Surface plasmon polariton based optical beam profiler

We demonstrate a novel surface plasmon polariton (SPP) based optical beam profiler with submicroscopic spatial resolution and the potential to be applied directly onto a photodiode. A sharp step of a gold thin film is positioned in the focal region of a light beam, converting light to SPPs. The SPPs emit directed leakage radiation into the glass substrate supporting the thin film. The leakage radiation intensity is proportional to the incident local light intensity at the position of the step, allowing to reconstruct the optical field profile by scanning the thin film edge through the focal region. (author)