Ultrafast heterodyne mode imaging and refractive index mapping of a femtosecond laser written multimode waveguide
Abstract
We demonstrate imaging of individual modes in a femtosecond laser written multimode waveguide by spatial-heterodyne interferometry and decomposition in data post-processing. Despite the spatial and temporal overlap between multiple waveguide modes, we show the extraction of amplitude for each individual mode and their corresponding temporal dynamics. The mode imaging scheme is effective with the presence of intermodal interference and can be prospective for sensing of ultrafast phase and refractive index fluctuations. We also reconstruct the two-dimensional transverse refractive index map of the multimode waveguide leveraging all the imaged modes and substantiate the reconstructed index map by simulation.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 24, 2021
- Source ID
- 10.1364/ol.444582
Entities
People
- Liang Feng
- Shuang Wu
- Tianwei Wu
- Zhifeng Zhang
- Zihe Gao
Organizations
- Army Research Office
- National Science Foundation
- University of Pennsylvania