Development of silicon nitride phase shifted Bragg grating cantilever for AFM-IR

Abstract

To investigate nanoscale dynamics in materials, atomic force microscopy infrared spectroscopy (AFM-IR) systems require fast and small cantilevers. The current interferometric readout method introduces excessive noise when the dimensions of the cantilever is smaller than the laser beam spot size. To address this challenge, we propose a novel cantilever design with an embedded phase-shifted Bragg grating (PSBG). Optimized using Lumerical, the PSBG is designed to operate near 1550 nm. Experimental characterization of the PSBGs on both the cantilevers under self-deflection and the bulk substrate revealed a wavelength red shift of approximately 3 nm.