Vacuum deposition of chiral sculptured thin films with high optical activity

We present the technique of bideposition to realize thin-film helicoidal bi anisotropic mediums (TFHBM's) that exhibit high optical activity. Ne show, by experiment as well as by simulation, that the optical rotation produced by these chiral sculptured. thin films is roughly proportional to the squar e of the local linear birefringence. Experimental measurements on bideposit ed TFHBM's of titanium oxide yield a typical value of 5 degrees/mu m for th e effective specific rotation in the short-wavelength regime; the correspon ding value determined for the standard unideposited TFHBM's is 1 degrees/mu m. Both types of TFHBM's are highly optically active in comparison with qu artz, fluorite films, and cholesteric liquid crystals. Bideposited TFHBM's will lend themselves to many different types of optical devices. (C) 2000 O ptical Society of America.