Synthesis of double-conjugated-segment molecules and their application as ultra-broad two-photon-absorption optical limiters
作者:Junxiang Zhang、Yiping Cui、Mingliang Wang、Juzheng Liu
DOI:10.1039/b208190c
日期:2002.10.18
A series of novel double-conjugated-segment molecules, in which two conjugated segments are separated by an ether chain, were synthesized; these compounds provide a very broad two-photon absorption spectral range, which satisfies an urgent need in the optical limiting area.
In a preferred embodiment this invention provides a second order nonlinear optical film medium which consists of a thermoplastic copolymer which has a crystallographic molecular alignment, and a net dipolar molecular orientation normal to the film plane. The crystallographic molecular alignment is formed by axial mechanical stressing, and the dipolar molecular orientation is induced by an electric or magnetic field. Illustrative of an invention polymer is a copolymer of vinylidene fluoride and 4-[N-(10-methacroyloxydecyl)]-4'-nitrostilbene: ##STR1##
A three-dimensional electro-optic waveguide is formed as a channel in a structure made of an organic non-linear optical polymer. A poling electric field is maintained in a portion of the polymer structure defining the channel, and the polymer structure is heated above the glass-transition temperature to enable dipolar moieties of the polymer to become aligned by the poling field. Heating continues until the dipolar moieties are sufficiently aligned to produce a higher index of refraction in the channel portion than in adjacent cladding portions of the polymer structure for at least one polarization of optical radiation propagating through the channel. The poling field is maintained as the polymer structure is then cooled below glass-transition temperature, thereby preserving alignment of the dipolar moieties (and hence preserving the differential index of refraction) in the channel portion of the polymer structure. Guided modes of optical radiation of at least one polarization can be supported in the channel.
This invention provides novel isotropic acrylic copolymers which exhibit nonlinear optical response, and which have utility as a transparent optical component in optical light switch and light modulator devices. An invention isotropic acrylic copolymer is illustrated by the following structure: ##STR1##
A waveguiding media of polymeric materials is disclosed and claimed. In a preferred embodiment both core and cladding include X.sup.(2) materials poled to a non-centrosymmetric structure. Materials are selected so that the index difference between core and cladding remains relatively constant before and after poling so as to allow for efficient fabrication.