Photonics optical switching

Winter, Underhill, and co-workers have published extensively on the cubic NLO properties of complexes of DT and related ligands,411 22 particularly those containing formally Ni11 centers. For example, time-resolved 1,064 nm DFWM was used to obtain resonantly enhanced values for group 10 complexes such as (157).411 15 The smaller of (157) compared with (156) is largely due to resonance effects since the absorption maximum of (157) is somewhat removed from the laser fundamental. However, figures of merit derived from measurements of 2 and linear and two-photon absorption (TPA) coefficients show that low optical losses render complexes such as (157) superior to (156)413 for potential all-optical switching applications.411 14... 

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). 

R. Mooshurger, et ah, Shaping the digital optical switch using evolution strategies, IEEE Photonics Technology Letters 9, 1184-1186 (1997). 

Losses still occur in the fibres developed for commercial use. Nonetheless, these have been reduced to a point where transmission over kilometres is possible. Along with transmission of information in telephone systems and similar applications, it has been suggested that optical devices may replace conventional electronics in more advanced applications such as computers. For such applications, it will be necessary to develop optical switches, amplifiers, and so on. In the last two decades, new materials have been developed that may form the basis of integrated optical circuits. These materials are photonic crystals. 

V 1 three-photon figure of merit for all-optical switching... 

Second-order non-linear optics continne to be an area of research becanse of its tremendous potential in the design of photon-based new materials for optical switching, data manipulation, and information processing [12]. 

Another important characteristic of semiconductors is their optical absorption properties. The optical properties of semiconductors are crucial to their uses as photovoltaic energy conversion devices, photonic detectors, light-emitting diodes, solid state lasers, and optical switches see Semiconductor Interfaces). Some semiconductors absorb both visible and ultraviolet light, while others only absorb photons in the... 

In a semiconductor, some of the most important electronic transitions arise from the optical excitation of an electron across the semiconductor band gap. This excitation leads to the promotion of an electron from an orbital in the valence band to an orbital in the conduction band. This fundamental and extremely important process is crucial to the use of semiconductors as photovoltaic devices, photonic detectors, and optical switches. It is possible to understand the optical properties of semiconductors using the band structure formalism described above. 

Polynuclear complexes, molecular dyads, triads, and other supermolecules composed of redox- and photo-active metal polypyridine units have a great promise as components of future molecular electronic or photonic devices as optical switches, relays, memories, etc. [38, 46],... 

Supermolecular species with imide acceptors have been designed as sophisticated optical switches [183, 238, 239], tetrad 56 being one example [238], These function via sequential two-photon absorptions that result in photoinduced electron transfer... 

Charge transfer NLO polymers offer the promise of truly unique properties properties that mimic the performance of photorefractive materials, but on ultrafast (picosecond) time scales. Such materials would enable ultrafast photonic applications (e.g. ultrafast optical switching and ultrafast image processing) that are impossible today with any known class of materials. 

Substantial progress has been accomplished in the fabrication of molecular and biomolecular optoelectronic devices. Light-activated molecular and bio-molecular systems have been integrated with electronic transducers, and the optical switching of the systems has been electronically transduced to the macroscopic environment. In particular, the photonic switching of an electron-transfer cascade has allowed the amplified electronic transduction of an input... 

---