| Adiabatic frequency conversion of optical information in atomic vapor University of Calgary | Publication | 2007-01-01 | F. Vewinger, J. Appel, E. Figueroa, A. Lvovsky |
| Adiabatic frequency conversion of quantum optical information in atomic vapor University of Calgary | Publication | 2007-01-01 | F. Vewinger, J. Appel, E. Figueroa, A. Lvovsky |
| Recent developments in quantum optics in Calgary University of Calgary | Presentation | 2006-01-05 | F. Vewinger |
| Quantum control of atomic and optical states University of Calgary | Presentation | 2006-03-08 | F. Vewinger |
| Control of coherent superpositions of degenerate states using adiabatic transfer University of Calgary | Presentation | 2006-03-15 | F. Vewinger |
| Universal homodyne detector with high bandwidthWir stellen einen Homodyne-Detektor mit einer Bandbreite >
200 MHz vor. Ein Ti:Sa Laser (Coherent Mira, 76 MHz Pulswiederholrate)
dient als Lokaloszillator in einem balancierten Detektionsschema. Die
Pulse werden mittels zweier vorgespannter Si-PIN Fotodioden detektiert,
deren Differenzstrom in einem als Transimpedanzwandler geschalteten
Operationsverst¨arker verst¨arkt wird. Bei einer Leistung von 10 mW des
Lokaloszillators liegt das optische Schrotrauschen bis zu 15 dB ¨uber dem
elektronischen Rauschen des Detektors. Die hohe Bandbreite des Detektors
erlaubt Messungen sowohl im Frequenz- als auch im Zeitraum bei
der vollen Pulswiederholrate des Lokaloszillators, z.B. f¨ur Quantenkommunikation
mit kontinuierlichen Variablen. University of Calgary | Presentation | 2006-03-13 | F. Vewinger, S. Babichev, J. Appel, A. Lvovsky |
| Raman adiabatic transfer of optical statesWir pr¨asentieren ein Protokoll zum Transfer von Quantenzust¨anden
zwischen zwei optischenModen basierend auf elektromagnetisch induzierter
Transparenz. Wird ein metastabiler Zustand durch zwei (klassische)
Kontrollfelder an zwei angeregte Zust¨ande gekoppelt, welche wiederum
mittels zweier (quantisierter) Signalfelder an einen weiteren metastabilen
Zustand gekoppelt sind (Multi- Konfiguration), so laesst sich durch
die geeignete Wahl der Kontrollelder der Quantenzustand eines Signalfeldes
adiabatisch auf die zweite Signalmode ¨ubertragen. Wir pr¨asentieren
ein theoretisches Modell, welches den Transfer beschreibt, sowie erste
Ergebnisse auf dem Weg zur experimentellen Implementierung in Rubidiumdampf. University of Calgary | Presentation | 2006-03-13 | F. Vewinger, J. Appel, E. Figueroa, G. Günter, K. Marzlin, A. Lvovsky |
| Characterization of atomic coherence decay for the storage of light University of Calgary | Publication | 2006-08-01 | E. Figueroa, F. Vewinger, J. Appel, G. Günter, A. Lvovsky |
| Time-resolved probing of the ground state coherence in rubidium University of Calgary | Publication | 2007-01-01 | M. Oberst, F. Vewinger, A. Lvovsky |
| Decoherence of electromagnetically-induced transparency in atomic vapor University of Calgary | Publication | 2006-01-01 | E. Figueroa, F. Vewinger, J. Appel, A. Lvovsky |
| Characterization of atomic coherence decay for storage of light experiments University of Calgary | Presentation | 2006-08-14 | E. Figueroa, F. Vewinger, J. Appel, A. Lvovsky, G. Günter |
| Adiabatic transfer of quantum optical information by means of electromagnetically-induced transparency University of Calgary | Presentation | 2006-07-25 | J. Appel, F. Vewinger, E. Figueroa, G. Günter, K. Marzlin, A. Lvovsky |
| Adiabatic transfer of quantum optical information in atomic vaporWe demonstrate a quantum communication protocol (RATOS) that enables frequency conversion and routing of quantum optical information in an adiabatic and robust way. The protocol is based on EIT in systems with multiple excited levels. Article not available. University of Calgary | Presentation | 2006-10-08 | E. Figueroa, F. Vewinger, J. Appel, A. Lvovsky |
| Decoherence in electromagnetically-induced transparency University of Calgary | Presentation | 2006-02-25 | J. Appel, E. Figueroa, F. Vewinger, G. Günter, K. Marzlin, A. Lvovsky |
| Controlling light by electromagnetically-induced transparency University of Calgary | Presentation | 2006-05-07 | J. Appel, E. Figueroa, F. Vewinger, G. Günter, K. Marzlin, A. Lvovsky |
| Characterization of decoherence in electromagnetically induced transparency for applications in storage of lightElectromagnetically-induced transparency (EIT) has many applications in quantum information, particularly in quantum memory for light [1]. These applications require understanding of the phenomena responsible for decoherence in such processes. Insight into this question can be gained by measuring the width of the EIT resonance as a function of the pump field intensity. We report characterization of EIT resonances in the D1 line of Rb 87 under various experimental conditions. The dependence of the EIT linewidth on the power of the control field was investigated, at various temperatures, for lambda level configurations associated with different hyperfine levels of the atomic ground state as well as magnetic sublevels of the same hyperfine level. Strictly linear behavior was observed in all cases. Our results were inconsistent with a widely accepted theory where population exchange between the ground levels is assumed to be the main decoherence mechanism [2]. We therefore formulated a new theory assuming pure dephasing (decay of off-diagonal matrix elements) as the new mechanism. Our data shows this theory to be in good agreement with our experiments. 1. D. F. Phillips, A. Fleischhauer, A. Mair, R. L. Walsworth, and M. D. Lukin, Phys. Rev. Lett. \textbf{86}, 783 (2001). 2. H. Lee, Y. Rostovtsev, C. J. Bednar, and A. Javan, Appl. Phys. B \textbf{76}, 33 (2003).
University of Calgary | Presentation | 2007-06-07 | E. Figueroa, J. Appel, F. Vewinger, A. Lvovsky |
| Routing of optical states by atomic mediaElectromagnetically induced transparency (EIT) is a quantum interference
effect, in which a weak signal light field and a stronger control field
drive atomic transitions with a common excited state. The quantum
interference between both light-atom interactions leads to strong
dispersion which causes phenomena such as slowdown and stopping of
light and can be used for enhanced nonlinear interaction.
We extended the standard quantum theory of EIT to accommodate for
multiple excited levels and show experimentally that a transfer of
optical quantum states between different signal modes can be
implemented by an adiabatic change of the control fields.
Raman adiabatic transfer of optical states resembles stimulated Raman
adiabatic passage (STIRAP) but applies to optical rather than atomic
states. It can be used to route and distribute optically encoded
information in classical and quantum communication.
We performed experiments using the hyperfine levels of Rb87 atoms
at the D1 line: First, a signal pulse (resonant to the F=1,
F'=1 transition) was placed into the cell under EIT conditions created
by a control laser (resonant to F=2, F'=1). Then adiabatically this
laser is switched off while another control laser (resonant to F=2,
F'=2) is switched on. This procedure transfers the information carried
by the state of the original signal pulse to the optical mode resonant
with the F=1, F'=2 transition. University of Calgary | Presentation | 2006-05-02 | J. Appel, E. Figueroa, F. Vewinger, K. Marzlin, A. Lvovsky |
| Routing of optical states by atomic media University of Calgary | Presentation | 2006-05-21 | J. Appel, E. Figueroa, F. Vewinger, A. Lvovsky |
| Experimental Raman adiabatic transfer of optical states in rubidiumAn essential element of a quantum optical communication network is a tool for transferring and/or distributing quantum information between optical modes (possibly of different frequencies) in a loss- and decoherence-free fashion. We present a theory [1] and an experimental demonstration [2] of a protocol for routing and frequency conversion of optical quantum information via electromagnetically-induced transparency in an atomic system with multiple excited levels. Transfer of optical states between different signal modes is implemented by adiabatically changing the control fields. The proof-of-principle experiment is performed using the hyperfine levels of the rubidium D1 line. [1] F. Vewinger, J. Appel, E. Figueroa, A. I. Lvovsky, quant-ph/0611181 [2] J. Appel, K.-P. Marzlin, A. I. Lvovsky, Phys. Rev. A \\textbf{73}, 013804 (2006) University of Calgary | Presentation | 2007-06-08 | J. Appel, E. Figueroa, F. Vewinger, K. Marzlin, A. Lvovsky |
| Towards storage of squeezed light by electromagnetically induced transparencyElectromagnetically induced transparency (EIT) is a quantum interference effect, in which a strong control laser beam changes a medium's linear dispersion and absorption in such a way that a weak signal beam travels without absorption and its group velocity is greatly reduced. Theoretical models and recent experiments predict that adiabatic switching of the control field while the signal is inside the medium reversibly maps the signal quantum state to the states of the irradiated atoms. We report on our recent progress in storing and retrieving a squeezed optical state by adiabatic conversion to a collective coherent superposition of the hyperfine ground levels of the D1 transition in rubidium-87. A bright narrowband source of nonclassical light for interaction with atoms has been constructed based on an optical parametric amplifier featuring a periodically poled KTP crystal. Ultrafast lossless switching allows us to generate 1 $\mu$s pulses of up to 3 dB squeezed vacuum resonant to the EIT transparency window. We investigate the transmission and storage of these states under EIT conditions by homodyne tomography.
University of Calgary | Presentation | 2007-06-09 | J. Appel, E. Figueroa, F. Vewinger, D. Korystov, G. Günter, A. Lvovsky |
| Towards storage of non-classical light using electromagnetically induced transparencyElectromagnetically induced transparency (EIT) is a quantum interference effect in which a strong control laser beam changes a medium's linear dispersion and absorption allowing a weak signal beam to travel without absorption and with its group velocity greatly reduced. This allows the storage of quantum information on the irradiated atoms. We report on our recent progress in storing and retrieving a squeezed optical state using hyperfine ground levels of the D1 transition in rubidium-87. A narrowband source of nonclassical light for interaction with atoms has been constructed based on parametric amplification featuring a periodically poled KTP crystal. Ultrafast lossless switching allows us to generate 1 us pulses of up to 3 dB squeezed vacuum resonant to the EIT transparency window. We investigate the transmission and storage of these states under EIT conditions by homodyne tomography. University of Calgary | Presentation | 2007-08-11 | E. Figueroa, J. Appel, F. Vewinger, D. Korystov, G. Günter, A. Lvovsky |
| Instant single-photon Fock state tomography University of Calgary | Publication | 2009-01-01 | S. R. Huisman, N. Jain, S. Babichev, F. Vewinger, A. -. Zhang, S. -. Youn, A. Lvovsky |
| Electromagnetically-induced transparency in systems with multiple excited levels University of Calgary | Presentation | 2006-11-30 | A. Lvovsky, J. Appel, E. Figueroa, G. Günter, F. Vewinger, K. Marzlin |
