Bulletin of the American Physical Society
39th Annual Meeting of the APS Division of Atomic, Molecular, and Optical Physics
Volume 53, Number 7
Tuesday–Saturday, May 27–31, 2008; State College, Pennsylvania
Session B5: Quantum and Nonlinear Optics |
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Chair: Susanne Yelin, University of Connecticut Room: Nittany Lion Inn Boardroom I |
Wednesday, May 28, 2008 11:00AM - 11:12AM |
B5.00001: Strong Interaction Between Light and a Single Trapped Atom Without a Cavity Meng Khoon Tey, Zilong Chen, Syed Aljunid, Brenda Chng, Gleb Maslennikov, Christian Kurtsiefer We measured the extinction of a focused light beam by a single 87Rb atom localized in an optical dipole trap and found a value of 9.7\% for a focused Gaussian beam resonantly interacting with an atomic two-level system. Various models describing interaction of an atom with a focused light field are compared to explain our experimental result. Our experiment suggests that a strong coupling may be achieved without cavity assistance. This opens new perspectives for an efficient quantum state transfer of a photonic qubit into an atom. Furthermore, the strong effecitive nonlinerity of the atom may be used to efficiently implement a phase gate between two photons. [Preview Abstract] |
Wednesday, May 28, 2008 11:12AM - 11:24AM |
B5.00002: Optical switching via recoil-induced resonances Joel Greenberg, Marcos Oria, Daniel Gauthier Recoil-induced resonances (RIRs), which can be viewed as Raman transitions between momentum states, result in very narrow (~100 kHz) Gaussian-derivative lineshapes. While the amplitude of these signals has traditionally been small, quasi-one dimensional samples of cold atoms obtained via an anisotropic magneto-optical trap (MOT) have been used to demonstrate large steady-state gains. Along with these large gains, the index of refraction changes rapidly over a narrow frequency range, allowing for sensitive control of the phase shift induced by the atoms. This, combined with the intensity-dependence of the observed gain, enables optical switching with low input powers. We report our progress on achieving an all-optical phase switch in a sub-Doppler collection of Rb atoms contained in an anisotropic MOT. [Preview Abstract] |
Wednesday, May 28, 2008 11:24AM - 11:36AM |
B5.00003: Low-frequency vacuum squeezing in Rb vapor Eugeniy Mikhailov, Irina Novikova Reduction of noise in the optical field below the quantum noise limit is called squeezing. We study generation of squeezed vacuum at 795nm central wavelength in Rb vapor via resonant polarization self-rotation of the pump field, and report noise sidebands suppression of $\sim $1 dB below shot noise level spanning from acoustic (tens of kHz) to MHz frequencies. The spectral range of observed squeezing matches well typical bandwidths of electromagnetically induced transparency (EIT) resonances. Thus, this simple technique for generation of optical fields with non-classical statistics at atomic transitions wavelengths is attractive for EIT-based quantum information protocols applications. [Preview Abstract] |
Wednesday, May 28, 2008 11:36AM - 11:48AM |
B5.00004: EIT with noisy laser fields Yanhong Xiao, Tun Wang, Susanne F. Yelin, Maria Baryakhtar, David F. Phillips, Ronald L. Walsworth We have investigated noise processes in Electromagnetically Induced Transparency (EIT). We identify a resonance resistant to power broadening and a novel form of EIT manifested by dips in intensity noise spectra, caused by reduced conversion of phase noise to intensity noise. An intuitive explanation in good agreement with numerical calculations and experimental results will be presented. These results have applications in spectroscopy, atomic clocks and magnetometers. [Preview Abstract] |
Wednesday, May 28, 2008 11:48AM - 12:00PM |
B5.00005: Non-linear Optics with Cold Atoms inside a Hollow Core Photonic Crystal Fiber Michal Bajcsy, Sebastian Hofferberth, Vlatko Balic, Thibault Peyronel, Alexander Zibrov, Vladan Vuletic, Mikhail Lukin The confinement of cold atoms and photons to a diameter comparable to optical wavelength inside a hollow core photonic crystal fiber dramatically enhances the probability of interaction between a single photon and a single atom compared to free space. As a result, an atomic ensemble consisting of a relatively small number of atoms will create a high optical depth medium that will only need a small number of photons to saturate. Furthermore, coherent control techniques such as Electromagnetically Induced Transparency (EIT) can be used to manipulate atom-photon interactions. Here we present an experimental realization of a few-photon switch based on such a system. [Preview Abstract] |
Wednesday, May 28, 2008 12:00PM - 12:12PM |
B5.00006: Controlled generation of Rb-vapor in hollow-core photonic bandgap fibers Amar Bhagwat, Aaron Slepkov, Vivek Venkataraman, Pablo Londero, Alexander Gaeta Hollow-core photonic bandgap fibers (HC-PBGF) offer a unique geometry for performing strong nonlinear interactions with atomic vapors at very low light powers over long interaction lengths. The difficulties associated with generating, accessing, and maintaining stable atomic vapors within HC-PBGF remain the main challenges to such experiments. By chemically modifying the inner core walls of these fibers, we use light-induced atomic desorption to liberate surface-adsorbed Rb atoms. We perform time-resolved studies of atomic desorption dynamics to map out the characteristic timescales associated with the process. We find that by appropriately controlling the power and duration of the desorption beam we obtain metastable, optically-dense, and repeatable densities of Rb without appreciably depleting the fiber, and we demonstrate the use of this vapor for quantum optical applications at nanowatt optical powers. [Preview Abstract] |
Wednesday, May 28, 2008 12:12PM - 12:24PM |
B5.00007: Observation of Optical Precursors at the Biphoton Level Shengwang Du, Chinmay Belthangady, Pavel Kolchin, G.Y. Yin, S.E. Harris We report the first observation of optical precursors at the front edge of a biphoton wave packet, as measured by correlation of single photons. Optical precursors were first described by Sommerfeld and Brillouin in 1907, and are of importance in electromagnetic theory in that they resolve theoretical difficulties when group velocities are slow or fast as compared to c in vacuum. Here, we describe the quantum optical precursors in time-energy entangled biphoton wave packets generated using EIT in a two-dimensional 85Rb magneto-optical trap. The frequency components within the EIT window contribute to the biphoton main waveform as determined by the slow group velocity. The transient structure at the leading edge of the biphoton wave packet is a result of interference between two far-detuned frequency bands. This interference gives rise to the generation of a precursor field with a steep rising leading edge (Sommerfeld) followed by damped oscillations (Brillouin). A stationary phase approximation agrees well with the experimental results at optical depths between 30 and 62. [Preview Abstract] |
Wednesday, May 28, 2008 12:24PM - 12:36PM |
B5.00008: STIRAP in a sodium gas using picosecond lasers Kevin Lyon, Susan D. Allen, Michael J. Johnson, William D. Murry, Daniel R. Britton, Tomasz Kutner, J. Bruce Johnson We demonstrate for the first time with picosecond lasers, the STIRAP technique on sodium vapor with a ladder scheme using the 3p ($^{2}$P$_{1/2}) \quad \leftarrow $ 3s ($^{2}$S$_{1/2})$ and 5s ($^{2}$S$_{1/2}) \quad \leftarrow $ 3p ($^{2}$P$_{1/2})$ transitions. Light to couple the states was produced by two synchronously pumped OPGs and further amplified in two OPAs (pumped by the 355 nm light from a picosecond YAG). Fluorescence from the 5s state to both 3p states ($^{2}$P$_{1/2}$, $^{2}$P$_{3/2})$ and from both 3p states to the 3s state was measured with a monochromator using a gated CCD to eliminate Rayleigh scattered light. Our results indicate a five-fold increase in the transfer efficiency to the 5s state when the laser pulse that couples the 3p and 5s states temporally precedes the laser pulse tuned to the 3p $\leftarrow $ 3s transition. [Preview Abstract] |
Wednesday, May 28, 2008 12:36PM - 12:48PM |
B5.00009: Simultaneously spectral phase and amplitude characterization of coherent molecular vibrations and its application in Coherent Anti-Stokes Raman Spectroscopy Xiaoji Xu, Stanislav Konorov, John Hepburn, Valery Milner The authors propose a new approach to vibration spectroscopy based on the coherent scattering of broadband ultrashort laser pulses. The proposed method reveals both the amplitude and the phase of molecular vibrations by utilizing cross-correlation Frequency Resolved Optical Gating technique (XFROG) in Coherent anti-Stokes Raman Scattering (CARS). The spectrum is measured as a function of the time delay between the laser-induced molecular vibrations and a well characterized broadband probe pulse. The iterative XFROG algorithm provides simultaneous complete characterization of molecular vibrations both in frequency and time domains with resolution better than pulse bandwidth or duration respectively. They experimentally demonstrate the feasibility of the proposed method and two of its potential applications: disentangling the time behavior of mixture of vibrationally excited molecules and CARS spectroscopy under high non-resonant background. Pulse shaping technique is used for further improvement of accuracy and stability against noise. [Preview Abstract] |
Wednesday, May 28, 2008 12:48PM - 1:00PM |
B5.00010: Classification of Four Three-Level Atomic Systems into Two Categories in Light of the Study of Their Resonances Tony Abi-Salloum Of the four possible three-level atomic systems (Lambda, Vee and two Cascade schemes), only two exhibit reduction in the absorption of a probe field when a weak second driving field is present. The reduction in absorption can be a result of Electromagnetically Induced Transparency (EIT) or it can be a consequence of Autler-Townes (AT) splitting. In this talk, we present studies of resonances of four different three-level systems. Two categories of three-level systems are compared and the line of separation between EIT and AT is delineated. [Preview Abstract] |
Wednesday, May 28, 2008 1:00PM - 1:12PM |
B5.00011: Four-wave mixing in a birefringent semiconductor waveguide for correlated photon generation Daniel Rogers, Julius Goldhar, Christopher Richardson, Alessandro Restelli, Joshua Bienfang, Charles Clark The next generation of optical devices for everything from communications to metrology will depend on a fast and practical source of entangled photon pairs. Current methods of entanglement, whether in bulk nonlinear crystals or microstructure optical fibers, pose significant challenges to integration into larger optical systems. In order to meet the demands for speed and practicality, we investigate third-order nonlinearity in a semiconductor waveguide as a source of correlated and ultimately entangled photon pairs. The source is potentially useful for free-space and fiber-optic quantum key distribution as well as a host of other applications such as correlated photon metrology and two-photon interferometry. Analysis of the effectiveness of birefringent phase matching will also provide some measure of the anisotropy of the third-order nonlinear response in III-V compound semiconductors, a significant unknown in nonlinear optics. We show the feasibility of using phase-matched four-wave mixing in a birefringent AlGaAs waveguide to generate correlated photon pairs at wavelengths compatible with silicon detectors. [Preview Abstract] |
Wednesday, May 28, 2008 1:12PM - 1:24PM |
B5.00012: Electromagnetic radiation by gravitating bodies Iwo Bialynicki-Birula, Zofia Bialynicka-Birula Gravitational radiation is now a well understood and observationally confirmed phenomenon. Gravitating bodies in motion, however, regardless of their constitution, always produce also electromagnetic radiation in the form of photon pairs. This phenomenon is an analog of the electromagnetic radiation caused by the motion of dielectric (or magnetic) bodies. This electromagnetic mechanism has its source in the variation of the material coefficients with time. In curved space the components of the metric tensor play the role of the material coefficients. The gravitational particle production is due to changes of the metric with time. This effect has been considered mostly in the cosmological context. In contrast, we consider here only local perturbations of the metric avoiding the global cosmological issues. Production of photon pairs caused by changes of the medium with time is a purely quantum-mechanical effect. One may say that the motion of the medium squeezes the electromagnetic vacuum. Unfortunately, the emitted radiation is extremely weak as compared to radiation produced by other mechanisms. [Preview Abstract] |
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