Magnetically tunable room-temperature 2π liquid crystal terahertz phase shifter

Tunable phase shift up to 360degrees at 1 THz is achieved with a liquid crystal (LC) device. The key to this design is (1) the use of a nematic LC, E7, which exhibits a birefringence of similar to0.17 (0.2-1.2 THz); (2) a LC cell (3-mm in thickness) with sandwiched structure to increase the interaction length while minimizing interface Fresnel losses; and (3) the use of magnetic field to align the thick LC cell and achieve continuous tuning of phase from 0 to 360degrees. This device can be operated over a broad range near room temperature. (C) 2004 Optical Society of America.