Optical Fiber Communication Conference

Tools for practical Quantum cryptography

Christian Kurtsiefer, S. Mayer, M. Halder, Harald Weinfurter, Patrick Zarda

Published Jan 1, 2001• 0 citations

Abstract

Quantum cryptography is moving from laboratory demonstrations towards technical devices. We present a miniature realization of a BB84-based system, and discuss a true solid-state single photon source based on fluorescence from NV-centers in diamond.

DOI: 10.1364/icqi.2001.pa4

Related papers

Solid-state source of single photons for quantum cryptography and student-labs

Chunlang Wang, Christoph Braig, Patrick Zarda +2 more

We report on the experimental investigation of fluorescence obtained from single N-V or Si-V centers in diamond. The simple set-up is well suited for quantum cryptography applications as well as for advanced student-labs.

Conference on Lasers and Electro-OpticsJan 1, 20040 citations

Stable Solid-State Source of Single Photons

Patrick Zarda, Christian Kurtsiefer, Sonja Mayer +1 more

The controlled generation of single photons is mandatory for applications in quantum communication, in particular for secure quantum cryptography, and also for a number of fundamental problems in quantum optics. Here, we present a stable all solid-state source for single photons utilizing the fluorescence light from a single nitrogen-vacancy center (N-V center) in diamond.

Kluwer Academic Publishers eBooksFeb 24, 200652 citations

A single photon source based on NV centers in diamond nanocrystals

Juliane Bahe, Xiaoqing Zhou, Tobias Jan Kippenberg +4 more

The development of reliable devices to generate single photons is crucial for applications in quantum cryptography, as well as for fundamental quantum optics experiments. Due to their extremely high photostability at room temperature, optically active defects in solids, the so called color centers, are among the most promising candidates. Single NV (nitrogen-vacancy) centers in diamond have been demonstrated to be able to generate single photons and have already shown advantages compared to attenuated laser pulses in a quantum cryptography experiment. The nitrogen-vacancy center (NV center) in diamond consists of a substitutional nitrogen atom and an adjacent vacancy. This complex exhibits an optical transition with a fluorescence lifetime of 11.6 ns. The room temperature spectrum of the NV center consists of the zero-phonon line at 637 nm and broad phononic sidebands with a FWHM of more than 100 nm. Due to the existence of a shelving level the efficiency of the NV center as a single photon source is limited. Additionally, the high diffraction index of bulk diamond restricts the efficiency to collect the fluorescence light.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Jun 1, 20094 citations

Single photon quantum cryptography and devices

Andrew J. Shields

A natural strategy for realizing practical single-photon devices is to adapt current semiconductor light emitters and detectors. I discuss progress towards a single-photon technology based upon integrating self-organised quantum dots into conventional optoelectronic devices.

Conference on Lasers and Electro-OpticsJan 1, 20040 citations

Investigation of multi-bunching by generating multi-order fluorescence of NV center in diamond

Haijun Tang, Irfan Ahmed, Pargorn Puttapirat +4 more

Fabricating electronics from solid-state quantum emitters is a promising strategy for the miniaturization and integration of electronic devices. However, the practical realization of solid-state quantum devices and circuits for signal transmission and processing at room temperature has remained challenging. Herein, we investigated the multi-bunching phenomenon by generating multi-order fluorescence from a pseudo-thermal source at room temperature using the nitrogen-vacancy (NV) center in diamond. We demonstrate the shift in time of multi-bunching by controlling the effect of dressing to realize logical gates and transistor switching operations. We also suggest the optimization of the time propagation delay (TPD) of the gate circuit by changing the boxcar gate position.

Physical Chemistry Chemical PhysicsJan 1, 201810 citations

Engineering of the photonic environment of single nitrogen-vacancy centers in diamond

Daniel Riedel

The nitrogen-vacancy (NV) center in diamond has an optically addressable, highly coherent spin. However, an NV center even in high quality single-crystalline material is a very poor source of single photons: extraction out of the high-index diamond is inefficient, the emission of coherent photons represents just a few per cent of the total emission, and the decay time is large. In principle, all three problems can be addressed with a resonant microcavity, which significantly boosts the emission rate of coherent photons into the cavity mode based on the Purcell effect. In practice though, it has proved difficult to implement this concept: photonic engineering hinges on nano-fabrication yet it is notoriously difficult to process diamond without degrading the NV centers. \nIn this thesis, we present a microcavity scheme which employs minimally processed diamond membranes, thereby preserving the high quality of the starting material. The miniaturized plano-concave Fabry-Perot microcavity platform features full in situ spatial and spectral tunability. We demonstrate a clear change in the lifetime for multiple individual NV centers on tuning both the cavity frequency and anti-node position. The overall Purcell factor for the zero-phonon line (ZPL) of ~30 translates to an increase in the ZPL emission probability from ~3% to ~46%. \nFurthermore, we report the creation of a low-loss, broadband optical antenna giving highly directed output from a coherent single spin in the solid state. The device, the first crystalline solid-state realization of a dielectric antenna, is engineered for individual NV electronic spins in diamond. The photonic structure preserves the high spin coherence of single-crystalline diamond (T2 ~100µs). We demonstrate a directionality of close to 10 and single photon count rates approaching one MHz. The analysis of the angular emission pattern of our device suggests that 95% of the broadband NV fluorescence is channeled into a solid angle corresponding to a numerical aperture of 0.8. \nThe abovementioned approaches feature complementary benefits. The narrowband enhancement of the ZPL emission rate provided by the microcavity benefits applications in quantum information processing relying on coherent photons. With the prospect of integrating lifetime-limited emitters and achieving a high ZPL collection efficiency our results pave the way for much enhanced spin-photon and spin-spin entanglement rates. On the other hand, by channeling the major fraction of the broadband NV fluorescence into a narrow solid angle the dielectric optical antenna facilitates efficient spin readout. Our approach enables a near-unity collection efficiency which, upon mitigation of the known photon losses, renders it a potential key technology for quantum sensing applications. \n

Jan 1, 20172 citations