Nonclassical radiation from diamond nanocrystals

The quantum properties of the fluorescence light emitted by diamond nanocrystals containing a single nitrogen-vacancy (NV) colored center is investigated. We have observed photon antibunching with very low background light. This system is therefore a very good candidate for the production of single photon on demand. In addition, we have measured larger NV center lifetime in nanocrystals than in the bulk, in good agreement with a simple quantum electrodynamical model.Comment: 8 pages, 5 figures, revised version, to appear in PR

Quantum plasmonics: second-order coherence of surface plasmons launched by quantum emitters into a metallic film

We address the issue of the second-order coherence of single surface plasmons launched by a quantum source of light into extended gold films. The quantum source of light is made of a scanning fluorescent nanodiamond hosting five nitrogen-vacancy (NV) color centers. By using a specially designed microscopy that combines near-field optics with far-field leakage-radiation microscopy in the Fourier space and adapted spatial filtering, we find that the quantum statistics of the initial source of light is preserved after conversion to surface plasmons and propagation along the polycrystalline gold film.Comment: Second version with minor changes made to comply with Referees' comments. Editorially approved for publication in Phys. Rev. B on 22 June 201

Dependence of the irradiation-induced growth kinetics of satellites on the nanoclusters dimension

A paraître dans NIM B, présenté par G. Rizza (LSI)International audienceIrradiation with MeV gold ions of embedded Au nanoclusters in silica matrix results in the formation of a ring of satellites in its surrounding. We show that changing the initial nanoclusters size modifies both the size and the density of the satellites, and therefore alters their kinetic growth. Finally we discuss the limitation of the ion implantation technique to form a model system to study the satellites kinetic growth and we propose a new approach based on the chemical synthesis of metallic nanoparticles to obtain the proper configuration

Room temperature stable single-photon source

We report on the realization of a stable solid state room temperature source for single photons. It is based on the fluorescence of a single nitrogen-vacancy (NV) color center in a diamond nanocrystal. Antibunching has been observed in the fluorescence light under both continuous and pulsed excitation. Our source delivers 2*10^4 single-photon pulses per second at an excitation repetition rate of 10 MHz. The number of two-photon pulses is reduced by a factor of five compared to strongly attenuated coherent sources.Comment: 7 pages, 10 figures, accepted to the special issue of the European Physical Journal D on "Quantum interference and cryptographic keys: novel physics and advancing technologies", proceedings of the conference QUICK 200

Traduire la diversité culturelle dans le roman de guerre postcolonial Allah n’est pas obligé d’Ahmadou Kourouma

L’article traite de la traduction du roman de guerre africain Allah n’est pas obligé d’Ahmadou Kourouma. De manière générale, le style de l’écrivain est connu pour les nombreux africanismes qui le colorent et l’enrichissent. Dans le roman mentionné, le narrateur veut s’adresser à tous les lecteurs possibles des romans francophones, c’est pourquoi sa narration entremêle des éléments linguistiques provenant de différentes aires culturelles (français littéraire, africanismes et anglicismes) et de différents registres (langue enfantine, langue familière, définitions du dictionnaire). Cette diversité linguistique oblige le traducteur du roman vers une langue étrangère (par exemple vers le slovène) à développer une stratégie cohérente basée sur l’analyse, dans laquelle la fonction de divers éléments dans la structure du récit sera d’abord déterminée (crédibilité psycho-linguistique, distance ironique pour souligner l’insupportabilité de la réalité décrite...) et ensuite le niveau de traduisibilité de ces éléments. En parallèle, nous examinerons comment la traductrice slovène du roman a résolu les problèmes et dans quelle mesure elle a réussi à transférer dans sa langue la diversité linguistique du roman d’Ahmadou Kourouma

Balanced homodyne detection in second-harmonic generation microscopy

We demonstrate the association of two-photon nonlinear microscopy with balanced homodyne detection for investigating second harmonic radiation properties at nanoscale dimensions. Variation of the relative phase between second-harmonic and fundamental beams is retrieved, as a function of the absolute orientation of the nonlinear emitters. Sensitivity down to approximately 3.2 photon/s in the spatio-temporal mode of the local oscillator is obtained. This value is high enough to efficiently detect the coherent second-harmonic emission from a single KTiOPO4 crystal of sub-wavelength size.Comment: 9 pages to appear in Applied Physics Letter

Spin relaxometry of single nitrogen-vacancy defects in diamond nanocrystals for magnetic noise sensing

We report an experimental study of the longitudinal relaxation time ($T_1$) of the electron spin associated with single nitrogen-vacancy (NV) defects hosted in nanodiamonds (ND). We first show that $T_1$ decreases over three orders of magnitude when the ND size is reduced from 100 to 10 nm owing to the interaction of the NV electron spin with a bath of paramagnetic centers lying on the ND surface. We next tune the magnetic environment by decorating the ND surface with Gd$^{3+}$ ions and observe an efficient $T_{1}$-quenching, which demonstrates magnetic noise sensing with a single electron spin. We estimate a sensitivity down to $\approx 14$ electron spins detected within 10 s, using a single NV defect hosted in a 10-nm-size ND. These results pave the way towards $T_1$-based nanoscale imaging of the spin density in biological samples.Comment: Main text with 4 figures together with supplemental informatio

Traduction des connotations autonymiques dans trois romans de Michel Houellebecq

This paper deals with the autonyms or the widespread, orthographically indeterminate use of italics and quotation marks in Slovene translations of three of Houellebecq’s novels, which have been elaborated by three different Slovene translators. Autonyms are divided into three main categories according to whether they convey the words of definite or indefinite individuals, the language of the narrator himself or the concepts and values of the whole society. Within the framework of a style often qualified as “white”, the extended use of italics and quotation marks with function of autonymic connotation allows the author to transmit to the reader very fine semantic nuances and contributes to the richness of his work. Like metaphorical networks, stylems such as the recurrent and extended use of italics and quotation marks require from the translator a preliminary work of interpretation and the development of a coherent strategy making it possible to preserve intact the function of these elements in the narrative. Although the three translations analysed can be considered as globally faithful to Houellebecq’s texts and made possible the notoriety of the French writer in Slovenia, none of them is distinguished by a rigorous and coherent treatment of autonymic connotations indicated by non-normative use of italics and quotation marks. The most frequent and damaging anomalies are the maintenance of these visual signs where the expressions indicated in French do not have to be in Slovenian or, on the contrary, their elimination where it is perfectly possible and appropriate to maintain them for the detailed understanding of the text. The author draws attention to possible solutions and opts for the elaboration of a consistent translation strategy for the treatment of the analysed elements

Single photon quantum cryptography

We report the full implementation of a quantum cryptography protocol using a stream of single photon pulses generated by a stable and efficient source operating at room temperature. The single photon pulses are emitted on demand by a single nitrogen-vacancy (NV) color center in a diamond nanocrystal. The quantum bit error rate is less that 4.6% and the secure bit rate is 9500 bits/s. The overall performances of our system reaches a domain where single photons have a measurable advantage over an equivalent system based on attenuated light pulses.Comment: 4 pages, 3 figure