Natalie V. Kamanina

Optical investigations of a C70-doped 2-cyclooctylamino-5-nitropyridine–liquid crystal system

Thin holographic gratings in a C70-doped 2-cyclooctylamino-5-nitropyridine–liquid crystal system have been investigated under nano- and picosecond pulsed laser irradiation at a wavelength of 532 nm. From the results obtained, the nonlinear refractive index n2 and third-order susceptibility χ(3) have been determined. The potential use of the system studied in the modulation and generation of laser irradiation over the visible spectral range has been evaluated. The rotational ability of fullerene to strengthen the alignment of the LC molecule director has been discussed.

Optical limiters and diffraction elements based on a COANP-fullerene system: Nonlinear optical properties and quantum-chemical simulation

The results of optical study and quantum-chemical simulation of a conjugated organic system, 2-cyclooctylamino-5-nitropyridine (COANP)-fullerene, performed to determine its potential for application as a limiter of visible and near-IR laser radiation and as a material for diffraction elements in systems for reversible recording of optical information, are presented. Complexation between a COANP molecule and fullerene is considered as one of the main mechanisms responsible for the corresponding properties of this system. For the first time, nonlinear optical characteristics of COANP-C60 and COANP-C70 systems are comparatively studied and the intermolecular interaction between a COANP molecule and fullerene is analyzed on the quantum-chemical level.

Mechanisms of optical limiting in π-conjugated organic system: fullerene-doped polyimide

Mechanisms of the optical limiting effect in the fullerene-doped π-conjugated organic systems based on polyimide have been studied. Reverse saturable absorption, Forster mechanism, complex formation, and photoinduced change in the refractive index have been established to be responsible for the limitation of the laser radiation. Fullerene-doped polyimide can be applied to attenuate the laser power in the visible and near-infrared spectral ranges The potentialities of the system for conversion and modulation of the laser radiation have been discussed.

Laser-Induced Change in the Refractive Index in the Systems Based on Nanostructured Polyimide: Comparative Study with Other Photosensitive Structures

The fullerene- and nanotubes-doping effect on spectral and photorefractive properties of conjugated organic systems based on polyimide have been studied. A fullerene introduction in these materials has been used due to high electron affinity of fullerenes that allows the intermolecular donor-acceptor interaction to be reinforced. The nanotubes doping has been made due to a large increase in photoconductivity of the new composites. Drastic increase in delta n has been observed under condition of nanoobjects introduction. The data presented in the current study testified that these materials could be used as new reversible holographic recording elements, new optical limiting systems, as well as new high-speed switchers.

Peculiarities of optical limiting effect in π-conjugated organic systems based on 2-cyclooctylamino-5-nitropyridine doped with C70

The optical limiting effect in 2-cyclooctylamino-5-nitropyridine (COANP) doped with fullerenes has been investigated. The absorption saturation was found to begin at the incident energy density of 4 J cm-2. Optical limiting mechanisms have been specified in the fullerene-doped COANP compounds. The laser-induced refractive index and its influence on the optical limiting effect over the visible spectral range under nanosecond pulsed laser irradiation have been studied. Using the dynamic holographic technique, nonlinear coefficients n2 and χ(3) in C70-doped COANP have been first determined.

Refractive Index of Organic Systems Doped with Nano-Objects

Laser-induced change in the refractive index in fullerene- and nanotubes-doped conjugated structures have been investigated by the dynamic holographic technique. Nonlinear refractive index n 2 and nonlinear optical susceptibility χ(3) of the compounds have been calculated. The role of the high frequency Kerr photorefractive effect in the holographic grating recording under nanosecond laser irradiation has been discussed. A niche of the organic materials doped with nano-objects has been found among other nonlinear optical systems. The nano-object-stimulated improvement of laser strength of materials has been shown.

Self-Organization and Dynamic Characteristics Study of Nanostructured Liquid Crystal Compounds

Fullerene-doped liquid crystal compounds have been considered as new nanostructured materials with promising photosensitivity and speed parameters. Self-organization in liquid crystal mesophase based on charge-transfer complexes between an organic donor and fullerene has been investigated. The switch-on time of 50 μs has been obtained. The results are discussed from the viewpoint of increasing the system polarizability and a possible transition from the nematic phase to the smectic one, which is caused by a complex formation.

Nonlinear optical coefficients of polyimide doped with fullerenes

Laser-induced refractive index in fullerene-doped polyimide 6B has been investigated by the dynamic holographic technique. Nonlinear refractive index n2 and nonlinear optical susceptibility χ (3) of the compounds have been calculated. The role of spectral, thermal, and photorefractive effects in the holograpic grating recording under nano- and picosecond pulsed laser irradiation has been discussed. The place of the materials studied has been found among other nonlinear optical systems.

Optical properties of the fullerene-doped polyimide in the near infrared

A promising structure based on fullerene-doped polyimide has been developed and tested to create new optical limiting (OL) and holographic recording systems in the near infrared (1315 nm). From reversible holographic recording experiment data, the laser-induced change in the refractive index has been calculated. The results predict that fullerene-doped polyimide 6B can be used as an effective holographic recording system and a nonlinear absorber in the near infrared spectral range.

Light-induced variation in the refractive index in a polyimide-fullerene system

Light-induced variation in the refractive index of the polyimide-C70 system is studied. This process makes a contribution to the nonlinear transmission of this system in the study of the optical limitation of laser radiation and determines the prospects of using this system as a nonlinear holographic medium for reversible data storage. The nonlinear optical coefficients n2 and χ(3) of fullerene-sensitized polyimides are determined for the first time by the methods of dynamic holography.