Hyperbolic Polaritons

In 1987, the search for a medium that expels vacuum fluctuations in a prescribed bandwidth and rigorously forbids spontaneous emission led to the concept of the photonic crystal. Here, we argue that the search for the opposite effect: enhancing vacuum and thermal fluctuations inside a medium within a prescribed bandwidth can be accomplished by an artificial medium known as a hyperbolic metamaterial.

From fundamental reaction mechanisms to improved heterogeneous catalysts

First-principles calculations for heterogeneously catalysed reactions have emerged as a major source of information for understanding the underlying reaction mechanism. Combining computational chemistry derived insights with experimentally measured reaction rates and reaction orders, along with input from spectroscopies and materials characterization techniques can lead the quest for the nature of the active site.

Generation and applications of nonlinear-dispersive similaritons in fibers

Similaritons, pulses with the distinctive property of self-similar propagation, are attractive due to their fundamental interest and prospective applications in ultrafast optics and photonics. The signal analysis and synthesis problems on the femtosecond time scale demand the generation of broadband similaritons.

Linear and non-linear Raman spectroscopy in the single molecule limit

Ara Apkarian, UC Irvine

Energetics of single-molecule interfaces

The study of single molecules delivers deep insights into bonding nature and underlying quantum mechanics concerning about controlling chemical reaction. The scanning tunneling microscope (STM) is a versatile and powerful tool for investigating and controlling chemistry of individual molecules on the solid surfaces. The coupling of tunneling electrons to the electronic and vibrational states of the target molecule allows us to realize mode-selective and state-selective chemistry of the individual molecules.

Atomic Manipulation and Force Spectroscopy on Cu(110)-O Surface with Low Temperature FM-AFM

Manipulation of single atoms and molecules is an innovative experimental technique of nanoscience. Recently, an atomic force microscopy (AFM) has been used to manipulate single atoms and molecules. Atom manipulation with an AFM is particularly promising, because it allows the direct measurement of the required forces.

Visualization of Hydrogen Bonding, Van der Waals Force, and the Control of Chemistry

The interrelationship among the structure, bonding, and reactivity of molecules lies at the foundation of our understanding and control of chemistry. A few examples are given to illustrate the use of the scanning tunneling microscope to follow the interactions between two molecules and to image the molecular skeletal structure, intra- and extramolecular bonding, and chemical fingerprinting of the reactants and products.

Multidimensional Photoelectron Spectroscopy of the Coherent Optical Response of Metals

We employ energy, momentum, and time resolved multi-photon photoemission spectroscopy to probe the coherent response of metals at optical frequencies. Although the reflection of light from a metal is considered to be an essentially instantaneous process, photoelectron spectra excited with tunable laser sources are able to select particular components of the response that are subject to long (>20 fs) dephasing times. Specifically, we examine the responses of Cu(111) and Ag(111) surfaces focusing on the three-photon photoemission from their Shockley surface states.

Combined second-harmonic generation and sum-frequency generation microscopy of collagen

The Spin on Electronics! Science and Technology of spin currents in nano-materials and nano-devices

Recent advances in manipulating spin-polarized electron currents in atomically engineered magnetic heterostructures make possible entirely new classes of sensor, memory and logic devices - a research field generally referred to as spintronics. A magnetic recording read head, initially formed from a spin-valve, and more recently by a magnetic tunnel junction, has enabled a 1,000-fold increase in the storage capacity of hard disk drives since 1997.

UCI Department of Chemistry

CaSTL