Probing the dephasing time of crystals via spectral properties of high-order harmonic generation

Abstract

Coherent time is a characteristic time in the extreme nonlinear optics regime and thus generally introduced as the dephasing time in the simulations of the solid-state high-harmonic generation. This characteristic time linked with the coherent decay of quantum trajectory controls the emergence of the spectral splittings in the high harmonic spectroscopy, which can been attributed to the temporal interference between two adjacent harmonic emission channels. To reproduce the harmonic peaks and spectral splittings, a temporal two-slit interference model in the momentum space is introduced. In addition, mechanisms of spectral splitting provide a state-of-the-art avenue to probe the characteristic elapse between electron and hole. Based on the subfemtosecond resolution of the spectral interference opening and closing zones in the wavelength-dependent high-order harmonic spectra, we also propose an alternative scheme to probe the dephasing time of crystals by the feasible laser pulses in present experimental setups.

Dephasing Dynamics Accessed by High Harmonic Generation: Determination of Electron–Hole Decoherence of Dirac Fermions

“…While the interplays between distinct transition channels provide unique harmonic sources, the decoherence now can interfere with the release of HHG depending on the scattering nature. − The decoherence time T 2 , i.e., the dephasing time for loss of electron–hole coherence due to the coupling with nonequilibrium dissipation, is of utmost importance for the physics of coherent quantum control, for instance, like quantum information and computing. , In contrast to the population decay T 1 , the measurement of T 2 usually requires highly nontrivial methods, including the four-wave mixing and pump–probe technique, which just remain in the limited and relative time scale. Beyond the pump–probe scheme, it would be timely to suggest an exquisite pathway for an estimation of T 2 on the basis of quantified evidence for the scattering nature, resulting in the dissipation and the relevant dynamic links among underlying physics.…”

Supplementary document for Observing quantum-path interference and Van Hove singularity in polarization-resolved high-harmonic spectroscopy - 5156756.pdf

“…To study polarization dependence of HHG in w-ZnO, one valence band (V) and two conduction bands (C1 and C2) are adopted in the numerical simulations. The 3D energy band is denoted as [1,2,4,5]. To guarantee the crystal symmetry and size of the BZ, an analytical form of the energy bands is given by E m,xy (k x , k y ) = (t m f + q m + t m f + p m )/27.2 and E m,z (k z ) = ∑ 1 j=0 α z m,j cos(jk z a z ), where f = 2 cos( √ 3k y a y ) + 4 cos(…”

Toy model of harmonic and sum frequency generation in 2D dielectric nanostructures

“…Such engineering depends on understanding the dependence of nonlinear optical properties on the arrangement of atoms. Full ab-initio quantum treatments of second- 23 – 29 and higher-order 30 , 31 nonlinearity have been demonstrated, but only for specific materials and under specific conditions, whilst experimental measurements, of surface nonlinearity, require pristine surfaces and strict control over the bulk effects 3 , 5 , 32 – 34 . Sophisticated classical/quantum test models have been previously developed for metals 35 , 36 , ‘dipolium’ dielectrics 29 , 37 , and dielectric particles of quite specific shapes 38 .…”