Self-isolated nanoscale laser

Researchers in the Dionne group at Stanford have designed a nanoscale laser capable of self-isolated Raman Lasing, where lasing and isolation occurs within the same pumping mechanism. Coherent light sources must be isolated from potentially damaging back reflections and signal degradation, but typical optical isolation adds significant bulk, making small-scale, densely integrated photonics networks infeasible. Stanford researchers have solved this issue by integrating an optically isolating metasurface (figure 1) that acts as a one-way valve for light into the light source - trapping light to enhance Raman amplification and controlling scattering. The cylindrical geometry manipulates electric and magnetic dipole moments separately, while differing symmetry conditions couples and spatially reorients otherwise orthogonal modes.

Since the optical isolation is designed into the light source itself, it's compact, efficient and compatible with mature CMOS fabrication technologies, which makes integrated photonics feasible in delivering the broadband, high-density and high-speed interconnectivity needed for advanced telecommunication networks and high-performance signal processing.

Stage of Development – Prototype
Researchers are working with a ~1500 nm laser prototype designed in silicon for operation at telecom frequencies. The technique can be used with other lasing media, including solid-state materials that provide gain (e.g. InGaAs, GaAs, GaN, and AlN), rare-earth doped materials, and polymeric gain materials.