Transformation and amplification of light modulated by a traveling wave with a relatively low frequency
M. Sumetsky
The behavior of electromagnetic waves in a medium modulated in time and space, largely investigated decades ago, has recently attracted renewed interest. Here, we address an intriguing problem of this research: can light with an initial frequency ω 0 be amplified solely pumped by a traveling wave with a much lower frequency ω p ≪ ω 0 ? Generally, the bandwidth of the modulation-induced optical frequency comb spectrum can be substantially broadened when the phase velocity of the traveling wave, v p , approaches the phase velocity of light, v 0 . However, in realistic photonic waveguides, the amplification effect remains small due to the unfeasible modulation and waveguide parameters required. In contrast, we demonstrate that modulating an optical resonator by a traveling wave having the frequency ω p and phase velocity v p much smaller than the frequency ω 0 and phase velocity v 0 of light can result in large light amplification accompanied by conversion to multiple comb lines within a relatively small frequency band.
arXiv:2409.12775•Physical Review Research•Sep 26, 2025•3 citations