Photocurrent induced by applying of bicircular light

Nonlinear optical responses in solids, including photovoltaic effect and harmonic generation, are physical phenomena triggered by intense light irradiation to materials. These are of great importance in studying the physics of excited states of the system as well as for applications to optical devices and solar cells. In particular, bulk photovoltaic effect (BPVE), namely DC photocurrents in response to uniform AC external fields, have attracted great attention as related to the Berry phase and the band topology of materials [1]. Here we propose the mechanism of a novel photocurrent induced by two-frequency drive with bicircular light (BCL), which can control the rotational symmetry of the system [2]. While ordinary second-order photocurrents can exist only in systems lacking inversion symmetry, BCL driving can induce photocurrents in materials with inversion or rotational symmetry. In particular, since BCL driving also breaks the time-reversal symmetry of the system, the photocurrent proportional to the relaxation time is dominant, called injection current. We show theoretically, using the Feynman diagrammatic method and the Keldysh-Floquet formalism, that BCL irradiation can produce third-order photocurrent and dynamically control the direction of the photocurrent.

[1] T. Morimoto and N. Nagaosa, Sci. Adv. 2, e1501524 (2017)

[2] Y. Ikeda et. al., Prog. Theor. Exp. Phys. ptab127 (2021)