Polarization control in optical fibers and applications in optical microscopy and spectroscopy

We demonstrate the construction of an acoustic long period ber grating (LPG) incorporating an index tailored few-mode ber and discuss its implementation for high resolution microscopy and spectroscopy. The LPG is used to selectively excite radially or azimuthally polarized second-higher order modes. Among many others, possible applications are nano-particle characterization and optical near- eld microscopy. The goal is to increase the feasibility and reliability of nondestructive optical evaluation for micro- and nanoscale devices and nanostructured materials.