Devices photonic switching

Lytel, R., Applications of electro-optic polymers to integrated optics, SPIE Proc. Nonlinear Opt. Mater. Devices Photonic Switch, 1216, 31 (1990). 

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. 

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... 

K. Matyjaszewski in 1990. After he joined Prof. C. K. Ober s research group in the Department of Materials Science Engineering at Cornell University as a postdoctoral associate for 2 years, working with the development and applications of optoelectronic polymers, he returned to Korea in 1993 and worked to develop polymeric photonic devices as a Project Leader at the Photonic Switching Section at the Electronics Telecommunications Research Institute (ETRI) for IV2 years. He became an Assistant Professor in the Department of Polymer Science Engineering at Hannam University. Professor Kim was the recipient of the Excellent Scientist Award of the Korean Chemical Society for Polymer Chemistry in 1998. He has published more than 95 communications, papers, and review articles, a number of chapters in books, and 13 patents. 

Krug, W., Miao, E., Beranek, M., Rochford, K., Zanoni, R., and Stegman, G., Optical properties of strip-loaded polydiacetylene waveguides, in Nonlinear Optical Materials and Devices for Photonic Switching (Proc. SPIE, 1216), Peygambarian, N., Ed., SPIE, Bellingham, 1990, 226. 

This technology has also paved the way for microelectromechanical systems (MEMS). MEMS technology can produce new photonic switching devices and routers for the... 

New natural polymers based on synthesis from renewable resources, improved recyclability based on retrosynthesis to reusable precursors, and molecular suicide switches to initiate biodegradation on demand are the exciting areas in polymer science. In the area of biomolecular materials, new materials for implants with improved durability and biocompatibility, light-harvesting materials based on biomimicry of photosynthetic systems, and biosensors for analysis and artificial enzymes for bioremediation will present the breakthrough opportunities. Finally, in the field of electronics and photonics, the new challenges are molecular switches, transistors, and other electronic components molecular photoad-dressable memory devices and ferroelectrics and ferromagnets based on nonmetals. 

A dim light emits fewer photons than does a bright light. So a dimmer switch is merely a device for varying the flux of photons emitted by a light bulb. The energy per photon is not significantly altered in this way. 

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). 

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. 

If the operation of the devices considered above on their specific substrate (photon, electron, ion) is triggered by external optical, electrical or chemical stimuli, their features may be switched between two (or more) states presenting different characteristics. Such switching devices are therefore formed by two main components a trigger, the switching unit, activated by an external stimulus and a substrate, the switched species they should operate with efficiency, reversibility and resistance to fatigue. 

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