Bending light to our will

This article is based on the Fred Kavli Distinguished Lectureship in Nanoscience presentation given by Harry Atwater (California Institute of Technology) on April 5, 2010 at the Materials Research Society Spring Meeting in San Francisco, CA. The Kavli Foundation supports scientific research, honors scientific achievement, and promotes public understanding of scientists and their work. Its particular focuses are astrophysics, nanoscience, and neuroscience. Solar energy is currently enjoying substantial growth and investment, owing to worldwide sensitivity to energy security and climate change. Solar energy is an inexhaustible resource and is in abundant supply on all continents of the world. The power density of sunlight (~1000 W/m 2 ) and the effi ciency of photovoltaic devices (~10–25%) are high enough so that land use does not limit photovoltaic deployment at the terawatt scale. However solar photovoltaics are currently too expensive to achieve parity with other forms of electricity generation based on fossil fuels. This is largely due to the cost (and for some cases, the abundance) of materials used in photovoltaic modules and systems, and the cost of deploying in current form. This economic and social context has created the present situation where there is widespread interest in photovoltaic technology for power generation, but the cumulative installed world capacity for photovoltaics is <50 GW, and it appears to be very challenging for photovoltaics to play a very substantial role in large-scale (terawatt) electricity generation in the short term

Nonlinear optical interactions in silicon waveguides

The strong nonlinear response of silicon photonic nanowire waveguides allows for the integration of nonlinear optical functions on a chip. However, the detrimental nonlinear optical absorption in silicon at telecom wavelengths limits the efficiency of many such experiments. In this review, several approaches are proposed and demonstrated to overcome this fundamental issue. By using the proposed methods, we demonstrate amongst others supercontinuum generation, frequency comb generation, a parametric optical amplifier, and a parametric optical oscillator

Nonlinear optical effects in artificial materials

We consider some nonlinear phenomena in metamaterials with negative refractive index properties. Our consideration includes a survey of previously known results as well as identification of the phenomena that are important for applications of this new field. We focus on optical behavior of thin films as well as multi-wave interactions.Comment: 22 pages, no figures. Submitted in book "Nonlinear waves in complex systems: energy flow and geometry

Controlling phonons and photons at the wavelength-scale: silicon photonics meets silicon phononics

Radio-frequency communication systems have long used bulk- and surface-acoustic-wave devices supporting ultrasonic mechanical waves to manipulate and sense signals. These devices have greatly improved our ability to process microwaves by interfacing them to orders-of-magnitude slower and lower loss mechanical fields. In parallel, long-distance communications have been dominated by low-loss infrared optical photons. As electrical signal processing and transmission approaches physical limits imposed by energy dissipation, optical links are now being actively considered for mobile and cloud technologies. Thus there is a strong driver for wavelength-scale mechanical wave or "phononic" circuitry fabricated by scalable semiconductor processes. With the advent of these circuits, new micro- and nanostructures that combine electrical, optical and mechanical elements have emerged. In these devices, such as optomechanical waveguides and resonators, optical photons and gigahertz phonons are ideally matched to one another as both have wavelengths on the order of micrometers. The development of phononic circuits has thus emerged as a vibrant field of research pursued for optical signal processing and sensing applications as well as emerging quantum technologies. In this review, we discuss the key physics and figures of merit underpinning this field. We also summarize the state of the art in nanoscale electro- and optomechanical systems with a focus on scalable platforms such as silicon. Finally, we give perspectives on what these new systems may bring and what challenges they face in the coming years. In particular, we believe hybrid electro- and optomechanical devices incorporating highly coherent and compact mechanical elements on a chip have significant untapped potential for electro-optic modulation, quantum microwave-to-optical photon conversion, sensing and microwave signal processing.Comment: 26 pages, 5 figure