High-harmonic generation in graphene enhanced by elliptically polarized light excitation

• Autores: Naotaka Yoshikawa, Tomohiro Tamaya, Koichiro Tanaka
• Localización: Science, ISSN 0036-8075, Vol. 356, Nº 6339, 2017, págs. 736-738
• Idioma: inglés
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• Resumen

  • The electronic properties of graphene can give rise to a range of nonlinear optical responses. One of the most desirable nonlinear optical processes is high-harmonic generation (HHG) originating from coherent electron motion induced by an intense light field. Here, we report on the observation of up to ninth-order harmonics in graphene excited by mid-infrared laser pulses at room temperature. The HHG in graphene is enhanced by an elliptically polarized laser excitation, and the resultant harmonic radiation has a particular polarization. The observed ellipticity dependence is reproduced by a fully quantum mechanical treatment of HHG in solids. The zero-gap nature causes the unique properties of HHG in graphene, and our findings open up the possibility of investigating strong-field and ultrafast dynamics and nonlinear behavior of massless Dirac fermions.