Bulletin of the American Physical Society
50th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics APS Meeting
Volume 64, Number 4
Monday–Friday, May 27–31, 2019; Milwaukee, Wisconsin
Session V06: Laser and nonlinear optics and spectroscopy |
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Chair: Elohim Becerra, University of New Mexico Room: Wisconsin Center 102DE |
Friday, May 31, 2019 8:00AM - 8:12AM |
V06.00001: Tunable Finesse and Beam Transformations with Coupled Cavities Mark Stone, Aziza Suleymanzade, Jonathan Simon I will describe several related tools for use in atomic physics experiments and general laser manipulation, which rely on techniques using coupled optical cavities. The first is a tunable finesse cavity whose coupling to free space can be changed by orders of magnitude, amounting to a variable photon lifetime. Then I will demonstrate that, with the correct configuration of coupled resonators, an input Hermite-Gaussian beam can have its spatial and frequency properties drastically altered with little loss of power. These tools are easily constructed and robust to high laser powers. [Preview Abstract] |
Friday, May 31, 2019 8:12AM - 8:24AM |
V06.00002: Large time-bandwidth photonic waveguide coupled light storage Wui Seng Leong, Mingjie Xin, Zilong Chen, Shau-Yu Lan Integrating light storage or optical delay line in an optical fibre is an attractive component in connecting long distance optical communication networks. Although silica-core optical fibres are excellent in transmitting broadband optical signals, it is challenging to tailor its dispersive property for long light storage time. Coupling tunable dispersive medium with an optical fibre is promising in supporting high performance optical delay line memory while transmitting the light with small loss. Here, we load cold Rb atomic vapour in an optical trap inside a hollow-core fibre and demonstrate light storage using electromagnetically-induced-transparency (EIT). We achieve over 20 ms of the storage time with 1 MHz bandwidth of the pulse. The storage time-bandwidth product exceeds $10^4$. Our long memory built-in optical fibre could be used for buffering and regulating classical and quantum information flow between remote networks. [Preview Abstract] |
Friday, May 31, 2019 8:24AM - 8:36AM |
V06.00003: Conical Intersections Induced by Quantum Light: Field-Dressed Spectra from the Weak to the Ultrastrong Coupling Regimes. Agnes Vibok, Tamas Szidarovszky, Attila G. Csaszar, Lorenz S. Cederbaum, Gabor J. Halasz In classical laser fields with frequencies resonant with the electronic excitation in molecules, it is by now known that conical intersections are induced by the field and are called light-induced conical intersections (LICIs). As optical cavities have become accessible, the question arises whether their quantized modes could also lead to the appearance of LICIs. A theoretical framework is formulated for the investigation of LICIs of diatomics in such quantum light. The eigenvalue spectrum of the dressed states in the cavity is studied, putting particular emphasis on the investigation of absorption spectra of the Na$_{\mathrm{2}}$ molecule, that is, on the transitions between dressed states, measured by employing a weak probe pulse. The dependence of the spectra on the light-matter coupling strength in the cavity and on the frequency of the cavity mode is studied in detail. The computations demonstrate strong nonadiabatic effects caused by the appearing LICI. [Preview Abstract] |
Friday, May 31, 2019 8:36AM - 8:48AM |
V06.00004: Reduced-Density-Matrix Description of Decoherence and Relaxation Processes Pertaining to Electron-Spin Systems Verne Jacobs Electron-spin systems are investigated using a quantum-open-systems description. Applications of interest include trapped atomic systems in optical lattices, semiconductor quantum dots, and vacancy defect centers in solids. Time-domain and frequency-domain formulations are developed. The general non-perturbative and non-Markovian formulations can provide a fundamental framework for systematic investigations of corrections to the standard Born and Markov approximations. Attention is given to decoherence and relaxation processes, as well as spectral-line broadening phenomena, that are induced as a result of interactions with photons, phonons, nuclear spins, and external electric and magnetic fields. These dissipative phenomena can be described either as coherent interactions or as environmental interactions. The environmental interactions are incorporated by means of the general expressions derived for the time-domain and frequency-domain Liouville-space self-energy operators, for which the tetradic-matrix elements are explicitly evaluated in the diagonal-resolvent, lowest-order, and Markov (short-memory time) approximations. Work supported by the Office of Naval Research through the Basic Research Program at The Naval Research Laboratory. [Preview Abstract] |
Friday, May 31, 2019 8:48AM - 9:00AM |
V06.00005: Spatiotemporal profile of yoked superfluorescence from Rb vapor Kenta Kitano, Haruka Maeda Yoked superfluorescence (YSF) is a nonlinear optical phenomenon, which appears when a three level system is initially prepared in a superposition between the ground and the excited states. When the superfluorescence (SF) emission occurs between the excited and the intermediate states within the system decoherence time, it is accompanied by a simultaneous emission of a coherent pulse resulting from the transition from the intermediate to the ground states. The interplay between the two emissions is called YSF, which is considered as a time-delayed four-wave mixing process. We investigated the YSF of rubidium atoms by driving the 5S-5D two-photon transition with an ultrashort laser pulse. By increasing the pump-pulse power beyond the saturation intensity, the spatial profile of the YSF pulse resulting from the 6P-5S transition periodically changed between a central bright spot and a ring-shaped radial profile. The experimental results were successfully reproduced by simulations using the Maxwell-Bloch equations, indicating that a single-atom Rabi oscillation during the pump-pulse excitation is responsible for the spatial beam profile of the YSF pulse. [Preview Abstract] |
(Author Not Attending)
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V06.00006: Probing, quantifying, and freezing coherence in room temperature atoms Arif Warsi Laskar, Niharika Singh, Pratik Adhikary, Arunabh Mukherjee, Saikat Ghosh Stable superposition of quantum states is the building block of quantum technologies and protocols, and the ability to generate and control such states provide distinct advantages when compared to their corresponding classical counterpart. Accordingly, there has been a major research thrust in distilling and quantifying such coherence in recent years. A widely used technology to generate such stable superposition in atom-like system is electromagnetically induced transparency (EIT). Till now, superposed states in EIT have been probed spectroscopically, through its signature of narrow transparency window in probe absorption profile. Here, we propose and experimentally explore a single shot, time domain measurement technique to quantify the generated coherence in EIT system of a dilute atomic ensemble at room temperature. The quantifier captures the effective ground state coherence and identifies two distinct regimes of EIT and Autler--Townes splitting (ATS). Using this quantifier as an indicator, we further demonstrate a mechanism to phase coherently control and freeze coherence by introducing an active decay compensation channel in the system. In the growing pursuit of quantum technologies at room temper, our results provide a unique way to phenomenologically quantify and coherently control quantum coherence in atom-like systems.\\ \\Reference:A. W. Laskar, N. Singh, P. Adhikary, A. Mukherjee, and S. Ghosh, Optica 5, 1462 (2018). [Preview Abstract] |
Friday, May 31, 2019 9:12AM - 9:24AM |
V06.00007: The application of coherent anti-Stokes Raman spectroscopy for remote molecular detection Jabir Chathanathil, Gengyuan Liu, Svetlana Malinovskaya A method is proposed theoretically to detect the presence of chemicals and hazardous contaminants in the atmosphere remotely by using the CARS (Coherent Anti-Stokes Raman Spectroscopy) technique. The anti-Stoke pulse scattered by air molecules distant from the source can be detected to determine their presence. The depletion of pulse amplitudes as they propagate through 1 km air is calculated. A semiclassical theory of nonlinear scattering without decoherence is used to find the Maxwell-Liouville-von Neumann equations for the pump, Stoke, probe and anti-Stoke components of the pulses. Two cases of incoming pulses, transform-limited and chirped with roof method, are examined for different pulse durations. For 100fs pulse duration, the coherence and the anti-Stoke enhancement are very high as predicted theoretically. A model in which the target molecule density has Gaussian distribution is proposed for this method. The change in energy of molecules as well as pulses at each scattering event is examined to verify the energy is conserved throughout the process. The conservation of total population of energy levels is tested as a second way of verification. The pulses are individually studied after each scattering event and a method is developed to extract the phase from each pulses. [Preview Abstract] |
Friday, May 31, 2019 9:24AM - 9:36AM |
V06.00008: Coupling organic molecules to nanophotonic devices Alex Clark Dibenzoterrylene (DBT) molecules are excellent sources of photons [1-3]. However to be useful all emitted photons must be collected to a single optical mode. To do this we employ nanophotonic waveguides. Previous demonstrations have relied on coupling to evanescent fields [2,3]. I will present our work coupling DBT in nano-trenches between two ends of a waveguide, where the molecules sit at the maximum of the guided electric field. I will present simulations of this system to show high coupling efficiencies are possible ($\beta\sim50\%$), before detailing our electron-beam lithography fabrication of silicon nitride on silica devices. We have fabricated micro-capillaries which cross at the nano-trench, into which we can flow an organic mixture of DBT and anthracene. Cooling to 4~K, we see observe lifetime-limited emission from DBT molecules in trenches. I will present our work in characterising the coupling and emission from these devices. Finally I will show that by adding tapered holes to the waveguide a nano-cavity can be formed to improve the coupling, enhance the emission rate, and make it uni-directional. [1] S. Grandi et al., Phys. Rev. A 94, 063839 (2016). [2] P. Lombardi et al., ACS Photonics 5, 126 (2017). [3] P. T\"{u}rschmann et al., Nano Lett. 17, 4941 (2017). [Preview Abstract] |
Friday, May 31, 2019 9:36AM - 9:48AM |
V06.00009: ABSTRACT WITHDRAWN |
Friday, May 31, 2019 9:48AM - 10:00AM |
V06.00010: Cascade random-quasi-phase-matched harmonic generation in polycrystalline ZnSe Herbie Smith, Rotem Kupfer, Hernan Quevedo, Luc Lisi, Ganesh Tiwari, C. Grant Richmond, Brant Bowers, Li Fang, B. Manuel Hegelich We experimentally studied cascade random-quasi-phase-matched harmonic generation in polycrystalline zinc selenide with a mid-infrared nanosecond laser. Observations show a sudden transition between two scaling regimes, below I\textasciicircum N and above I\textasciicircum N respectively, where I is the pump intensity and N is the harmonic order. To understand this phenomenon, we simulated the coupled three-wave mixing equations that govern the process on a domain of randomly-oriented, randomly-sized grains. We found that the phase-matching condition varies with grain size, indicating that grain size manipulation can be used as a pathway for phase-matching optimization of various wave mixing effects in polycrystalline materials. [Preview Abstract] |
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