Coding data bits in the phase or polarisation state of single photons allows us to exploit wave particle duality for novel computing and communication protocols. The first practical applications are the fibre and free-space quantum cryptography apparatus used for secure exchange of keys [1,2]. Further developments such as quantum relays and other few qubit applications require that pairs of qubits interact. To avoid the inevitably weak non-linear interactions between photons conditional linear optics logic has been developed to demonstrate CNOT operation albeit with limited efficiency [3,4]. Optical quantum logic schemes thus require high efficiency sources and detectors of single photons. However, in the future we would also want non-linearity at the single photon level. These components in the quantum logic toolbox could be realised by exploiting wavelength scale engineering of optical structures. The strong modification of mode density within periodic dielectric structures can drastically modify spontaneous emission from two-level systems. This can manifest as changes in spectral content, changes in lifetime and in low power saturation (non-linear) effects. Suitable two-level systems could be colour centres in crystals, quantum dots in semiconductors and transition metals in glassy materials. Of interest to the field of quantum information are single two- level systems coupled to a strong resonant mode. Such a system could form the basis of a single photon source, a single photon detector and single photon non-linear element. This talk will explore these ideas in the context of micro-structured materials.
|Translated title of the contribution||Quantum information and Wavelength Scale Structures|
|Title of host publication||POWAG'04, Bath, UK|
|Publication status||Published - 12 Jul 2004|