Few-cycle lightwave-driven currents in a semiconductor at high repetition rate

Langer, Fabian; Liu, Yen Po; Ren, Zhe; Flodgren, Vidar; Guo, Chen; Vogelsang, Jan; Mikaelsson, Sara; Sytcevich, Ivan; Ahrens, Jan; L’Huillier, Anne; Arnold, Cord L.; Mikkelsen, Anders

doi:10.1364/optica.389150

Cited by 21 publications

(13 citation statements)

References 33 publications

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“…Here the photon energies are resonant with 2 nd -and 3 rdorder perturbative transitions that interfere, and the inversion symmetry is effectively broken by the twocolor field (making the effect highly sensitive to the two-color relative phase). The resonant and perturbative nature of these effects precludes access to ultrafast dynamics and possible applications in the Terahertz regime, and is also limited in its conversion efficiency [29].More recently, nonlinear photocurrents were predicted and observed in dielectrics [30][31][32] and graphene [33][34][35][36] driven by intense quasi-monochromatic few-cycle pulses. The mechanism creating these photocurrents relies on the vector potential of the light field to have a nonzero time integral [32], i.e.…”

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confidence: 99%

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Light-Driven Extremely Nonlinear Bulk Photogalvanic Currents

et al. 2021

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We report on the generation of bulk photocurrents in materials driven by non-resonant bi-chromatic fields that are circularly polarized and co-rotating. The non-linear photocurrents have a fully controllable directionality and amplitude without requiring carrier-envelope-phase stabilization or few-cycle pulses, and are generated with photon energies much smaller than the band gap (reducing heating in the photo-conversion process). We demonstrate with ab-initio calculations that the photocurrent generation mechanism is universal and arises in gaped materials (Si, diamond, MgO, hBN), in semi-metals (graphene), and in two-and three-dimensional systems. Photocurrents are shown to rely on sublaser-cycle asymmetries in the nonlinear response that build-up coherently from cycle-to-cycle as the conduction band is populated. Importantly, the photocurrents are always transverse to the major axis of the co-circular lasers regardless of the material's structure and orientation (analogously to a Hall current), which we find originates from a generalized time-reversal symmetry in the driven system. At high laser powers (~10 13 W/cm 2 ) this symmetry can be spontaneously broken by vast electronic excitations, which is accompanied by an onset of carrier-envelope-phase sensitivity and ultrafast many-body effects. Our results are directly applicable for efficient light-driven control of electronics, and for enhancing sub-band-gap bulk photovoltaic effects.Light-driven dynamics in solids with femtosecond and sub-femtosecond resolution have recently attracted considerable attention. Light-matter interactions can result in novel effects that originate from ultrafast dynamics including high harmonic generation (HHG) [1], and the creation of new states of matter [2][3][4][5][6][7][8][9][10]. The ability to control the electron motion in real-space, momentum-space and time, can give rise to unprecedented control over observable properties such as light emission [11][12][13][14][15][16][17][18][19] and magnetic fields [20]. One main avenue of research here is the generation and characterization of light-driven bulk electric currents in the absence of external bias. In materials with broken inversion symmetry, second-order nonlinear effects lead to shift currents through the bulk photovoltaic effect [21,22]. The driving force for carrier separation in the shift current mechanism is the coherent evolution of electron and hole wavefunctions, such that above-bandgap photovoltages can surpass the Shockley-Queisser limit [23]. Photocurrents can also arise in inversion-symmetric materials (where they are standardly forbidden) via mixing of bi-chromatic carrier waves with frequencies ω and 2ω [20,[24][25][26][27][28]. Here the photon energies are resonant with 2 nd -and 3 rdorder perturbative transitions that interfere, and the inversion symmetry is effectively broken by the twocolor field (making the effect highly sensitive to the two-color relative phase). The resonant and perturbative nature of these effects precludes access to ultrafast dyn...

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mentioning

confidence: 99%

“…More recently, nonlinear photocurrents were predicted and observed in dielectrics [30][31][32] and graphene [33][34][35][36] driven by intense quasi-monochromatic few-cycle pulses. The mechanism creating these photocurrents relies on the vector potential of the light field to have a nonzero time integral [32], i.e.…”

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confidence: 99%

Light-Driven Extremely Nonlinear Bulk Photogalvanic Currents

et al. 2021

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“…In Halbleitern, etwa Galliumnitrid, wurde die Strominjektion ebenfalls demonstriert [9,10] -und schließlich von unserer Gruppe in Graphen [11]. Graphen zeichnet sich als einzigartiges Material aus, da es rein zweidimensional und als Halbmetall bereits bei Raumtemperatur elektrisch leitfähig ist (Details siehe Zusatztext "Graphen" zum Download, unter "Zusatzmaterial").…”

Section: Ein Zwei-niveau-system Etwa Ein Halbleiter Mit Valenzband (V...unclassified

Elektronik auf Lichtfrequenzen

Boolakee

Hommelhoff

2023

Physik in unserer Zeit

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“…Intense few-cycle pulses can induce conductivity within a fraction of an optical cycle, enabling the ultrafast manipulation of electric currents. Such currents have been measured in various materials [1][2][3][4][5] and 2D-structures [6]. Using sub-cycle current injection as a temporal gate, in a generalization of the concept of THz photoconductive fieldsampling [7,8], the field-resolved measurement of optical waveforms up to PHz-frequencies has been demonstrated [9].…”

Section: Introductionmentioning

confidence: 99%

The emergence of macroscopic currents in photoconductive sampling of optical fields

Schötz,

Maliakkal,

Blöchl

et al. 2021

Preprint

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Photoconductive field sampling is a key methodology for advancing our understanding of lightmatter interaction and ultrafast optoelectronic applications. For visible light the bandwidth of photoconductive sampling of fields and field-induced dynamics can be extended to the petahertz domain. Despite the growing importance of ultrafast photoconductive measurements, a rigorous model for connecting the microscopic electron dynamics to the macroscopic external signal is lacking. This has caused conflicting interpretations about the origin of macroscopic currents. Here, we present systematic experimental studies on the macroscopic signal formation of ultrafast currents in gases. We developed a theoretical model based on the Ramo-Shockley-theorem that overcomes the previously introduced artificial separation into dipole and current contributions. Extensive numerical particle-in-cell (PIC)-type simulations based on this model permit a quantitative comparison with experimental results and help to identify the roles of electron scattering and Coulomb interactions. The results imply that most of the heuristic models utilized so far will need to be amended. Our approach can aid in the design of more sensitive and more efficient photoconductive devices. We demonstrate for the case of gases that over an order of magnitude increase in signal is achievable, paving the way towards petahertz field measurements with the highest sensitivity.

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Few-cycle lightwave-driven currents in a semiconductor at high repetition rate

Cited by 21 publications

References 33 publications

Light-Driven Extremely Nonlinear Bulk Photogalvanic Currents

Light-Driven Extremely Nonlinear Bulk Photogalvanic Currents

Elektronik auf Lichtfrequenzen

The emergence of macroscopic currents in photoconductive sampling of optical fields

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