An optically addressed spatial light modulation system includes a ferroelectric liquid crystal spatial light modulator. A writing light source irradiates a writing light for recording an image onto the spatial light modulator. A read-out light source irradiates a bias light for adjusting the sensitivity of the spatial light modulator and a read-out light for reading a recorded image from the spatial light modulator. An adjusting circuit is used to adjust the bias light intensity or irradiation time in synchronism with the writing light to increase the sensitivity of the spatial light modulator. A driving circuit supplies writing voltage signals to the spatial light modulator. The irradiation times of the write light and the bias light overlap with the application of the writing voltage signals for a predetermined time for adjusting the sensitivity of the spatial light modulator.