Fast optical switching by a laser-manipulated microdroplet of liquid crystal

We demonstrate the feasibility of an all-optical liquid-crystal (LC) switch with submillisecond switching time. This switch is realized by optical manipulation of a three-dimensionally trapped microscopic nematic LC droplet using an "optical tweezers." Transmission of a polarizer/LC droplet/analyzer system can be modulated at frequencies as high as 10³ Hz, a faster response than that of a nematic LC demonstrated so far. The response corresponds to a submillisecond switching time when the LC droplet is rotated by an angle of π/4. The alignment of the LC droplet to the plane of the incident plane-poiarized beam is also demonstrated.