摘要:

In this work, we study the response of Long Period Fiber Gratings (LPG) to an external Nematic Liquid Crystal medium. By a coupling between the fundamental mode of the core and the cladding modes of the fiber, losses occure at different wavelengths. The spectral position and the intensity of those losses depending on the index of the external medium, one can expect that different orientations of the NLC will induce a modification of the response of LPG. To check this assumption, we have realised two types of experiments: In a first time, we have studied the response of LPG to different treatments of the fiber. In particular, we present for the first time a method to obtain a planar alignment directly on the fiber. It will then be demonstrated that the response of LPG can be modified by Fredericksz reorientation of NLC, creating new opportunities in telecommunications networks.

ISSN:1058-725X    

DOI:10.1080/10587259808024409

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Poly (vinyl cinnamates) are known to be phototransformable. We present in this work the Raman spectroscopy evidence of phototransformation in the case of poly (vinyl-para-fluoro-cinnamate). The relative intensity evolution of the C˭C double bond stretching mode reflects strongly the polymer transformation under irradiation. Some other modes are also affected but the effects are less marked. We show also that phototransformation occurs both under UV and visible linearly polarized radiations.

ISSN:1058-725X    

DOI:10.1080/10587259808024410

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

High power laser (P∼106W/cm2) induced “domain”-like reorientation in homogeneously oriented by silicon monoxide dye doped liquid crystals (DDLC) has been observed. Reorientation can be accompanied with writing of static gratings that are induced by a radiation on monoxide layer surface.

ISSN:1058-725X    

DOI:10.1080/10587259808024411

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Wave-front conjugation (WFC) in four-wave interaction (FWI) of monopulse radiation of ruby laser in dye-doped liquid crystals (DDLC) was obtained. The amplification of conjugation wave was observed. The amplitude gratings and the phase gratings on thermal nonlinearity give the contribution in wave front conjugation.

ISSN:1058-725X    

DOI:10.1080/10587259808024412

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Two mechanisms of optical response in liquid crystals (LC) of homologous series 4-n-butyl-4′-n-alkoxyazobenzenes (BAAB), namely the photochemical phase transition and reorientation in bulk of LC are considered. The temporal parameters of writing (Ar+laser) and erasing (He-Ne laser) of information on BAAB on the basis of photoinduced phase transition are presented. The phenomenon of reorientation of BAAB molecules in planar oriented layer induced with second of Nd:YAG laser in directions orthogonal to initial alignment was revealed.

ISSN:1058-725X    

DOI:10.1080/10587259808024413

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:1058-725X    

DOI:10.1080/10587259808024378

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor