title: Phase conjugation and negative refraction using nonlinear active metamaterials.
abstract: We present an experimental demonstration of phase conjugation using nonlinear metamaterial elements. Active split-ring resonators loaded with varactor diodes are demonstrated theoretically to act as phase-conjugating or time-reversing discrete elements when parametrically pumped and illuminated with appropriate frequencies. The metamaterial elements were fabricated and shown experimentally to produce a time-reversed signal. Measurements confirm that a discrete array of phase-conjugating elements act as a negatively refracting time-reversal rf lens only 0.12λ thick.
authors.affiliation: Department of Electrical and Computer Engineering and Center for Metamaterials and Integrated Plasmonics, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Katko
authors.forename: Shi
authors.initials: S
authors.lastname: Gu
authors.forename: John P
authors.initials: JP
authors.lastname: Barrett
authors.forename: Bogdan-Ioan
authors.initials: BI
authors.lastname: Popa
authors.forename: Gennady
authors.initials: G
authors.lastname: Shvets
authors.forename: Steven A
authors.initials: SA
authors.lastname: Cummer