This paper presents the development of a floating-element shear stress sensor that permits the direct measurement of skin friction based on geometric Moiré interferometry. The sensor was fabricated using an aligned waferbond/thin-back process producing optical gratings on the backside of a floating element and on the top surface of the support wafer. Experimental characterization indicates a static sensitivity of 0.26 μm/Pa, a resonant frequency of 1.7 kHz, and a noise floor of 6.2 mPa/rtHz.
