AFM and Nonlinear Optics Combine to Improve Optical Defect Detection

A technique for detecting nanosize imperfections in optical materials could lead to improvements in detector technologies for applications ranging from cellphones to solar cells. The technique developed by a McGill University research team uses atomic force microscopy (AFM) to better understand and control imperfections in optical materials. These nanosize optical defects are difficult to identify and characterize. The McGill team combined nonlinear optical methods with AFM to detect ultrafast forces that arise when light and matter interact. Using AFM, the researchers measured the electrostatic force originating from light-induced electron motion in a dielectric. They observed changes in the force, caused by second-order nonlinear...