Control of High-Harmonic Generation by Tuning the Electronic Structure and Carrier Injection

Abstract

High-harmonic generation (HHG), which is generation of multiple optical\nharmonic light, is an unconventional nonlinear optical phenomenon beyond\nperturbation regime. HHG, which was initially observed in gaseous media, has\nrecently been demonstrated in solid state materials. How to control the extreme\nnonlinear optical phenomena is a challenging subject. Compared to atomic gases,\nsolid state materials have advantages in controlling electronic structures and\ncarrier injection. Here, we demonstrate control of HHG by tuning electronic\nstructure and carrier injection using single-walled carbon nanotubes (SWCNTs).\nWe reveal systematic changes in the high-harmonic spectra of SWCNTs with a\nseries of electronic structures from a metal to a semiconductor. We demonstrate\nenhancement or reduction of harmonic generation by more than one order of\nmagnitude by tuning electron and hole injection into the semiconductor SWCNTs\nthrough electrolyte gating. These results open a way to control HHG within the\nconcept of field effect transistor devices.\n