physics

Subcellular surgery and nanosurgery, at Engineering Spring Faculty Dinner, Johns Hopkins University (Elkridge, MD), Wednesday, March 22, 2017:
We use femtosecond laser pulses to manipulate sub-cellular structures inside live and fixed cells. Using only a few nanojoules of laser pulse energy, we are able to selectively disrupt individual mitochondria in live bovine capillary epithelial cells, and cleave single actin fibers in the cell cytoskeleton network of fixed human fibro-blast cells. We have also used the technique to micromanipulate the neural network of C. Elegans, a small nematode. Our laser scalpel can snip individual axons without causing any damage to surrounding tissue, allowing us to study the function of individual... Read more about Subcellular surgery and nanosurgery
Laser doping and texturing of silicon for advanced optoelectronic devices, at Frontiers in Optics (FiO)/Laser Science (LS) Conference (Rochester, NY), Monday, October 17, 2016:
Irradiating a semiconductor sample with intense laser pulses in the presence of dopants drastically changes the optical, material, and electronic properties of the sample. The resulting material has applications for photodetectors and, potentially, intermediate-band solar cells.
Less is More: Extreme Optics with Zero Refractive Index, at International Conference on Nanojoining and Microjoining 2016 (Niagara, ON, Canada), Sunday, September 25, 2016:
Nanotechnology has enabled the development of nanostructured composite materials (metamaterials) with exotic optical properties not found in nature. In the most extreme case, we can create materials which support light waves that propagate with infinite phase velocity, corresponding to a refractive index of zero. This zero index can only be achieved by simultaneously controlling the electric and magnetic resonances of the nanostructure. We present an in-plane metamaterial design consisting of silicon pillar arrays, embedded within a polymer matrix and sandwiched between gold layers. Using an... Read more about Less is More: Extreme Optics with Zero Refractive Index
Less is More: Extreme Optics with Zero Refractive Index, at National University of Singapore (Singapore), Wednesday, August 24, 2016:
Nanotechnology has enabled the development of nanostructured composite materials (metamaterials) with exotic optical properties not found in nature. In the most extreme case, we can create materials which support light waves that propagate with infinite phase velocity, corresponding to a refractive index of zero. This zero index can only be achieved by simultaneously controlling the electric and magnetic resonances of the nanostructure. We present an in-plane metamaterial design consisting of silicon pillar arrays, embedded within a polymer matrix and sandwiched between gold layers. Using an... Read more about Less is More: Extreme Optics with Zero Refractive Index
Breakthroughs in nanophotonics, at Nanyang Technological University (Singapore), Wednesday, August 24, 2016:
Nanotechnology has enabled the development of nanostructured composite materials (metamaterials) with exotic optical properties not found in nature. In the most extreme case, we can create materials which support light waves that propagate with infinite phase velocity, corresponding to a refractive index of zero. This zero index can only be achieved by simultaneously controlling the electric and magnetic resonances of the nanostructure. We present an in-plane metamaterial design consisting of silicon pillar arrays, embedded within a polymer matrix and sandwiched between gold layers. Using an... Read more about Breakthroughs in nanophotonics
Laser doping and texturing of silicon for advanced optoelectronic devices, at Tsing Hua University (Hsinchu, Taiwan), Wednesday, June 29, 2016:
Irradiating a semiconductor sample with intense laser pulses in the presence of dopants drastically changes the optical, material and electronic properties of the sample. The properties of these processed semiconductors make them useful for photodetectors and, potentially, intermediate band solar cells. This talk discusses the processes that lead to doping and surface texturing, which both increase the optical absorption of the material. We will discuss the properties of the resulting material including the formation of an intermediate band. We have developed laser-processed silicon... Read more about Laser doping and texturing of silicon for advanced optoelectronic devices
Phase-Matching in Dirac-Cone-Based Zero-Index Metamaterials, at CLEO: Science and Innovations (San Jose, CA), Sunday, June 5, 2016:
Using nonlinear scattering theory, we simulate nonlinear signal generation in 2-dimensional zero-index metamaterials based on a photonic Dirac cone at the G point. We observe unique phase-matching in multiple simultaneous directions as the index approaches zero.
Non-equilibrium materials by fs-laser texturing and hyperdoping of silicon, at AFOSR Ultrashort Pulse Laser-Matter Interactions PI Review (Arlington, VA), Thursday, June 2, 2016:
Ultrafast-laser hyperdoped semiconductors have begun to be utilized for optoelectronic applications, but there is a need to better understand their fundamental physical properties. In this presentation, we discuss recent work on the basic science of ultrafast-laser structuring, time-resolved melting, resolidification, and hyperdoping, and the optical and electronic properties hyperdoped silicon. These aspects of ultrafast-laser hyperdoped semiconductors are central to hyperdoped materials science and device design.
Less is More: Extreme Optics with Zero Refractive Index, at 8th International Symposium on Advanced Optical Manufacturing and Testing Technologies ( AOMATT 2016) (Suzhou, China), Tuesday, April 26, 2016:
Nanotechnology has enabled the development of nanostructured composite materials (metamaterials) with exotic optical properties not found in nature. In the most extreme case, we can create materials which support light waves that propagate with infinite phase velocity, corresponding to a refractive index of zero. This zero index can only be achieved by simultaneously controlling the electric and magnetic resonances of the nanostructure. We present an in-plane metamaterial design consisting of silicon pillar arrays, embedded within a polymer matrix and sandwiched between gold layers. Using an... Read more about Less is More: Extreme Optics with Zero Refractive Index

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