Toroidal lasing spaser

• Main Authors: Huang, Yao-Wei, Chen, Wei Ting, Wu, Pin Chieh, Fedotov, Vassili A., Zheludev, Nikolay I., Tsai, Din Ping
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2013
• Subjects: DRNTU::Science::Physics::Radiation physics
• Online Access: https://hdl.handle.net/10356/97306; http://hdl.handle.net/10220/9999
• Institution: Nanyang Technological University

Toroidal shapes are often found in bio-molecules, viruses, proteins and fats, but only recently it was proved experimentally that toroidal structures can support exotic high-frequency electromagnetic excitations that are neither electric or magnetic multipoles. Such excitations, known as toroidal moments, could be playing an important role in enhancing inter-molecular interaction and energy transfer due to its higher electromagnetic energy confinement and weaker coupling to free space. Using a model toroidal metamaterial system, we show that coupling optical gain medium with high Q-factor toroidal resonance mode can enhance the single pass amplification to up to 65 dB. This offers an opportunity of creating the “toroidal” lasing spaser, a source of coherent optical radiation that is fueled by toroidal plasmonic oscillations in the nanostructure.