Polychromatic digital optics for structured light

Descrizione del progetto

Un modulatore di luce spaziale a elevata efficienza nello spettro visibile

I modulatori di luce spaziale costituiscono una classe di dispositivi ottici che applicano una sorta di modulazione spazialmente variabile a un fascio luminoso. I dispositivi all’avanguardia funzionano in maniera efficiente unicamente in presenza di una determinata lunghezza d’onda. Il progetto BB-SLM, finanziato dal programma Marie Skłodowska-Curie, intende creare un modulatore di luce spaziale controllato digitalmente che darà prova di elevata efficienza nell’intero spettro visibile. Per raggiungere questo obiettivo, il progetto combinerà uno sfasatore geometrico acromatico con la riflessione circolare di Bragg proveniente da cristalli liquidi chirali spazialmente modulati. Le strutture topologiche intrinsecamente solide che emergeranno spontaneamente nei sistemi di materia soffice, quali i cristalli liquidi, permetteranno di controllare l’interazione tra lo stato di polarizzazione della luce e i suoi gradi di libertà spaziale.

Obiettivo

The development of photonics technologies implies ever-increasing agile optical components operating enabling the manipulation of the spatial degrees of freedom of light over broad spectral ranges. To date, spatial light modulators is a class of digital optical devices offering versatile management of light, however, state-of-the-art devices are operating efficiently only at a given wavelength. Here we propose to develop a digitally controlled spatial light modulator combining efficiency with intrinsically broadband behavior spanning the whole visible spectrum. This will be accomplished by integrating the advantage of spin controlled achromatic geometric Berry phase with broadband polarization-dependent circular Bragg reflection from spatially modulated chiral liquid crystals. Despite more than a century-long history of liquid crystals, the first report on the accumulation of Berry phase due to Bragg reflection came only very recently from the research group lead by the host scientist. The proposed two-year project to develop spatial light-modulators based on this basic physical principle. By doing so, we aim at controlling the interaction between the polarization state of light with its spatial degrees of freedoms (i.e. the spin-orbit interaction of light) by exploiting the inherently robust and diverse topological structures that spontaneously appear in anisotropic soft condensed matter systems such as liquid crystals. In particular, we will take advantage of both the self-organization orientational processes occurring in liquid crystals and their extreme sensitivity to external fields. By implementing a recently demonstrated physical concepts into a novel generation of spin-orbit optical devices enabling spatial control of the optical phase over a broad spectral range, this project will offer further possible applications for advanced photonic technologies, for instance in optical data processing, optical imaging and optical manipulation.