Abstract
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 ω0 be amplified solely pumped by a traveling wave with a much lower frequency ωp≪ω0? Generally, the bandwidth of the modulation-induced optical frequency comb spectrum can be substantially broadened when the phase velocity of the traveling wave, vp, approaches the phase velocity of light, v0. 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 ωp and phase velocity vp much smaller than the frequency ω0 and phase velocity v0 of light can result in large light amplification accompanied by conversion to multiple comb lines within a relatively small frequency band.
| Original language | English |
|---|---|
| Article number | 043066 |
| Number of pages | 23 |
| Journal | Physical Review Research |
| Volume | 7 |
| Issue number | 4 |
| Early online date | 17 Oct 2025 |
| DOIs | |
| Publication status | E-pub ahead of print - 17 Oct 2025 |
Bibliographical note
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOIData Access Statement
The data that support the findings of this article are not publicly available. The data are available from the authors upon reasonable request.Funding
This research was supported by the Engineering and Phys- ical Sciences Research Council (Grants No. EP/W002868/1 and No. EP/X03772X/1), Leverhulme Trust (Grant No. RPG- 2022-014), and Royal Society (Grant No. IES\ R1\ 231250).