Reconfigurable opto-thermal graded-index waveguiding in bulk chalcogenide glasses

In the absence of suitable deposition processes, the fabrication of graded-index chalcogenide waveguides or fibers remains an outstanding challenge. Here, by exploiting the strong thermo-optic effect present in chalcogenide glasses, we experimentally demonstrate non-permanent optically-induced waveguides in bulk As₂Se₃ rods using a 1.55 μm wavelength laser. This single-step process can be used not only to self-trap the writing beam, but also to guide another optical beam at a different wavelength in the opto-thermally inscribed waveguide channel. These results could pave the way towards harnessing nonlinear effects in graded-index chalcogenide guided settings.