Alignment cells for modulating both amplitude and phase in spatial light modulators

A spatial light modulator comprising:

• a layer of liquid crystals, with a predefined thickness, sandwiched between a transparent electrode layer and a reflecting electrode layer, wherein the reflecting electrode comprises an array of pixel electrodes, each controlling one of pixels in two-dimensional (2D) array, and is built on a silicon substrate;
• and
• an alignment layer, deposed on top of the layer of liquid crystals, including a plurality of alignment cells in rows and columns, wherein a first group of the alignment cells and a second group of the alignment cells are oriented with 45 degrees apart, light impinging upon the first group and second group of the alignment cells at the same time, the light going through the first group of the alignment cells and the liquid crystals is modulated in amplitude thereof and the light going through the second group of the alignment cells and the liquid crystals is modulated in phase thereof.