LCOS-SLM has replaced PPM.  Please visit the LCOS page for more information about this series. Replacement parts for PPM will be available through 2010.

The PPM, Programmable Phase Modulator, is an electrically-addressed phase modulator using an optically-addressed PAL-SLM, Parallel Aligned Nematic Liquid Crystal Spatial Light Modulator, optially coupled through a lens to an electrically addressed intensity modulator.  Conventional optically-addressed modulators have difficulty in a computer control, while electrically-addressed modulators have drawbacks that unwanted diffraction light is generated due to the pixel structure in the electrical signal input section and that the light utilization efficiency is low due to its small fill factor. The PPM uses an LCD to enable the computer control easily and also employs a newly developed optical system to eliminate the unwanted diffraction light originating from the LCD pixel structure. Moreover the PPM offers large phase modulation characteristics, making it possible to develop adaptive optics that uses optical diffraction and spatial phase control.