Perfect imaging of hypersurfaces via transformation optics

Klaus Mantel, Dustin Bachstein, Ulf Peschel

Conventional optical imaging systems suffer from the presence of many imperfections, such as spherical aberrations, astigmatism, or coma. If the imaging system is corrected for spherical aberrations and fulfills the Abbe sine condition, perfect imaging is guaranteed between two parallel planes but only in a small neighborhood of the optical axis. It is therefore worth asking for optical systems that would allow for perfect imaging between arbitrary smooth surfaces without restrictions in shape or extension. In this Letter, we describe the application of transformation optics to design refractive index distributions that allow perfect, aberration-free imaging for various imaging configurations in R(n). A special case is the imaging between two extended parallel lines in R(2), which leads to the well-known hyperbolic secant index distribution that is used for the fabrication of gradient index lenses. (C) 2011 Optical Society of America

Experimental Comparison of All-Optical Phase-Preserving Amplitude Regeneration Techniques

Daniel Endres, Christian Stephan, Klaus Sponsel, Georgy Onishchukov, Bernhard Schmauss, Gerd Leuchs

Performance of a nonlinear amplifying loop mirror and a fiber optical parametric amplifier in saturation used as phase-preserving amplitude limiters was investigated in a setup simulating a DPSK transmission system. The Q-factor improvement as well as the power penalty reduction have been compared under identical conditions. Both regenerators provide a similar Q-factor improvement, but the nonlinear amplifying loop mirror yields a better power penalty reduction.

Realistic g((2)) measurement of a PDC source with single photon detectors in the presence of background

Andreas Eckstein, Andreas Christ, Peter J. Mosley, Christine Silberhorn

The g(2) correlation function of a light beam depends on its photon statistcs. In quantum optics, this effect can be used to determine the effective mode number of a type II parametric downconversion source. However, the outcome is very sensitive against background light from other sources. We consider the experimental challenges of this approach and introduce a simple model to account for influence of the background. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Quadrant detector calibration for vortex beams

N. Hermosa, A. Aiello, J. P. Woerdman

This Letter reports an experimental and theoretical study of the response of a quadrant detector (QD) to an incident vortex beam, specifically a Laguerre-Gaussian (LG) beam. We have found that the LG beam response depends on the vorticity index l. We compare LG beams with hard-ringed beams and find that at higher l values, the QD response to LG beams can be approximated by its response to hard-ringed beams. Our findings are important in view of the increasing interest in optical vortex beams. (C) 2011 Optical Society of America

Nanoparticle-based protein detection by optical shift of a resonant microcavity

Miguel A. Santiago-Cordoba, Svetlana V. Boriskina, Frank Vollmer, Melik C. Demirel

We demonstrated a biosensing approach which, for the first time, combines the high sensitivity of whispering gallery modes (WGMs) with a metallic nanoparticle-based assay. We provided a computational model based on generalized Mie theory to explain the higher sensitivity of protein detection. We quantitatively analyzed the binding of a model protein (i.e., Bovine Serum Albumin) to gold nanoparticles from high-Q WGM resonance frequency shifts, and fit the results to an adsorption isotherm, which agrees with the theoretical predictions of a two-component adsorption model. (C) 2011 American Institute of Physics. [doi:10.1063/1.3599706]

Coupled-mode theory for on-channel nonlinear microcavities

Victor Grigoriev, Fabio Biancalana

We consider a nonlinear microcavity separating a waveguide channel into two parts so that the coupling between them is possible only due to the resonant properties of the microcavity. We provide a rigorous derivation of the equations used in the phenomenological coupled-mode theory for such systems. This allows us to find the explicit formulas for all fitting parameters such as decay rates, coupling coefficients, and characteristic intensities in terms of the mode profiles. The advantages of using the semianalytical approach are discussed, and the accuracy of the results is compared with strictly numerical methods. Particular attention is paid to multilayered structures since they represent the simplest realization of on-channel microcavities. (C) 2011 Optical Society of America

Spectral overlap in direct measurements of displaced single-photon states

K. Laiho, M. Avenhaus, K. N. Cassemiro, C. Silberhorn

Many sophisticated quantum states of light display non-classical, characteristic oscillations in their photon statistics altering with respect to the applied displacement. In order to detect these oscillations the mode matching between the studied state and the displacement field plays a crucial role. Only recently the developments in the photon counting techniques have allowed the direct measurements of the photon-number distributions of quantum states. We investigate the properties of displaced single photons by applying time-multiplexed detection of photon statistics and quantify the value of the mode overlap.

Dynamics of coupled multimode and hybrid optomechanical systems

Georg Heinrich, Max Ludwig, Huaizhi Wu, K. Hammerer, Florian Marquardt

Recent experimental developments have brought into focus optomechanical systems containing multiple optical and mechanical modes interacting with each other. Examples include a setup with a movable membrane between two end-mirrors and "optomechanical crystal" devices that support localized optical and mechanical modes in a photonic crystal type structure. We discuss how mechanical driving of such structures results in coherent photon transfer between optical modes, and how the physics of Landau-Zener-Stueckelberg oscillations arises in this context. Another area where multiple modes are involved are hybrid systems. There, we review the recent proposal of a single atom whose mechanical motion is coupled to a membrane via the light field. This is a special case of the general principle of cavity-mediated mechanical coupling. Such a setup would allow the well-developed tools of atomic physics to be employed to access the quantum state of the 'macroscopic' mechanical mode of the membrane. (C) 2011 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Frustrated quantum phase diffusion and increased coherence of solitons due to nonlocality

Sascha Batz, Ulf Peschel

We investigate the quantum properties of solitons with nonlocal self-interaction. We find significant changes when compared to the local interaction. Quantum phase diffusion of nonlocal solitons is always reduced with respect to the local interaction and vanishes in the strongly nonlocal limit. Thus, coherence is increased in the nonlocal case. Furthermore, we compare the intrinsic quantum wave packet spreading to the recently discussed classical Gordon-Haus effect for nonlocal solitons [V. Folli and C. Conti, Phys. Rev. Lett. 104, 193901 (2010)].

Concentrating the phase of a coherent state by means of probabilistic amplification

Mario A. Usuga, Christian R. Mueller, Christoffer Wittmann, Petr Marek, Radim Filip, Christoph Marquardt, Gerd Leuchs, Ulrik L. Andersen

We discuss the recent implementation of phase concentration of an optical coherent state by use of a probabilistic noiseless amplifier. The operation of the amplifier is described pictorially with phase space diagrams, and the experimental results are outlined.