Abstract: Fiber optic switches using layers of cholesteric or chiral nematic liquid crystals (CLCs) are disclosed. The CLC layer acts both as a polarization beamsplitter and as a reflector by decomposing incoming unpolarized light into two orthogonal circularly polarized components. In a number of embodiments, switchable waveplates are employed to controllably switch the polarization direction of each of the polarization components. The components are then reflected back toward the CLC layer where they are recombined into a transmitted unpolarized beam. The direction of transmission depends on the circular sense of the polarized components, and therefore on the state of the switchable waveplates. In other embodiments, the CLCs are used actively by selectively exposing them to electric or magnetic fields or to heat which cause a phase change that temporarily neutralizes the circular polarization effect. In this manner, the CLCs can be used as switch elements themselves.

Abstract: Disclosed herein is an analytical apparatus comprising a gas chromatograph, a mass spectrometer, and an interface connecting the two. The mass spectrometer comprises a variable energy ion beam source, a magnetic sector of substantially fixed magnetic field for deflecting the ions in the ion beam according to their momentum, and a detector for detecting those ions within the ion beams which have been deflected by a given angle by the magnetic sector. The variable energy ion source comprises a repeller electrode, a first low energy alignment electrode coacting with the repeller electrode to define an ion-forming region, an inlet means for introducing gas into the ion-forming region, means for forming an electron beam in the ion-forming region, a second high energy alignment electrode, and an entrance electrode separating the ion beam source from the magnetic sector.