Floating-element shear-stress sensor using an optical Moire transduction technique

A sensor system for measuring shear-stress, comprising:

• A Moiré interferometric-based shear-stress sensor including a substrate support, said substrate including a first optical grating disposed in or on said substrate, said first grating having a plurality of features defining a first spatial period, and a floating element having a second optical grating disposed in or on said floating element, said second grating having a plurality of features defining a second spatial period, said floating element suspended over said first grating and flexibly connected to said substrate with compliant springs, wherein said first and second gratings are in an optical path with one another, said sensor upon irradiation forming a Moiré fringe pattern which relates to a shear-stress induced translation of said floating element;
• a light source for irradiating said sensor with electromagnetic radiation, and
• a detector for measuring fringe patterns resulting from reflections of said radiation from said first and second grating.