Effiencient epsilon-near-zero intracavity dual-range frequency shift
© 2024 PHOSL
The Photonics Systems Laboratory at EPFL worked with collaborators to develop an active photonic system enabled by an epsilon-near-zero intracavity element, demonstrating efficient frequency switching under low light intensity, which is an important step towards implementing epsilon-near-zero frequency shifts on-chip
The Photonic Systems Laboratory (PHOSL) at EPFL collaborated with colleagues from Tsinghua University and Peking University in China to demonstrate for the first time, the realization of dual-range frequency switching via an active optical system with a single intracavity epsilon-near-zero (ENZ) Fabry-Pérot nanostructure.
Highlights
Based on the initial cavity status, the system can induce a long- or short-range mode-locked frequency shift, which is not achievable in the cavity's continuously tunable range. Moreover, the time-stretched discrete Fourier transform technique is employed to investigate the real-time dynamics of the ENZ intracavity frequency switching operation for the first time, proving that the phenomena originate from intracavity mode-selectivity alteration instead of time refraction. Finally, the possibilities of mode-locked frequency encoding, enabling the optical system to perform eight different logic functions are discussed, including four complex non-commutative 2-operand logics.
Importance
ENZ nanophotonic devices with zero permittivity are known to exhibit adiabatic frequency translation via temporal refraction under extracavity excitation by intense light sources, which are however hard to integrate on-chip owing to a high demand for energy density. As this class of complementary-metal-oxide-semiconductor-compatible (CMOS) materials is progressing toward on-chip photonic integration, a more versatile solution with less intensity requirements needs to be further explored.
The results of this work deepen the understanding of ENZ photonics, and extend the applications of ENZ photonics outside the extracavity scenarios. Considering its compatibility with the cutting-edge photonic integration and nanophotonic platforms, the proposed photonic system can be useful in novel and programmable multipurpose photonic logic computing, ultrafast optical signal processing, and versatile optical communications.
Doctoral assistants Jiaye Wu, Gang Wang, Ji Zhou, former PHOSL scientist Dr. Marco Clementi (currently assistant professor at the University of Pravia), Prof. Camille-Sophie Brès at EPFL; PhD candidate Chenxingyu Huang, Dr. Xuanyi Liu, Prof. Hongyan Fu from Tsinghua University and Prof. Qian Li from Peking University contributed to this research.
This work is published in ACS Photonics on 5th December, 2024 and presented in the IEEE Photonics Conference (IPC) on 11th November, 2024 in Rome, Italy.
