Time-refraction optics with single cycle modulation

Eran Lustig, Ohad Segal, Soham Saha, Eliyahu Bordo, Sarah N. Chowdhury, Yonatan Sharabi, Avner Fleischer, Alexandra Boltasseva, Oren Cohen, Vladimir M. Shalaev, Mordechai Segev*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We present an experimental study of optical time-refraction caused by time-interfaces as short as a single optical cycle. Specifically, we study the propagation of a probe pulse through a sample undergoing a large refractive index change induced by an intense modulator pulse. In these systems, increasing the refractive index abruptly leads to time-refraction where the spectrum of all the waves propagating in the medium is red-shifted, and subsequently blue-shifted when the refractive index relaxes back to its original value. We observe these phenomena in the single-cycle regime. Moreover, by shortening the temporal width of the modulator to ∼5-6 fs, we observe that the rise time of the red-shift associated with time-refraction is proportionally shorter. The experiments are carried out in transparent conducting oxides acting as epsilon-near-zero materials. These observations raise multiple questions on the fundamental physics occurring within such ultrashort time frames, and open the way for experimenting with photonic time-crystals, generated by periodic ultrafast changes to the refractive index, in the near future.

Original languageEnglish
Pages (from-to)2221-2230
Number of pages10
Issue number12
StatePublished - 1 Jun 2023


FundersFunder number
U.S. Department of Energy
Air Force Office of Scientific ResearchFA9550-21-1-0299, 2032635
Air Force Office of Scientific Research
Basic Energy Sciences
Division of Materials Sciences and EngineeringDE-SC0017717
Division of Materials Sciences and Engineering


    • Photonic time-crystals
    • time-varying media
    • ultrafast optics


    Dive into the research topics of 'Time-refraction optics with single cycle modulation'. Together they form a unique fingerprint.

    Cite this