| 摘要 |
Polarisation Controller A polarisation controller comprises at least one stack of nematic liquid crystal cells arranged such that radiation incident on the stack will pass through each cell in the stack in sequence. Synchronised electric or magnetic fields are applied across the cells so as to change the phase retardation of the radiation transmitted through each cell by a chosen amount, the optical axes of the cells being oriented with respect to each other such that the polarisation of radiation incident on the controller is caused by the controller to change from a first state to a second state. |
