Optical Time Reversal from Time-Dependent Epsilon-Near-Zero Media

Stefano Vezzoli, Vincenzo Bruno, Clayton DeVault, Thomas Roger, Vladimir M. Shalaev, Alexandra Boltasseva, Marcello Ferrera, Matteo Clerici, Audrius Dubietis, Daniele Faccio

Research output: Contribution to journalArticlepeer-review

109 Citations (Scopus)
93 Downloads (Pure)


Materials with a spatially uniform but temporally varying optical response have applications ranging from magnetic field-free optical isolators to fundamental studies of quantum field theories. However, these effects typically become relevant only for time variations oscillating at optical frequencies, thus presenting a significant hurdle that severely limits the realization of such conditions. Here we present a thin-film material with a permittivity that pulsates (uniformly in space) at optical frequencies and realizes a time-reversing medium of the form originally proposed by Pendry [Science 322, 71 (2008)SCIEAS0036-807510.1126/science.1162087]. We use an optically pumped, 500 nm thick film of epsilon-near-zero (ENZ) material based on Al-doped zinc oxide. An incident probe beam is both negatively refracted and time reversed through a reflected phase-conjugated beam. As a result of the high nonlinearity and the refractive index that is close to zero, the ENZ film leads to time reversed beams (simultaneous negative refraction and phase conjugation) with near-unit efficiency and greater-than-unit internal conversion efficiency. The ENZ platform therefore presents the time-reversal features required, e.g., for efficient subwavelength imaging, all-optical isolators and fundamental quantum field theory studies.
Original languageEnglish
Article number043902
JournalPhysical Review Letters
Issue number4
Publication statusPublished - 26 Jan 2018


Dive into the research topics of 'Optical Time Reversal from Time-Dependent Epsilon-Near-Zero Media'. Together they form a unique fingerprint.

Cite this