The broadband enhancement of single‑photon emission from nitrogen‐vacancy centers in nanodiamonds coupled to a planar multilayer metamaterial with hyperbolic dispersion is studied experimentally. The metamaterial is fabricated as an epitaxial metal/dielectric superlattice consisting of CMOS‐compatible ceramics: titanium nitride (TiN) and aluminum scandium nitride (AlxSc1‐xN). It is demonstrated that employing the metamaterial results in significant enhancement of collected single‑photon emission and reduction of the excited‐state lifetime. Our results could have an impact on future CMOS‐compatible integrated quantum sources.
The goal of this paper is double. First, we illustrate a method for studying the bifurcation of limit cycles from the continuum
periodic orbits of a k-dimensional isochronous center contained in ℝn with n ⩾ k, when we perturb it in a class of differential systems. The method is based in the averaging theory. Second, we consider a particular polynomial differential
system in the plane having a center and a non-rational first integral. Then we study the bifurcation of limit cycles from
the periodic orbits of this center when we perturb it in the class of all polynomial differential systems of a given degree.
As far as we know this is one of the first examples that this study can be made for a polynomial differential system having
a center and a non-rational first integral.
The first and third authors are partially supported by a MCYT/FEDER grant MTM2005-06098-C01, and by a CIRIT grant number 2005SGR-00550.
The second author is partially supported by a FAPESP–BRAZIL grant 10246-2. The first two authors are also supported by the
joint project CAPES–MECD grant HBP2003-0017. 相似文献
Structurally complex diazo-containing scaffolds are formed by conjugate addition to vinyl diazonium salts. The electrophile, a little studied α-diazonium-α,β-unsaturated carbonyl compound, is formed at low temperature under mild conditions by treating β-hydroxy-α-diazo carbonyls with Sc(OTf)3. Conjugate addition occurs selectively at the 3-position of indole to give α-diazo-β-indole carbonyls, and enoxy silanes react to give 2-diazo-1,4-dicarbonyl products. These reactions result in the formation of tertiary and quaternary centers, and give products that would be otherwise difficult to form. Importantly, the diazo functional group is retained within the molecule for future manipulation. Treating an α-diazo ester indole addition product with Rh2(OAc)4 caused a rearrangement to occur to give a 2-(1H-indol-3-yl)-2-enoate. In the case of diazo ketone compounds, this shift occurred spontaneously on prolonged exposure to the Lewis acidic reaction conditions. 相似文献