Figure 2

Colour maps showing the variation in the Speckle Contrast, C (legend shown on the secondary axis) for different amplitudes and frequencies of a square wave electric field applied to the chiral nematic LC device (E7 + 2.5 wt% BDH1281, pitch 517 nm). (a) Electric field and frequency increments of 2 Vµm⁻¹ and 20 Hz, respectively. (b) higher resolution measurements–electric field and frequency increments of 0.2 Vµm⁻¹ and 5 Hz, respectively. The black boxes in (a) and (b) represent the electric fields corresponding to the smallest speckle contrast ratio, C (maximum speckle reduction). All measurements were carried out at 25 °C using a 20 µm-thick device.