共查询到20条相似文献,搜索用时 15 毫秒
1.
Riedrich-Möller J Kipfstuhl L Hepp C Neu E Pauly C Mücklich F Baur A Wandt M Wolff S Fischer M Gsell S Schreck M Becher C 《Nature nanotechnology》2012,7(1):69-74
Diamond is an attractive material for photonic quantum technologies because its colour centres have a number of outstanding properties, including bright single photon emission and long spin coherence times. To take advantage of these properties it is favourable to directly fabricate optical microcavities in high-quality diamond samples. Such microcavities could be used to control the photons emitted by the colour centres or to couple widely separated spins. Here, we present a method for the fabrication of one- and two-dimensional photonic crystal microcavities with quality factors of up to 700 in single crystal diamond. Using a post-processing etching technique, we tune the cavity modes into resonance with the zero phonon line of an ensemble of silicon-vacancy colour centres, and we measure an intensity enhancement factor of 2.8. The controlled coupling of colour centres to photonic crystal microcavities could pave the way to larger-scale photonic quantum devices based on single crystal diamond. 相似文献
2.
Diana FS David A Meinel I Sharma R Weisbuch C Nakamura S Petroff PM 《Nano letters》2006,6(6):1116-1120
We present a study of the light extraction from CdSe/ZnS core/shell colloidal quantum dot thin films deposited on quantum well InGaN/GaN photonic crystal structures. The two-dimensional photonic crystal defined by nanoimprint lithography is used to efficiently extract the guided light modes originating from both the quantum dot thin films and the InGaN quantum wells. Far-field photoluminescence spectra are used to measure the extraction enhancement factor of the quantum dot emission (x1.4). Microphotoluminescence measurements show that the guided mode effective extraction lengths range between 70 and 180 microm, depending on the wavelength of light. 相似文献
3.
Farrow T See P Bennett AJ Ward MB Atkinson P Cooper K Ellis DJ Unitt DC Ritchie DA Shields AJ 《Nanotechnology》2008,19(34):345401
We have fabricated a single-photon emitting diode based on a quantum dot in a micro-pillar cavity. By temperature tuning the dot emission into resonance with the cavity mode we see an enhancement in the collected photon intensity at 40?K. We perform autocorrelation measurements on the electroluminescence at fixed bias, observing photon anti-bunching. Due to the low resistance and capacitance of our device we can inject current pulses shorter than the lifetime of the quantum state, producing single-photon emission with g((2))(0) = 0.17. 相似文献
4.
We study the variation of the energy absorption rate in a hybrid semiconductor quantum dot-metallic nanoparticle system doped in a photonic crystal. The quantum dot is taken as a three-level V-configuration system and is driven by two applied fields (probe and control). We consider that one of the excitonic resonance frequencies is near to the plasmonic resonance frequency of the metallic nanoparticle, and is driven by the probe field. The other excitonic resonance frequency is far from both the plasmonic resonance frequency and the photonic bandgap edge, and is driven by the control field. In the absence of the photonic crystal we found that the system supports three excitonic-induced transparencies in the energy absorption spectrum of the metallic nanoparticle. We show that the photonic crystal allows us to manipulate the frequencies of such excitonic-induced transparencies and the amplitude of the energy absorption rate. 相似文献
5.
Three-dimensional optical control of individual quantum dots 总被引:1,自引:0,他引:1
We show that individual colloidal CdSe-core quantum dots can be optically trapped and manipulated in three dimensions by an infrared continuous wave laser operated at low laser powers. This makes possible utilizing quantum dots not only for visualization but also for manipulation, an important advantage for single molecule experiments. Moreover, we provide quantitative information about the magnitude of forces applicable to a single quantum dot and of the polarizability of an individual quantum dot. 相似文献
6.
Ren Q Lu J Tan HH Wu S Sun L Zhou W Xie W Sun Z Zhu Y Jagadish C Shen SC Chen Z 《Nano letters》2012,12(7):3455-3459
We demonstrate the spin selective coupling of the exciton state with cavity mode in a single quantum dot (QD)-micropillar cavity system. By tuning an external magnetic field, each spin polarized exciton state can be selectively coupled with the cavity mode due to the Zeeman effect. A significant enhancement of spontaneous emission rate of each spin state is achieved, giving rise to a tunable circular polarization degree from -90% to 93%. A four-level rate equation model is developed, and it agrees well with our experimental data. In addition, the coupling between photon mode and each exciton spin state is also achieved by varying temperature, demonstrating the full manipulation over the spin states in the QD-cavity system. Our results pave the way for the realization of future quantum light sources and the quantum information processing applications. 相似文献
7.
Nanoscale patterning of colloidal quantum dots on transparent and metallic planar surfaces 总被引:1,自引:0,他引:1
Y Park YG Roh UJ Kim DY Chung H Suh J Kim S Cheon J Lee TH Kim KS Cho CW Lee 《Nanotechnology》2012,23(35):355302
The patterning of colloidal quantum dots with nanometer resolution is essential for their application in photonics and plasmonics. Several patterning approaches, such as the use of polymer composites, molecular lock-and-key methods, inkjet printing and microcontact printing of quantum dots have been recently developed. Herein, we present a simple method of patterning colloidal quantum dots for photonic nanostructures such as straight lines, rings and dot patterns either on transparent or metallic substrates. Sub-10?nm width of the patterned line could be achieved with a well-defined sidewall profile. Using this method, we demonstrate a surface plasmon launcher from a quantum dot cluster in the visible spectrum. 相似文献
8.
Laser and strong coupling can coexist in a single quantum dot (QD) coupled to a photonic crystal nanocavity. This provides an important clue towards the realization of a quantum optical transistor. Using experimentally realistic parameters, in this work, theoretical analysis shows that such a quantum optical transistor can be switched on or off by turning on or off the pump laser, which corresponds to attenuation or amplification of the probe laser, respectively. Furthermore, based on this quantum optical transistor, an all-optical measurement of the vacuum Rabi splitting is also presented. The idea of associating a quantum optical transistor with this coupled QD-nanocavity system may achieve images of light controlling light in all-optical logic circuits and quantum computers. 相似文献
9.
Livneh N Strauss A Schwarz I Rosenberg I Zimran A Yochelis S Chen G Banin U Paltiel Y Rapaport R 《Nano letters》2011,11(4):1630-1635
We demonstrate a directional beaming of photons emitted from nanocrystal quantum dots that are embedded in a subwavelength metallic nanoslit array with a divergence angle of less than 4°. We show that the eigenmodes of the structure result in localized electromagnetic field enhancements at the Bragg cavity resonances, which could be controlled and engineered in both real and momentum space. The photon beaming is achieved using the enhanced resonant coupling of the quantum dots to these Bragg cavity modes, which dominates the emission properties of the quantum dots. We show that the emission probability of a quantum dot into the narrow angular mode is 20 times larger than the emission probability to all other modes. Engineering nanocrystal quantum dots with subwavelength metallic nanostructures is a promising way for a range of new types of active optical devices, where spatial control of the optical properties of nanoemitters is essential, on both the single and many photons level. 相似文献
10.
Willa Rawlinson 《Journal of Modern Optics》2013,60(13):1061-1067
We study the quantum discord for a system of two identical coupled quantum dots interacting with quantized cavity field in the presence of cavity as well as dot decay and detuning. The cavity is externally driven by a coherent light. These results are compared with the entanglement of the quantum dots in various parameter regimes in which system may or may not show bistability. We show that the discord in the steady state is nonzero for any nonzero cavity field amplitude. The system has higher discord in the upper branch of the bistability curve where the entanglement is zero. We also find many other interesting results including high discord and entanglement in the presence of detuning, a phenomenon which we further examine by approximating the density matrix in the appropriate limit. 相似文献
11.
Schramm A Tommila J Strelow C Hakkarainen TV Tukiainen A Dumitrescu M Mews A Kipp T Guina M 《Nanotechnology》2012,23(17):175701
We present the growth of single, site-controlled InAs quantum dots on GaAs templates using UV-nanoimprint lithography and molecular beam epitaxy. A large quantum dot array with a period of 1.5 μm was achieved. Single quantum dots were studied by steady-state and time-resolved micro-photoluminescence experiments. We obtained single exciton emission with a linewidth of 45 μeV. In time-resolved experiments, we observed decay times of about 670 ps. Our results underline the potential of nanoimprint lithography and molecular beam epitaxy to create large-scale, single quantum dot arrays. 相似文献
12.
Shorubalko I Leturcq R Pfund A Tyndall D Krischek R Schön S Ensslin K 《Nano letters》2008,8(2):382-385
A highly sensitive charge detector is realized for a quantum dot in an InAs nanowire. We have developed a self-aligned etching process to fabricate in a single step a quantum point contact in a two-dimensional electron gas and a quantum dot in an InAs nanowire. The quantum dot is strongly coupled to the underlying point contact that is used as a charge detector. The addition of one electron to the quantum dot leads to a change of the conductance of the charge detector by typically 20%. The charge sensitivity of the detector is used to measure Coulomb diamonds as well as charging events outside the dot. Charge stability diagrams measured by transport through the quantum dot and charge detection merge perfectly. 相似文献
13.
We present an instrument for performing correlation spectroscopy on single fluorescent particles while tracking their Brownian motion in three dimensions using real-time feedback. By tracking CdSe/ZnS quantum dots in water (diffusion coefficient approximately 20 microm2/s), we make the first measurements of photon antibunching (at approximately 10 ns) on single fluorophores free in solution and find fluorescence lifetime heterogeneity within a quantum dot sample. In addition, we show that 2-mercaptoethanol suppresses short time-scale intermittency (1 ms to 1 s) in quantum dot fluorescence by reducing time spent in the off-state. 相似文献
14.
Single-walled carbon nanotubes (SWCNTs) are considered for novel optoelectronic and quantum photonic devices, such as single photon sources, but methods must be developed to enhance the light extraction and spectral purity, while simultaneously preventing multiphoton emission as well as spectral diffusion and blinking in dielectric environments of a cavity. Here we demonstrate that utilization of nonpolar polystyrene as a cavity dielectric completely removes spectral diffusion and blinking in individual SWCNTs on the millisecond to multisecond time scale, despite the presence of surfactants. With these cavity-embedded SWCNT samples, providing a 50-fold enhanced exciton emission into the far field, we have been able to carry out photophysical studies for the first time with nanosecond timing resolution. We uncovered that fast spectral diffusion processes (1-3 ns) remain that make significant contributions to the spectral purity, thereby limiting the use of SWCNTs in quantum optical applications requiring indistinguishable photons. Measured quantum light signatures reveal pronounced photon antibunching (g(2)(0) = 0.15) accompanied by side-peak bunching signatures indicative of residual blinking on the submicrosecond time scale. The demonstrated enhanced single photon emission from cavity-embedded SWCNTs is promising for applications in quantum key distribution, while the demonstrated passivation effect of polystyrene with respect to the stability of the optical emission opens a novel pathway toward optoelectronic devices with enhanced performance. 相似文献
15.
光子晶体是一种具有光子带隙的新型材料,其概念提出比较早,距今已经过了30年。由于光子晶体具有很多新颖的特性,使其成为微纳光子学和量子光学的重要研究领域。随着微加工技术的进步和理论的深入研究,光子晶体在信息光学以及多功能传感器等其他多个学科中也得到广泛应用。本文从理论上详细综述了光子晶体的各种奇异特性,并从各种特性出发,详细介绍近年来光子晶体在光子晶体光纤、反射镜、滤波器、波导、低阈值激光器、多功能传感器、腔量子电动力学、偏振器、量子信息处理等领域的应用研究,并与传统的器件进行性能比较得出光子晶体器件具有无可比拟的优势。最后提出,随着3D打印制造技术的成熟,光子晶体材料必然会推动信息技术的新一轮革命。 相似文献
16.
We report on low-temperature measurements in a fully tunable carbon nanotube double quantum dot. A new fabrication technique has been used for the top-gates in order to avoid covering the whole nanotube with an oxide layer as in previous experiments. The top-gates allow us to form single dots and control the coupling between them, and we observe 4-fold shell filling. We perform inelastic transport spectroscopy via the excited states in the double quantum dot, a necessary step toward the implementation of new microwave-based experiments. 相似文献
17.
A. Högele S. Seidl M. Kroner K. Karrai R. J. Warburton M. Atatüre J. Dreiser A. Imamolu B. D. Gerardot P. M. Petroff 《Journal of Superconductivity》2005,18(2):245-249
The ground state of neutral and negatively charged excitons confined to a single self-assembled InGaAs quantum dot is probed in a direct absorption experiment by high resolution laser spectroscopy. We show how the anisotropic electron-hole exchange interaction depends on the exciton charge and demonstrate how the interaction can be switched on and off with a small dc voltage. Furthermore, we report polarization sensitive analysis of the excitonic interband transition in a single quantum dot as a function of charge with and without magnetic field. 相似文献
18.
The ground state of neutral and negatively charged excitons confined to a single self-assembled InGaAs quantum dot is probed in a direct absorption experiment by high resolution laser spectroscopy. We show how the anisotropic electron-hole exchange interaction depends on the exciton charge and demonstrate how the interaction can be switched on and off with a small dc voltage. Furthermore, we report polarization sensitive analysis of the excitonic interband transition in a single quantum dot as a function of charge with and without magnetic field. 相似文献
19.
S. Moriyama T. Fuse M. Suzuki Y. Aoyagi 《Science and Technology of Advanced Materials》2013,14(5-6):613-615
We demonstrate selecting a Coulomb peak which originates from a single quantum dot, from a bundle of many single-wall carbon nanotubes. The method uses the previously reported current flowing process, by which the number of nanotubes can be reduced for the transport. By adjusting the gate voltage in an appropriate range, the single peak belonging to the single quantum dot has been selected. The effect of the high frequency application on the peak has been investigated, and it is shown that the basic response can be explained by the adiabatic response of the single dot to the high frequency signal. 相似文献
20.
We investigate a scheme for implementing quantum dense coding via cavity decay and linear optics devices. Our scheme combines two distinct advantages: the atomic qubit serves as a stationary bit and the photonic qubit as a flying bit, thus it is suitable for long distant quantum communication. 相似文献