Computer-controlled stabilization of mode of single-frequency He-Ne laser with thin-film absorber

The system of single -frequency He-Ne laser, with a thin-film selector, working with stabilization of frequency of output beam power is presented. The stabilization loop includes the Amstrad 6128 computer connected with digital system for piezoceramic control that has been designed for this purpose. Construction of shifters ensuring transverse and longitudinal effects are shown and results of their examinations are discussed. The ranges of selection of a single longitudinal mode and measurement results of the output power stabilty are also given.