title: Intensity-dependent modulation of optically active signals in a chiral metamaterial.
abstract: Chiral media exhibit optical phenomena that provide distinctive responses from opposite circular polarizations. The disparity between these responses can be optimized by structurally engineering absorptive materials into chiral nanopatterns to form metamaterials that provide gigantic chiroptical resonances. To fully leverage the innate duality of chiral metamaterials for future optical technologies, it is essential to make such chiroptical responses tunable via external means. Here we report an optical metamaterial with tailored chiroptical effects in the nonlinear regime, which exhibits a pronounced shift in its circular dichroism spectrum under a modest level of excitation power. Strong nonlinear optical rotation is observed at key spectral locations, with an intensity-induced change of 14° in the polarization rotation from a metamaterial thickness of less than λ/7. The modulation of chiroptical responses by manipulation of input powers incident on chiral metamaterials offers potential for active optics such as all-optical switching and light modulation.
authors.affiliation: School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.|School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Rodrigues
authors.affiliation: School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Shoufeng
authors.initials: S
authors.lastname: Lan
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Kang
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Yonghao
authors.initials: Y
authors.lastname: Cui
authors.affiliation: School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Panuski
authors.affiliation: School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.|School of Electronic and Electrical Engineering, Wuhan Textile University, Wuhan 430073, China.
authors.forename: Shengxiang
authors.initials: S
authors.lastname: Wang
authors.affiliation: Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433, USA.
authors.forename: Augustine M
authors.initials: AM
authors.lastname: Urbas
authors.affiliation: School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.|School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Wenshan
authors.initials: W
authors.lastname: Cai