use for a novel ultraviolet emitter and nonlinear optical material. Based…
We have studied the absorption of a weak probe beam through cold rubidium atoms in a magneto-optic trap. The absorption spectrum shows two peaks with the smaller peak having linewidth as small as 28% of the natural linewidth. The…