Physicist – Experimentalist

Deadline : 30th of November

-       Dual-comb spectroscopy:

-        Multimode nonlinear optics:

-        Nonlinear fiber optics:

-        Dispersive shock waves:

ANR OptiRoC: Optical Rogue Waves in Nonlinear Cavities

https://sites.google.com/site/optirocproject/home

me

The project aims to address the extended problems of rogue waves in realistic dissipative optical systems, 
because all physical and natural systems are dissipative in reality.

Two specific purposes: 
- to develop optical workbenches based on nonlinear cavity systems with controllable complexity that can be varied in precisely chosen ways,
- to develop both theoretical understanding and experimental demonstration of the regimes for which very intense localized structures exhibiting rogue event signatures can be generated and controlled.

Dual-comb spectroscopy

The project is developped in collaboration with Nathalie Picqué, Yan Ming and Theodor Hänsch at MPQ in Garching.

We have recently proposed an original technique of spectroscopy, which opens up novel opportunities for sensitive, ultra-rapid and precise molecular sensing. This technique results from advanced concepts and tools of optical communications which are harnessed to support new insights on frequency comb generation. It consists in generating two mutually-coherent and frequency-agile combs from a single CW tunable laser, giving them very good mutual coherence, thus avoiding any need of synchronization [G. Millot et al., Nat. Photon. 10, 27 (2016)]. The CW laser is intensity modulated by two optics modulators driven by electrical pulse generators set at slightly different frequencies . Combs consist of 50-ps pulses To ensure operation of the spectrometer over a spectral range of several nanometers, the two combs are spectrally-broadened by DSWs [A. Parriaux et al., Opt. Lett. 42, 3044 (2017)]in a normally dispersive optical fiber. Importantly, for efficient common-noise rejection and for maintaining the mutual coherence between the two combs, a single fiber was used, in which the two pulse trains counter-propagate and are separated with a circulator at each fiber end. The use of two independent fibers would not allow resolving individual comb lines. The two beams are then combined and their interference leads to a comb in the radio frequency region, thus formed by down-conversion of optical frequencies. The line spacing of the two combs, which gives the spectral resolution, only depends on electronic settings and does not encompass resonant optical elements. Our all-fiber and compact dual-comb spectrometer was developed at the Telecom wavelengths tunable from 1.53 to 1.61 µm with unprecedented refresh rates (100 kHz), tuning speed (10 nm/s), high signal-to-noise ratio (~2000) and moderate spans (~0.5 THz).