Role of hot electron scattering in epsilon-near-zero optical nonlinearity
Wang Heng,
Du Kang,
Liu Ruibin,
Dai Xinhai,
Zhang Wending,
Chua Soo Jin,
Mei Ting
Affiliations
Wang Heng
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
Du Kang
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
Liu Ruibin
Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China
Dai Xinhai
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
Zhang Wending
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
Chua Soo Jin
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
Mei Ting
MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
The physical origin of epsilon-near-zero (ENZ) optical nonlinearity lies in the hot-electron dynamics, in which electron scattering plays an important role. With the damping factor defined by hot electron scattering time, the Drude model could be extended to modeling ENZ optical nonlinearity completely. We proposed a statistical electron scattering model that takes into account the effect of electron distribution in a nonparabolic band and conducted the investigation on indium tin oxide (ITO) with femtosecond-pump continuum-probe experiment. We found that ionized impurity scattering and acoustic phonon scattering are the two major scattering mechanisms, of which the latter had been neglected before. They dominate at low-energy and high-energy electrons, respectively, and are weakened or boosted for high electron temperature, respectively. The electron energy–dependent scattering time contributed from multiple scattering mechanisms shows the electron density–dependent damping factor. The comprehensive understanding of electron scattering in ITO will help to develop a complete model of ENZ optical nonlinearity.
