Electrical origin and compensation for two sources of degradation of the spatial frequency response exhibited by liquid crystal displays

In this paper we give quantitative evidence for the electrical origin of two optical phenomena exhibited by commercial liquid crystal displays (LCDs) which affect its performance in spatial light modulation applications such as programmable diffractive optical elements (DOEs). These two optical phenomena are associated with a degradation of the spatial frequency response of the LCD. The first optical effect is the existence of spurious diffraction orders located halfway between the vertical diffraction orders produced by the pixelation of the LCD. The second is the dependence of the phase modulation depth on the horizontal local spatial frequency when displaying phase-only DOEs. Electrical measurements for the signal addressed to the LCDs are shown which demonstrate that they are directly related with these two optical phenomena. We also show how the spurious orders can be eliminated with a proper balance of the electrical signal, and we discuss strategies to compensate for the effects of the anamorphic and frequency dependent phase modulation depth. © 2007 Society of Photo-Optical Instrumentation Engineers.