Ph.D., University of Rochester, 1982.

Assistant Professor to Professor, University of Arkansas, 1982-92.

Chair of the Department 1995 - 2002, 2005-to date.

Fellow, American Physical Society, 2003

Visiting Fellow, Joint Institute for Laboratory Astrophysics (JILA), University of Colorado, 1989-90.

Professor Singh joined the University of Arkansas in 1982, after completing his dissertation under Professor Leonard Mandel. Although primarily an experimentalist, he is equally apt at theory. He has done extensive work on quantum and classical noise in lasers, and nonlinear and quantum optics. In addition to continuing his research in these areas he is exploring applications of optics to the study of nanoparticles and biopolymers.

QUANTUM OPTICS AND OPTICS OF NANOPARTICLES AND BIOPOLYMERS

The fundamental question in the field of optics is the nature of light itself. Studies of light and its interaction with matter keep generating new ideas and inventions unraveling the nature of light and leading to new applications of light. In this sense optics seems to have found the secret of eternal youth. We are interested in both classical and quantum features of light in interacting light-matter systems. These include lasers, nonlinear optical processes such as second harmonic generation and frequency down-conversion and simple atomic systems interacting with a small number of modes inside or outside an optical cavity.

Our current interests can be classified into three broad areas. The first involves studies of statistical properties of light by means of photoelectric counting and correlation techniques. Our current interest is focused on nonclassical features of light as such as photon anti-bunching, nonclassical photon correlations, squeezing, and entanglement in optical parametric oscillators. These investigations explore the boundary between classical and quantum descriptions of light and their results can only be understood quantum mechanically. We are also interested in developing new techniques for characterizing and measuring quantum features of light. For example, a photodetection techniques based on two-photon absorption of light, has allowed us go beyond conventional techniques to explore certain higher order photon correlations of light from a laser near threshold and micro-cavity semiconductor laser.

The second area of interest involves studies of nonlinear dynamics and its role in shaping the temporal fluctuations of light. These studies are being carried out in two-mode ring lasers with modulated gain or loss. Current experimental efforts are focused on optically pumped solid-state Ti-sapphire and YAG rings lasers. Such systems are capable of exhibiting an extremely rich array of dynamical behavior including transitions between multiple steady states, oscillatory states and even chaotic states, depending on the depth and frequency of modulation and the number of modes in the laser. Especially exciting is the possibility that under certain conditions chaotic dynamics of modes may be synchronized. These studies of nonlinear dynamics may find applications in laser pulse crafting and secure optical communication.

The third area of interest is application of optics to the study of nanoparticles and biopolymers. Several such projects are underway including optical tweezers based on higher Hermite-Gauss and Laguerre-Gauss laser beams for manipulating biomolecules and nanoparticles, light scattering studies of nano-particles and evanescent wave detection of biomolecules and nanoparticles.

A variety of experimental techniques relying on fast photon counting and correlation equipment are in use. Nonlinear crystals, carefully designed optical cavities, He:Ne, semiconductor, Ar-ion, and optically pumped Ti-Sapphire and YAG lasers, transient digitizers, a host of other electronic instruments, and personal computers are available for these experiments.