Surface plasmons are elementary excitations in metallic nanoparticles that can localize the electromagnetic field on the nanoscale, creating highly concentrated and resonantly enhanced local electric optical fields. Our goal is to take advantage of this enhancement by locating a quantum emitter, which can be an individual molecule or a semiconductor quantum dot, at a close proximity to a metallic nanoparticle.
The behavior of electrons in semiconductor quantum wells subjected to a high magnetic field is governed by their mutual interactions. The fractional quantum Hall effect is probably the most dramatic manifestation of these interactions: The Hall resistance is precisely quantized at h/e2 divided by either an integer or a simple fraction. More than 70 fractions have so far been observed.
The understanding of this phenomenon is at the focus of experimental and theoretical research at the past three decades. The research at our group makes use of various optical spectroscopy techniques, such as photoluminescence, absorption, photoluminescence excitation (PLE), photocurrent, and resistively detected NMR, to study various issues related to the behavior of the electron gas in this regime, and in particular, the electrons spin polarization at various fractions.
The study of excitons in semiconductors has been an active field of research for many years. Their signature, which dominates the near-bandgape optical properties of semiconductor heterostructures, can be manipulated via external fields or through engineering of the crystal structure, giving rise to a wealth of physical phenomena. Their equivalence with hydrogen atoms was found to hold beyond the single neutral atom.
Theory predicts that at densities, which are well above the Mott transition, the exciton system may form a liquid. At very low temperature and densities one expects to form a Bose condensate, while at higher temperatures and densities – a classical liquid. Our goal is to observe these correlated states in coupled quantum wells structures.