Status of the ALMY semitransparent, amorphous silicon sensors for optical position monitoring systems

Semitransparent optoelectronic position sensors (‘ALMY sensors’) have been developed for high-precision multipoint alignment monitoring systems. The thin-film amorphous silicon strip sensors provide up to 90% transmittance for visible laser light and a position measurement accuracy of better than 5 μm over sensitive areas of several square centimeters. We report about the results of the recent optimization of the sensor performance and of the readout electronics.