RADLAB Seminar

Plasmonics, Fluorescence Enhancement, Photonic Jets, Gradient Index Media, Nonlinear materials and their applications to Detector/Imaging Enhancement, Compressive Sensing, Optical Limiters, On-Chip Optical Communications and Processing

Nicholaos I. LimberopoulosAir Force Research Laboratory (AFRL)

Plasmonics have the potential to enhance the performance of detectors. A thermal metal dewetting process was developed which can be easily scaled for high throughput production. Through this process, plasmonic nanostructures were fabricated providing broadband plasmon resonance tunable over a 1Â µm wavelength range. In addition, sub-diffraction-limit imaging is reported using subwavelength surface roughness on a metal film. Ions of rare earth metals are utilized for the preparation and optimization of infrared fluorescent ceramics as well as their thin film incorporation into plasmonic systems for fluorescent imaging with enhanced efficiency. Photonic jets are used for super-resolution imaging as well as enhancing the performance of strained-layer superlattice (SLS) infrared (IR) photodiodes in the midwave-infrared spectral band (3-5µm) for compressive sensing and imaging.
Gradient Index Media have multiple applications for controlling the wave propagation and harvesting its received energy or processing its embedded data. A nanofabrication process was developed to produce a Luneburg lens on silicon, to operate in the optical regime, with feature sizes smaller than 100nm. The enhanced focused energy of the Luneburg lens was clearly demonstrated. In addition, a mechanism of thermal tunability of such devices is proposed. A process to deposit Black Aluminum, a novel anti-reflective absorbing coating, has been discovered by our group. Black Aluminum films were utilized on our pyroelectric sensors and significant enhancement in the pyroelectric response was demonstrated. Nonlinear materials are utilized in a unique way to produce novel reflective optical limiters.

Nicholaos I. Limberopoulos is currently assigned to the Electro-Optical Components branch (RYDP) at the Air Force Research Laboratory (AFRL) as the Electronics Research Engineer. The branch performs basic and applied research on emerging EO/IR sensing technologies to overcome the Air Force's anti-access/area denial challenge and provide world class technology to our Nation's warfighters.
He obtained his MEng degree in Electronic and Communication Engineering from the University of Bath, England, in 1998, specialized in Digital Signal Processing and Genetic Algorithm Optimization. He began his career in 1999 working in the industry as an Electrical Engineer for C&M Corporation in New Product Development (Datacom, Mobilecom, Medical, Barcode, and Power products) and as an industry standard technical committee contributor in the development of test procedures and specifications of upcoming new products. He was promoted to Sr. Development/Electrical Engineer in 2002 and his role expanded to include technical sales, leading a multi-million dollar customer account, as well as lead of the quality group electrical testing. During his Ph.D. studies, his role included teaching and research in the areas of Electronics, and Electromagnetics of Complex Media. He obtained his Ph.D. degree from the University of Massachusetts at Lowell in 2009. He joined AFRL in 2009, initially as a contractor for Solid State Scientific Corp. and shortly after as a DR-II Electronics Engineer civilian in the Antenna Technology Branch (RYHA) at Hanscom Air Force Base. He was assigned to RYDP in 2011 at Wright-Patterson Air Force Base. His research interests include plasmonics, metamaterials, nonlinear materials, gradient index media, detector enhancement, super-resolution imaging, compressive sensing, optical protection, and on-chip optical communication and processing. Dr. Limberopoulos is a member of the IEEE, American Physical Society, Sigma Xi, and AOC.

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IEEE Southeastern Michigan