Systematic characterization of optical beam deflection measurement system for micro and nanomechanical systems

Optical beam deflection (OBD) measurement method is very popular in various types of scanning probe microscopy (SPM) and micro/nanomechanical sensors to measure a mechanical motion. This paper reports the detail design and implementation of a very low drift (2 nm over 1000 s), high bandwidth (40 MHz) and low noise (15 fm/VHz) OBD measurement setup that can be used in metrological SPM. The noise, bandwidth and stability of the setup and the thermo-mechanical behavior of SPM cantilevers were systematically characterized. The influences of optical beam spot size, power of the laser beam and the type of position sensitive detector on the total measurement noise for different preamplifications were analyzed in detail. Consequently, recommendations for further improvements of the OBD systems in SPMs and MEMS sensors are given. The results can be used in future high speed, high accurate and low drift SPMs and MEMS sensors applications