| Improving the fidelity of optical Zeno gates via distillation University of Calgary | Publication | 2006-12-01 | P. M. Leung, T. C. Ralph |
| Spectral effects of strong χ ( 2 ) nonlinearity for quantum processing University of Calgary | Publication | 2009-04-01 | P. M. Leung, W. J. Munro, K. Nemoto, T. C. Ralph |
| Optical zeno gate: bounds for fault tolerant operation University of Calgary | Publication | 2007-07-01 | P. M. Leung, T. C. Ralph |
| Coherent control of microwave pulse storage in superconducting circuits University of Calgary | Publication | 2012-01-01 | P. M. Leung, B. C. Sanders |
| Electromagnetically induced transparency on an array of artificial atomsElectromagnetically induced transparency (EIT) has recently been demonstrated in a one-dimensional superconducting artificial atom in the microwave regime [1] and it is of interest to build quantum information devices with artificial atoms. Since one can flexibly engineer the properties of artificial atoms and the spatial dimension is reduced from three to one, artificial atoms has the potential to become a useful test bed for photonics. For instance, it is in theory impossible to induce a phase shift large enough for useful quantum gates with single photons via cross-phase modulation [2], and one may test the validity of the theory with microwave photons and artificial atoms. Here we develop the theory of a one-dimensional array of superconducting artificial atoms with EIT. Our theory shows how the absorption of the field in a one-dimensional array of atoms behaves similar to Beer’s law and how the controlled field induces transparency in the array of atoms. Our theory also shows how EIT properties, such as the reduction of group-velocity, are achieved for microwave pulses in artificial atoms. [1] A.A. Abdumalikov Jr. et al, Phys. Rev. Lett., 104, 193601 (2010) [2] J. Gea-Banacloche, Phys. Rev. A, 81, 043823 (2010) University of Calgary | Presentation | 2011-02-18 | P. M. Leung |
| Storing a Microwave Pulse in Artificial Atoms with Electromagnetically Induced Transparency University of Calgary | Presentation | 2011-07-06 | P. M. Leung, B. C. Sanders |
| Requirements on strong chi-2 nonlinearity for parametric conversion and using optical nonlinearity for Bell measurementOptical chi-2 nonlinearity has broad applications in optical technology. Although current materials only provide weak nonlinearity, there has been improvements towards producing materials with stronger strength. However, strong nonlinearity means higher order interactions between photons are significant and we show that the frequency response of a bulk chi-2 medium may induce spectral entanglement between photons that lowers the conversion rate. We prove that one way of reducing the spectral entanglement is to utilize periodically poled media. Here we also show how one may use currently available optical nonlinearity to do Bell measurements that can outperform the linear optical partial Bell measurement scheme. University of Calgary | Presentation | 2010-08-30 | P. M. Leung |
| Low-loss surface modes and lossy hybrid modes in metamaterial waveguides University of Calgary | Publication | 2012-01-01 | B. Lavoie, P. M. Leung, B. C. Sanders |
| Slow light with three-level atoms in metamaterial waveguides University of Calgary | Publication | 2013-01-01 | B. Lavoie, P. M. Leung, B. C. Sanders |
| Metamaterial Waveguides University of Calgary | Presentation | 2011-08-29 | B. Lavoie, P. M. Leung, B. C. Sanders |
| All-optical control in metamaterial-dielectric waveguidesWe explore the possibility of all-optical control of weak signals in waveguides having a dielectric core and a metamaterial cladding (metamaterial-dielectric waveguide). To this end we present a characterization of slab and cylindrical metamaterial-dielectric waveguides. To describe the permittivity of the metamaterial we use the lossy Drude model and for the permeability we use a lossy Lorentz-Drude model. We find that metamaterial-dielectric waveguides support modes with lower attenuation than metal-dielectric guides through expulsion of the fields from the metamaterial. The field expulsion also provides good transverse confinement in the cylindrical guide.
We propose using slow light to effect all-optical control in metamaterial waveguides. To slow the light, we employ electromagnetically induced transparency by pumping, with a strong control field, 3-level atoms embedded in the dielectric core. Pumping the atoms using a waveguide mode elicits a nonlinear response that results in a spatially graded refractive index in the core of the guide. The resulting refractive index depends on the strength and the transverse profile of the control field. We use the results of the aforementioned characterization to determine the properties of the control field (e.g. transverse profile). A signal field can then be manipulated by changing the parameters of the control field. All-optical control schemes, such as this, could be exploited for ultra-fast optical switches or quantum information processing applications. University of Calgary | Presentation | 2012-06-12 | B. Lavoie, P. M. Leung, B. C. Sanders |
| Waveguide characteristics for arbitrary permittivity and permeability including for metamaterials University of Calgary | Presentation | 2011-08-25 | B. Lavoie, P. M. Leung, B. C. Sanders |
