Three-dimensional imaging of direct-written photonic structures

Third-harmonic generation microscopy has been used to analyze the morphology of photonic structures created using the femtosecond laser direct-write technique. Three-dimensional waveguide arrays and waveguide-Bragg gratings written in fused-silica and doped phosphate glass were investigated. A sensorless adaptive-optical system was used to correct the optical aberrations occurring in the sample and microscope system, which had a lateral resolution of less than 500nm. This nondestructive testing method creates volume reconstructions of photonic devices and reveals details invisible to other linear microscopy and index profilometry techniques. (C) 2011 Optical Society of America