WAVELENGTH DEPENDENCE OF TWISTED NEMATIC LIQUID-CRYSTAL PHASE MODULATORS

Many twisted nematic liquid crystal spatial light modulators suffer fr om Limited phase modulation capability and coupled amplitude modulatio n. In particular, a phase modulation capability of less than 2 pi radi ans is a severe limitation. Phase modulation is wavelength dependent. We examine the effect of changing the operating wavelength on the phas e and amplitude modulation characteristics of a commercial liquid crys tal spatial light modulator. Comparisons are made with a double pass c onfiguration which can also increase the phase modulation capability. (C) 1998 Elsevier Science B.V. All rights reserved.