Work

Second harmonic generation and nonlinear frequency conversion in photonic time-crystals

Year: 2025

Type: article

Abstract: We study the nonlinear process of second harmonic generation in photonic time-crystals, materials with refractive index that varies abruptly and periodically in time, and obtain the phase matching condition for this process. We find conditions for which the second harmonic generation is highly enhanced even in the absence of phase matching, governed by the exponential growth of the modes residing in the momentum gap of the photonic time crystal. Additionally, under these conditions, a cascade of higher-order harmonics is generated at growing exponential rates. The process is robust, with no requirement for phase-matching, the presence of a resonance or a threshold, drawing energy from the modulation.

Source: Light Science & Applications

DOI: 10.1038/s41377-025-01788-z

Authors: Noa Konforty, Moshe-Ishay Cohen, Ohad Segal, Yonatan Plotnik, Vladimir M. Shalaev, Mordechai Segev

Institutions: Technion – Israel Institute of Technology, United States Department of Energy, Purdue University West Lafayette, Quantum Science Center

Language: English

Topic: Photonic Crystals and Applications

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,190

Funders: Israel Science Foundation, U.S. Air Force, Air Force Office of Scientific Research