Single-pass thin-film electro-optic modulator based on an organic molecular salt

Single crystal films of 4'-dimethylamino-N-methyl-4-stilbazolium tosylate ( DAST) with excellent optical quality have been prepared by modified shear m ethod. Electro-optic modulation for light propagating perpendicular to the film surface was measured at a wavelength (720 nm) where absorption is smal l. Very large electro-optic modulation (20%) was demonstrated in a 3 mu m t hick film at a low ac field (1 V/mu m, at 4 kHz). Electro-optic modulation in such thin films is suitable for a wide range of applications in free-spa ce interconnects and various modulator structures with light propagating pe rpendicular to the film. The magnitude of the electro-optic coefficient at 720 nm, r(11)similar to 530 pm/V, is significantly larger than that of bulk crystals. (C) 1999 American Institute of Physics. [S0003-6951(99)02305-0].