Electromagnetic wave frequency upconversion in dynamic media*

Frequency upconversion of an electromagnetic wave can occur in ionized plasma with decreasing electric permittivity and in split-ring resonator-structure metamaterials with decreasing magnetic permeability. This talk will present a general theory [1] to describe the evolution of the wave frequency, amplitude, and energy density in media with temporally decreasing refractive index. It is shown that upconversion of the wave frequency partitions the wave energy into both high- and low-frequency modes, and the efficiencies of frequency upconversion are comparable using decreased permittivity and decreased permeability. This method has important applications including generating coherent and chirped ultraviolet and x-ray pulses with independently tunable frequency and bandwidth [2].  

 

[1] K. Qu, Q. Jia, M. R. Edwards, and N. J. Fisch, arXiv:1804.07358 (2018);

[2]M. R. Edwards, K. Qu, Q. Jia, J. M. Mikhailova, and N. J. Fisch, Phys. Plasmas, 5, 053102, (2018).