Integrated deformable mirror on silicon for optical data storage

This paper reports the design, fabrication and opto-mechanical characterization of a deformable mirror to correct spherical aberration in future optical data storage standard (Blu-Ray Disc). The integrated mirror is realized in standard semiconductor technology to produce very low cost devices. The device is based on the electrostatic actuation of a 10 mu m thick silicon membrane (4 mm diameter) obtained from a 4' SOI wafer glued with polymer paste over concentric or hexagonal electrodes obtained from another 4' silicon wafer. Optical wavefront measurements compared with theoretical calculations demonstrate that an applied voltage of only 40 V on the three concentric electrodes allow to perfectly correct aberrations. Moreover we showed that the shape of the optical deformation induced by the mirror can precisely be controlled by the design of electrodes and applied voltages. A Peak to Valley optical deformation up to 4 mu m can be achieved with an applied voltage of only 70 V. Finally dynamic measurement showed that the device is able to work at a frequency of 100 Hz that is higher that needed for foreseen application.