New publication in Phys. Rev. Lett.: Polarization-Tailored Raman Frequency Conversion in Chiral Gas-Filled Hollow-Core Photonic Crystal Fibers
As a novel platform for chiral nonlinear interactions, twisted hollow-core photonic crystal fibre filled with gas opens up new perspectives for broadband light sources with controllable polarisation state. The circular birefringence of these chiral fibres permits the robust preservation of the spin of light against external perturbations over unprecedentedly long distances. This property, along with a high damage threshold and broad transmission window, makes it possible to generate pure circularly-polarised Stokes and anti-Stokes signals by rotational Raman scattering in hydrogen. The polarisation state of the frequency-shifted Raman bands can be continuously varied by tuning the gas pressure in the vicinity of the gain-suppression point, as shown in the figure. These results pave the way towards new compact fibre-based approaches for generation, control and delivery of broadband circularly polarised light.