tailieunhanh - The propagation of the electromagnetic wave in multilayers structures composed from cholesteric liquid crystals under the influence of the external electric field

The propagation of the electromagnetic wave in multilayers structures composed from cholesteric liquid crystals under the influence of the external electric field. The tensor solution for the electromagnetic wave being in quadrature with the surface of the cholesteric liquid crystal under the influence of the external electric field along axis of swing of crystal, has been found. | Communications in Physics, Vol. 19, No. 1 (2009), pp. 26-32 THE PROPAGATION OF THE ELECTROMAGNETIC WAVE IN MULTILAYERS STRUCTURES COMPOSED FROM CHOLESTERIC LIQUID CRYSTALS UNDER THE INFLUENCE OF THE EXTERNAL ELECTRIC FIELD PHO THI NGUYET HANG Institute of Engineering Physics, Hanoi University of Technology PHAM THUY DUNG Vietnam Research Institute of Electronics, Informatics, Automation Abstract. The tensor solution for the electromagnetic wave being in quadrature with the surface of the cholesteric liquid crystal under the influence of the external electric field along axis of swing of crystal, has been found. Description of the reflection, transmission of the electromagnetic wave in multilayer structures composed from cholesteric liquid crystals have been shown. Futher the dependence of the reflection spectrum on the polarization of the incident beam and magnitude of the external electric field are determined. I. INTRODUCTION Recently, liquid crystal in general and cholesteric liquid crystal, in particular, had attracted great interests from both theoreticians and experimenters since their physical properties are enable to be changed under the influence of some external actions, such as electromagnetic field, stresses, temperature, . . . This significant property has been widely applied in various technological devices. A sery of recent works have studied the effects of external field on twist step of cholesteric liquid crystal [1-4], however all these works had not consider the external effects on propagative characterizes of electromagnetic wave on liquid crystal. Noticed that the cholesteric liquid crystal is stratified anisotropic material, so in the general case of the oblique electromagnetic wave in the crystal plate, the exactly solution of the Maxwell’s equations can not be found. Theories of the propagation of the electromagnetic wave in the cholesteric liquid crystal had been shown in the works [3-9]. These authors had used various approximate .