Optimization of all optical switching process by using E7 liquid crystal twisted cell in pump-Probe scheme

All optical switching was performed using twisted cell with polymer alignment layer and filled with E7 liquid crystal. I showed that different characteristics of all optical switches such as contrast ratio and response time can be affected by parameters such as angle between pump and probe beam, wavelength and polarization of pump beam as well. Indeed, polymer alignment layer plays a significant role in switching process which leads to formation of charge layer and screening field. A mechanism for the effect of the angle between pump and probe beam and polarization of pump beam on switching process has been proposed in this experimental work. Furthermore, the effect of pump beam in discharging screening field and reducing Friedericksz transition threshold voltage as a consequence has been demonstrated.