Acousto-optical nanoscopy of buried photonic nanostructures

Abstract

We develop a nanoscopy method with in-depth resolution for layered photonic devices. Photonics often require tailored light field distributions for the operated optical modes and an exact knowledge of the geometry of a device is crucial to assess its performance. We present an acousto-optical nanoscopy method for the characterization of layered photonic structures based on the uniqueness of the light field distributions: for a given wavelength, we record the reflectivity modulation during the transit of a picosecond acoustic pulse. The obtained temporal profile can be linked to the internal light field distribution. From this information, a reverse-engineering procedure allows us to reconstruct the light field and the underlying photonic structure very precisely. We apply this method to the slow light mode of an AlAs/GaAs micropillar resonator and show its validity for the tailored experimental conditions.