Dynamical Fano resonance of an exciton in laser-driven semiconductor superlattices

Abstract

An excitonic Floquet state in semiconductor superlattices (SLs) driven by an intense monochromatic laser is examined based on multichannel scattering theory, where this state is supported by a photon sideband attributed to a SL joint miniband. It is shown that the excitonic Fano resonance (FR) is caused by the coupling between photon sidebands, and thus one obtains the possibility of dynamic quantum control of this exciton state by means of laser tuning. This FR differs from the conventional FR observed in the original SLs without laser irradiation in that the latter FR results from the static Coulomb coupling between different SL joint minibands. Both the q parameter and the spectral width associated with the excitonic FR of concern vary notably with a change of laser strength. In particular, it is found that the FR is made stable, that is, 1/|q| and become minimized, when the laser strength is appropriately tuned to the condition of what is called dynamic localization.

Tunable dynamic Fano resonances in coupled-resonator optical waveguides

“…CROWs have been explored in a variety of material platforms and resonator types, including photonic-crystal defect cavities, microspheres, microdisks, and microring resonators [22,23], with applications to light slowing down and storage [24][25][26], light capturing [27], time reversal [28,29], sensing [30], and for the realization of topologically-protected edge states. [31] While in static CROW structures Fano resonances are usually realized by side-coupled microcavities [2,32], in our setup they arise dynamically from the interference of different Floquet channels [33][34][35][36][37][38], and can be thus controlled by tuning the frequency and amplitude of the modulation signal.…”

Quasienergy resonance in a dynamic Wannier-Stark ladder

“…Although a number of studies of the DWSL have been focused on its importance [49][50][51][52][53] these studies are limited to a small α region, and thus the significance of the ac-ZT interaction is overlooked to the best of our knowledge. Recently, two of the authors have demonstrated the manifestation of an asymmetric Fano lineshape of a photodressed-exciton state in interband absorption spectra, 40,41 though this study just addresses the few-body problem. Further study is in progress, taking account of the many-body effect within the mean-field approximation based on the semiconductor-Bloch equations.…”

“…Further, this has been applied to the study of a more complicated excitonic Floquet problem of the DWSL. 40,41 The present study is regarded as the further developed study of Ref. 19 toward a comprehensive understanding of the DWSL with η integer.…”

Laser-Induced Fano Resonance in Condensed Matter Physics

“…The first category is regarding whether a process is a linear one or a nonlinear one with respect to an order of a laser-matter interaction, as categorized as (a1) and (a2), respectively. For instance, the former is a photoabsorption process [8][9][10][11], and the latter is a multiphoton process [12][13][14][15][16]. The second category is regarding whether the process results from a built-in interaction between the discrete level and continuum that is intrinsic to a material itself or from a coupling induced extrinsically by a laser, as categorized as (b1) and (b2), respectively.…”

“…In other words, this is whether (quasi)time-independent or timedependent. For instance, the former is induced by a continuous-wave (cw) laser (monochromatic laser) [15,16,25,26], and the latter is by a short pulsed laser [27][28][29][30][31].…”