Optical limiting material

Although there have been great advances in covalent functionalization of fullerenes to obtain surface-modified fullerene derivatives or fullerene polymers, the application of these compounds in composites still remains unexplored, basically because of the low availability of these compounds [132]. However, until now, modified fullerene derivatives have been used to prepare composites with different polymers, including acrylic [133,134] or vinyl polymers [135], polystyrene [136], polyethylene [137], and polyimide [138,139], amongst others. These composite materials have found applications especially in the field of optoelectronics [140] in which the most important applications of the fullerene-polymer composites have been in the field of photovoltaic and optical-limiting materials [141]. The methods to covalently functionalize fullerenes and their application for composites or hybrid materials are very well established and they have set the foundations that later were applied to the covalent functionalization of other carbon nanostructures including CNTs and graphene. 

Asher S, Chang S-Y, Tse A, Liu L, Pan G, Wu Z, Li P. Optically nonlinear crystalline colloidal self assembled submicron periodic structures for optical limiters. Material Research Society Symposium Proceedings 1995, 374, 305-310. 

Fullerene has important properties as a nonlinear material, particularly as an optical limiting material with applications in device fabrication. The poor solubility of this material and the processing difficulties associated with it severely limit its direct application, however. One possibility of overcoming these disadvantages involves binding polymers on to Ceo to obtain fullerene-based polymeric materials with peculiar physical and/or chemical properties and good processability. 

Brunei M, Canva M, Bnm A, Chaput F, Malier L, Boilot J-P (1995) In Crane R, Lewis K, Stryland EV, Khoshnevisan M (eds) Materials for optical limiting materials. Research Society, Pittsbiugh, p 281... 

Crane, R. Lewis, K. Stryland, E. V., Khoshnevisan, M. Eds. Materials for Optical Limiting, Materials Research Society Symposium Proceedings, Vol. 374, Materials Research Society Pittsburgh, 1995. 

Figure 6.6 Molecular structure for (Au )-4-C = CC6H synthesis and properties of long conjugated organic optical limiting materials with different n -electron conjugation bridge structure were reported [50]. (Reproduced with permission from Elsevier.)...

Materials are also classified according to a particular phenomenon being considered. AppHcations exploiting off-resonance optical nonlinearities include electrooptic modulation, frequency generation, optical parametric oscillation, and optical self-focusing. AppHcations exploiting resonant optical nonlinearities include sensor protection and optical limiting, optical memory appHcations, etc. Because different appHcations have different transparency requirements, distinction between resonant and off-resonance phenomena are thus appHcation specific and somewhat arbitrary. 

Reverse saturable absorption is an increase in the absorption coefficient of a material that is proportional to pump intensity. This phenomenon typically involves the population of a strongly absorbing excited state and is the basis of optical limiters or sensor protection elements. A variety of electronic and molecular reorientation processes can give rise to reverse saturable absorption many materials exhibit this phenomenon, including fuUerenes, phthalocyanine compounds (qv), and organometaUic complexes. 

Within the limitations on the physical properties which generally restrict plastics to low precision optics, plastics materials have found wide applications in optical products that range from lights to binders for electroluminescent phosphors to fiber optics and lasers. They represent an easily worked material with a wide range of desirable optical properties in simple to complex shapes. In this review the discussion has been limited to the differences between plastics and optical glass materials and to some of the unique design possibilities that are especially important for plastics. Using the optical arts and the... 

One promising application for C60 is as an optical limiter. Optical limiters are used to protect people and materials from damage by high light intensities usually associated with intense pulsed sources. Optical limiting is accom-... 

Indeed, the timescale of the optical limiting effect in dendrimer nanocomposites is somewhat different than that found in other materials and this may be crucial to the understanding of the mechanism. Recent reports have investigated... 

Nonlinear optical organic materials such as porphyrins, dyes, and phthalocyanines provide optical limiting properties for photonic devices to control light frequency and intensity in a predictable manner. The optical limit of CNTs composites is saturated at CNTs exceeding 3.8wt% relative to the polymer mass (Chen et al., 2002). Polymer/ CNT composites could also be used to protect human eyes, for example, optical elements, optical sensors, and optical switching (Cao et al., 2002). 

Xu, Y., et al., A graphene hybrid material covalently functionalized with porphyrin Synthesis and optical limiting property. Advanced Materials, 2009. 21(12) p. 1275-1279. 

Nemykin et al. (2007) found a similar direct reaction between ferrocene (FcH) and tetracyano-ethylene (TCNE). The formation of a spectroscopically detected [FcH]+ [TCNE] was established. Cyanoferrocene and tricyanovinylferrocene as major and minor products were obtained, respectively. Although tricyanovinylferrocene was not the sole product of this reaction and its yield was approximately 30%, the direct method of its preparation was an important step toward materials for optically limiting devices. Untill now, the highly toxic chloromercurioferrocene was used for the preparation of tricyanovinylferrocene (Nemykin and Kobayashi 2001). 

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