Ultra-short light pulses

Intensive light pulses with durations of between some 10⁻¹² and 10⁻¹⁴ seconds have recently become available. With these ultra-short light pulses experiments can now be carried out that were thought impossible only a few years ago. Examples from molecular physics, semiconductor physics, biophysics, and chemistry illustrate the wide range of opportunities and new information to be gained from this considerable enhancement of the experimental timescale.     

Modeling with light

The problem of making solid objects appear as they are—three-dimensional—is largely a matter of lighting. The subject occurs in the education of children, in the illumination of statuary, in photography, and in television; and the treatment has been almost entirely qualitative and empirical.This paper attempts to raise the problem to the quantitative level by introducing a numerical modeling ratio and by showing how the lighting can be predetermined by calculation to give any desired modeling, without recourse to the cut-and-try methods prevalent in the past.     

Topological phases of quantized light

Topological photonics is an emerging research area that focuses on the topological states of classical light. Here we reveal the topological phases that are intrinsic to the quantum nature of light, i.e. solely related to the quantized Fock states and the inhomogeneous coupling strengths between them. The Hamiltonian of two cavities coupled with a two-level atom is an intrinsic one-dimensional Su-Schriefer-Heeger model of Fock states. By adding another cavity, the Fock-state lattice is extended to two dimensions with a honeycomb structure, where the strain due to the inhomogeneous coupling strengths of the annihilation operator induces a Lifshitz topological phase transition between a semimetal and three band insulators within the lattice. In the semimetallic phase, the strain is equivalent to a pseudomagnetic field, which results in the quantization of the Landau levels and the valley Hall effect. We further construct an inhomogeneous Fock-state Haldane model where the topological phases can be characterized by the topological markers. With d cavities being coupled to the atom, the lattice is extended to d − 1 dimensions without an upper limit. In this study we demonstrate a fundamental distinction between the topological phases in quantum and classical optics and provide a novel platform for studying topological physics in dimensions higher than three.