Coherent gradient sensing microscopy (micro-CGS): A microscale curvature detection technique

Micro-CGS, a full-field, real-time, micro-interferometric technique for quantitative imaging is introduced. Micro-CGS extends the capabilities of the large-scale shearing interferometric technique of Coherent Gradient Sensing (CGS) in the micro-scale. The experimental setup is detailed and resulting interferograms are shown. A digital image processing program is created to compute specimen curvature from recorded fringe patterns. The experimental method is validated by the successful measurement of the curvature of 30 μm glass microspheres.

Research highlights
► Micro-CGS is a full-field micro-interferometric technique for quantitative imaging of curvature at the micro-scale.
► Micro-CGS is a non-invasive real-time technique.
► Micro-CGS is not sensitive to rigid body motion because it provides the out-of-plane gradient of the specimen surface topography.