9632874 Fainman The coming decade will see a revolution in computing and communications technology. Existing telecommunication switching networks are inadequate for the emerging integrated services digital network which will use the tremendous point-to-point bandwidth of optical fiber. New technologies are necessary to provide ultra-high bandwidth switching capability to keep pace with the rapid advances in data transmission rates. The current trend in developing high performance computing and communication systems is towards increasing parallelism in addition to speed. Free space optical technology, being inherently three-dimensional, is attractive for interconnecting these highly parallel systems. Conventional diffractive optical elements (DOEs) use a phase profile to deflect and shape an incident optical wavefront. These elements are beginning to be incorporated as low cost beam splitters and aberration correctors in previously all-refractive optical products. The second generation of DOEs are elements that discriminate among the incident light by polarization or wavelength. Our group has done pioneering research into these optical elements, having fabricated the first planar DOE which reconstruct a different pattern depending on the incident polarization, and another which vanishes at a specified wavelength. With these elements packaging size and cost of complex optical and optoelectronic systems can be significantly reduced. Here, we propose to begin an investigation of the third generation of DOE to produce electrically programmable response as well as continue the investigation of novel DOE devices with multifunctionality in polarization and color. These DOEs are useful for construction of transparent switching fabrics allowing the routing of data between input and output ports at bandwidths independent of the switching speed of the individual switching element. In addition, such programmable DOEs will play an important role for packaging of manufacturable optoelectronic systems be cause they combine the functionality of several optical components with built-in relative alignment. Such elements can serve as active alignment components for packaging large scale optoelectronic systems. Programmable DOEs that allow fast, efficient, high-resolution, random-access optical beam steering and dynamic focusing are required by numerous optoelectronic system applications including 2-D and 3-D displays, 3-D optical memories, programmable optical interconnects, optical routers, and 3-D optical imaging. The goal of this proposal is to conduct basic research towards development of DOEs with multifunctionality and DOEs with programmability for construction of transparent switching fabric and for packaging of manufacturable optoelectronic systems. The proposed approach is based on developing near-field diffractive optical devices that utilize subwavelength nanostructures to create artificial dielectrics with optical properties that enable multifunctionality and electrical programmability. Furthermore, by employing the computer generated hologram design approaches, an array of such near-field optical devices can be used to create DOEs that possess electrical programmability of their far field spatial impulse response. The fabrication of these elements will leverage from the advances in microelectronics technology using E-beam lithography, photolithography, ion beam etching, ion implantation, etc. The specific objectives of this proposal include rigorous modeling, design, fabrication and testing of near-field diffractive optical devices that utilize composite passive and electrooptic subwavelength nanostructures to create artificial dielectrics with multifunctionality and electrical programmability. Our ultimate objective is to construct an array of such devices to realize DOEs with electrically programmable far field impulse response. ***
