Detection of foreign materials in prepregs

The research proposed here is built on the recent successful fabrication of the first electrically-pumped III-nitride micro-size LED, micro-size LED arrays, and waveguides by the principal investigator's research group at Kansas State University. Newphysical phenomena and properties begin to dominate as the device size scale approaches the wavelength of the light they emit, transmit, and detect. In this realm, quantum nature of light dominates, enabling more efficient and fast devices. Themicro-size lasers and LEDs allow the ability to create arrays of individually controllable pixels on a single chip. Potentially these micro-size light emitters can operate as large arrays or independently to communicate millions of messages (or images) atthe same time. Such vast numbers of micro-lasers could be used to read, write or process two-dimensional images, and to speed the flow of information between memory and processing chips as well as between different computer boards. Micro-cavity lasersbased on III-nitrides offer additional benefits including shorter emission wavelengths (higher optical storage density and resolution), the ability to operate at much higher voltages and power levels due to their mechanical hardness and larger band gaps,and high speed due to the intrinsically rapid radiative recombination rates. The objectives of this Phase I research are to further develop the III-nitride micro-cavity photonic device technologies and to demonstrate the feasibility for achievingelectrical pumped microcavity lasers as well as the integration of miniaturized light emitters with waveguides.III-nitride microdisk and microring lasers and arrays developed here are not only useful in compact displays, but also useful as emitters forremote free space functions and in short distance optical communication and high resolution and high speed optical links. By combining millions of the laser beams of these micro-lasers together, one may also obtain extremely high power lasers with verysmall size and simple designing. When an array of III-nitride microcavities is reverse biased, it can be modified as a miniaturized UV detector array. Thus III-nitride microcavity photonic devices open many important applications such as opticalcommunications, signal and image processing, optical interconnects, computing, enhanced energy conversion and storage, chemical- and biohazard substances and weapon detection and warning and medical. III-nitride LED technologies will pave the way for fullcolor displays and mixing three primary colors to obtain white LEDs for general lighting. The P.I.s have already developed a novel LED architecture that utilizes microdisk cavity LEDs and can boast the emission efficiency by more than 60%. Findingmethods for increasing LED efficiencies is a key step for many applications, including full color displays and general lighting. There is an enormous market interest in the area of general lighting based on LEDs.