Abstract

When graphene is subjected to a strong light field, its nonlinear optical response allows only odd harmonic emissions because of a centrosymmetric structure. We demonstrate that this limitation no longer holds when the generation of an electric current density is considered within a quantum theory because of the involvement of the Rabi oscillation in the nonlinear optical response. By transforming the time-dependent Dirac equation into the length gauge, the Rabi frequency in graphene can be defined, allowing the identification of the Rabi coupling effect on the current-induced harmonic spectra. In particular, a peak at the spectral position of the second harmonic of the incident light can be generated in graphene when the intensity of the incident light causes the Rabi frequency to become comparable with the frequency of the incident light, which was demonstrated in ZnO with a measurement of carrier-envelope-offset frequency [Phys. Rev. Lett. 90, 217404 (2003) [CrossRef]  ]. Moreover, as the light intensity increases, we show that a broadband harmonic spectrum is generated and that a compact electron distribution caused by multiphoton absorptions is produced because of highly nonlinear effects associated with the Rabi oscillation.

© 2014 Optical Society of America

Quantum Rabi oscillations in graphene

Enamullah, Vipin Kumar, Upendra Kumar, and Girish S. Setlur
J. Opt. Soc. Am. B 31(3) 484-493 (2014)

All-optical tunable notch filter by use of Kerr nonlinearity in the graphene microribbon array

Hadiseh Nasari and Mohammad Sadegh Abrishamian
J. Opt. Soc. Am. B 31(7) 1691-1697 (2014)

Band-anisotropy induced Bloch–Siegert shift in graphene

Upendra Kumar, Vipin Kumar, Enamullah, and Girish S. Setlur
J. Opt. Soc. Am. B 31(12) 3042-3049 (2014)

Second-order nonlinear optical response of graphene irradiated by two-color lights: ellipticity and phase modulation

Sen Pei, Suqing Duan, Ning Yang, and Wei Zhang
J. Opt. Soc. Am. B 38(9) 2594-2602 (2021)

Detecting the degree of macroscopic quantumness using an overlap measurement

Hyunseok Jeong, Changsuk Noh, Seunglee Bae, Dimitris G. Angelakis, and Timothy C. Ralph
J. Opt. Soc. Am. B 31(12) 3057-3066 (2014)