Few-cycle fiber pulse compression and evolution of negative resonant radiation

Abstract

We present experimental observations of the spectral expansion of fs-pulses compressing in optical fibers. Using the input pulse frequency chirp we are able to scan through the pulse compression spectra and observe in detail the emergence of negative-frequency resonant radiation (NRR), a recently discovered pulse instability coupling to negative frequencies. We observe how the compressing pulse is exciting NRR as long as it overlaps spectrally with the resonant frequency. Furthermore, we observe that optimal pulse compression can be achieved at an optimal input chirp and for an optimal fiber length. Our measurements are supported by simulations of the compressing pulse propagation. The results are important for Kerr-effect pulse compressors, to generate novel light sources, as well as for the observation of quantum vacuum radiation.

The next generation of analogue gravity experiments

“…An important ingredient of the Hawking effect is the generation of negative frequency waves, such as those observed in the open-channel flow experiments [15]. A series of experiments between 2012 and 2018 demonstrated the generation of negative frequency waves in optical fibres and bulk systems [17][18][19].…”

Analytical description of quantum emission in optical analogs to gravity

“…When the group velocity of the RIF matches the group velocity of waves in the visible, the Hawking effect may create pairs of photons in the UV (the partner) and visible (HR). This can be achieved by using a similar medium to ours, for example metamaterial waveguides, such as photonic crystal fibres [32,[35][36][37]46]. In the anomalous dispersion region, a soliton can be generated in the fibre [44].…”

Quasi-Phase-Matched Supercontinuum Generation in Photonic Waveguides

“…Specifically, when phase-matching between a soliton and quasi-continuous-wave (CW) light is achieved, strong enhancements of the intensity of the supercontinuum spectrum can occur in certain spectral regions. These spectral peaks are often referred to as a dispersive waves (DWs) [2,[20][21][22], and they are often crucial for providing sufficient spectral brightness for many applications. The soliton-DW phase-matching condition is typically satisfied by selecting a material with a favorable refractive index profile and engineering the dimensions of the waveguide to provide DWs at the desired wavelengths [15,16].…”