Ultrafast laser writing quill effect in low loss waveguide fabrication regime

Quill effect, one of the intriguing phenomena in ultrafast laser writing, to our knowledge, has not been studied in low-loss-waveguide (LLW) writing regime yet, probably due to its invisibility under conventional white-light microscope in that regime. In this report, with help of adaptive third harmonic generation microscopy we reveal the quill effect in LLW writing regime and study its influences on the properties of written photonic integrated components in term of polarization-related properties in fused silica and beam-splitting ratio of three-waveguide-coupler in borosilicate glass.