Giving light a new twist with standard optical fibres: rainbow Archimedean spiral emission

TL;DR

This paper introduces a practical method to generate multicolour spiral-shaped beams using standard silica optical fibres and a tilted laser beam, enabling rainbow emission independent of laser wavelength or polarization.

Contribution

It demonstrates a novel approach for producing multicolour spiral beams with standard optical fibres, expanding potential applications in communications, optical tweezers, and quantum optics.

Findings

Generation of spiral-shaped beams using standard fibres and tilted input beams.

Rainbow multicolour emission independent of laser wavelength and polarization.

Stable spiral emission observed with high-power femtosecond lasers.

Abstract

We demonstrate a new practical approach for generating multicolour spiral-shaped beams. It makes use of a standard silica optical fibre, combined with a titled input laser beam. The resulting breaking of the fibre axial symmetry leads to the propagation of a helical beam. The associated output far-field has spiral shape, independently of the input laser power value. Whereas, with a high-power near-infrared femtosecond laser, a visible supercontinuum spiral emission is generated. With appropriate control of the input laser coupling conditions, the colours of the spiral spatially self-organize in a rainbow distribution. Our method is independent of the laser source wavelength and polarization. Therefore, standard optical fibres may be used for generating spiral beams in many applications, ranging from communications to optical tweezers and quantum optics.