Optical devices, non-linear

Finally an LDA calculation was also performed for a polyparaphenylene (PPP) helix.100 This conducting polymer (if doped) is quite interesting for its applications in light emitting diodes101 (especially because it emits blue light102), in field-effect transistors103 and in non-linear optical devices.104... 

The Surface Plasmon Resonance (SPR) technique is presented as a sensitive system of measurement, and the underlying physical mechanism is described. The method is ideal for determining the linear and non-linear optical properties of dielectric media in thin film form, specifically those prepared by the Langmuir-Blodgett (LB) method. The LB method of film deposition and its inherent advantages as a process for non-linear optical device fabrication are discussed briefly. 

Molecules 19-22 are model systems for a related project, which aims to incorporate D-a-A systems into LB-film-forming diacetylenes, which may be polymerized in situ on the film balance, for the purpose of preparing new systems with promise as non-linear optical devices. Interestingly, 19-22 form Z-type multilayers on a glass substrate (the film subphase is held at 5° C but the slide is at room temperature). An attempt was made to see whether any second harmonic signals could be detected from Z multilayers of 21, but the result was negative [47]. 

This type of up-conversion is to be distinguished from laser harmonic generation obtained by non-linear optical devices. In the undulator case, the coherent output power is generated by loss of electron kinetic energy, i.e. an energy transfer process, rather than taken from the laser pump. 

Since the copolymers, Copoly 1-3 [32b,33], and PAE-2 and its analogues [8b,d,35a,b] have large values, preparation of non-linear optical devices using the materials is expected. Recently, a wave guide using PAE-2 has been prepared [35b]. 

Electrochromic devices, where a transparent window can be turned opaque at selected regions of the electromagnetic spectrum under a potential, are another area in which PA copolymers and substituted PAs may have potential applications. Promising research opportunities also exist in the fabrication of PA-based controlled-release devices, non-linear optical devices, light-emitting diodes, and radar shielding. The readers are encouraged to consult some older [191-196] and more recent [197-199] review articles on these subjects. 

The intense fluorescence of laser-dyes embodied in these thin-film glasses, the simplicity to cast these sol-gel glasses in a multilayered sequence of tailored indices of refraction and the waveguide properties observed in such assemblies imply that such multilayered films may be constructed into a surface-laser. Currently, we are examining these structures as the core of a two dimensional laser and other non-linear optical devices. 

Ferroelectric combs, if realizable in device form, may have valuable applications Le Barny and Dubois discuss their potential in the areas of display devices, transducers, pyroelectric detectors and non-linear optical devices (see below). 

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