The fabrication and characterization of a Silicon based photo-controlled deformable mirror (PCDM) for spatial light modulation and wavefront control is reported. The device is a membrane mirror based on a 1-inch monolithic non-pixelated Silicon photoconductive substrate with a transparent ITO electrode on one side coupled with a 5 µm thick nitrocellulose membrane. The device is driven applying an AC voltage and it is characterized by measuring the generated wavefront using a Shack-Hartmann wavefront sensor. Upon uniform illumination with a NIR LED, the deformation increases with the voltage applied, its frequency and the light intensity. The maximum deformation achieved is approximately 2 µm PtV (wavefront). The repeatability of the induced deformation is also evaluated together with its time stability, proving that the device is reliable in the working conditions. The response time is evaluated and it is in the range of 10 ms. The device is suitable for an efficient adaptable focusing element with an important focus control.