HIGH-RESOLUTION ANGULAR AND DISPLACEMENT SENSING BASED ON THE EXCITATION OF SURFACE PLASMA-WAVES

The possibility of building angular and displacement sensors based on the phenomenon of attenuated total reflection (ATR) is explored both n umerically and experimentally. ATR occurs when a surface wave is excit ed by an incoming TM electromagnetic wave through a resonant phase-mat ching process, as in the Kretschmann coupling scheme. The reflected in tensity strongly depends on the angle of incidence of the beam. We fir st show some computations of the sensitivity and the linearity of an A TR-based sensor, then proceed to the experiment, illustrating how an a ngular resolution of the order of 0.1 are sec can be obtained with mod erate effort. Finally me show how the sensor, combined with a simple o ptical arrangement, can be used to detect and measure nanometric displ acements, as those provided by piezoelectric actuators. (C) 1997 Optic al Society of America.