Photonic lantern imaging

Abstract

The photonic lantern is an adiabatic transition from an array of single-­mode waveguides to a single multimode waveguide, which has found use historically in astrophotonics as a reformatter of light from multimode to single mode, facilitating advanced instrumentation, and in communication networks to allow better coupling and spatial multiplexing. The device has never before been used for imaging, but is suited to certain forms of compressive sensing. Light is coupled into each of the single­mode waveguides at the input to a multicore fibre photonic lantern, producing intensity patterns at the output of that lantern which are stable to bending, and which are used as the sampling basis for a variant of compressive imaging related closely to ghost imaging. Improvements to such imaging modalities require a greater number of modes to be excited simultaneously, requiring a lantern with stable polarisation properties. With the aid of a de novo fabricated integrated lantern custom­-manufactured for such tuned properties, more advanced techniques are explored. These include coherent combination of mode patterns to increase the possible sampling basis, as well as more complex techniques of beamshaping at the lantern output facet through holographic projection. These proofs-­of-­concept of the novel imaging techniques show the previously undiscovered value of photonic lanterns in the field of imaging, and their promise for endomicroscopy systems.