Summer 2007 article selection
As member of the OMNT “materials and components for optics” committee, I regularly give a selection and a brief description of articles, that I found particularly relevant to the field. Here is my latest selection :
"Generation of optical Schrödinger cats from photon number states"; Alexei Ourjoumtsev, Hyunseok Jeong, Rosa Tualle-Brouri et Philippe Grangier, Nature 448, 784-786 (2007).
Schrodinger’s cat is a Gedankenexperiment in quantum physics, in which an atomic decay triggers the death of the cat. Because quantum physics allow atoms to remain in superpositions of states, the classical cat would then be simultaneously dead and alive. By analogy, a ‘cat’ state of freely propagating light can be defined as a quantum superposition of well separated quasiclassical states—it is a classical light wave that simultaneously possesses two opposite phases. Such states play an important role in fundamental tests of quantum theory and in many quantum information processing tasks, including quantum computation, quantum teleportation and precision measurements. Recently, optical Schrodinger ‘kittens’ were prepared; however, they are too small for most of the aforementioned applications and increasing their size is experimentally challenging. Here we demonstrate, theoretically and experimentally, a protocol that allows the generation of arbitrarily large squeezed Schrodinger cat states, using homodyne detection and photon number states as resources. We implemented this protocol with light pulses containing two photons, producing a squeezed Schro¨dinger cat state with a negative Wigner function. This state clearly exhibits several quantum phase-space interference fringes between the ‘dead’ and ‘alive’ components, and is large enough to become useful for quantum information processing and experimental tests of quantum theory.
"Label-free single molecule detection with optical microcavities"; A. A. Armani, R. P. Kulkarni, S.E. Fraser, R. C. Flagan et K. J. Vahala, Science 317, 783-787 (2007).
"Electromigrated nanoscale gaps for surface enhanced Raman spectroscopy"; D.R. Ward, N.K. Grady, C.S. Levin, N.J. Halas, Y. Wu, P. Nordlander et D. Nathelson, Nano Letters 7, 1396-1400 (2007).