Many chemical methods have been developed to favor a particular product in transformations of compounds that have two or more reactive sites. We explored a different approach to site selectivity ...using vibrational strong coupling (VSC) between a reactant and the vacuum field of a microfluidic optical cavity. Specifically, we studied the reactivity of a compound bearing two possible silyl bond cleavage sites-Si-C and Si-O, respectively-as a function of VSC of three distinct vibrational modes in the dark. The results show that VSC can indeed tilt the reactivity landscape to favor one product over the other. Thermodynamic parameters reveal the presence of a large activation barrier and substantial changes to the activation entropy, confirming the modified chemical landscape under strong coupling.
Light in tiny holes Genet, C; Ebbesen, T. W
Nature,
01/2007, Letnik:
445, Številka:
7123
Journal Article
Recenzirano
The presence of tiny holes in an opaque metal film, with sizes smaller than the wavelength of incident light, leads to a wide variety of unexpected optical properties such as strongly enhanced ...transmission of light through the holes and wavelength filtering. These intriguing effects are now known to be due to the interaction of the light with electronic resonances in the surface of the metal film, and they can be controlled by adjusting the size and geometry of the holes. This knowledge is opening up exciting new opportunities in applications ranging from subwavelength optics and optoelectronics to chemical sensing and biophysics.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We demonstrate that photochromic molecules enable switching from the weak- to ultrastrong-coupling regime reversibly, by using all-optical control. This switch is achieved by photochemically inducing ...conformational changes in the molecule. Remarkably, a Rabi splitting of 700 meV is measured at room temperature, corresponding to 32% of the molecular transition energy. A similar coupling strength is demonstrated in a plasmonic structure. Such systems present a unique combination of coupling strength and functional capacities.
We discuss a technique to strongly couple a single target quantum emitter to a cavity mode, which is enabled by virtual excitations of a nearby mesoscopic ensemble of emitters. A collective coupling ...of the latter to both the cavity and the target emitter induces strong photon nonlinearities in addition to polariton formation, in contrast to common schemes for ensemble strong coupling. We demonstrate that strong coupling at the level of a single emitter can be engineered via coherent and dissipative dipolar interactions with the ensemble, and provide realistic parameters for a possible implementation with SiV^{-} defects in diamond. Our scheme can find applications, amongst others, in quantum information processing or in the field of cavity-assisted quantum chemistry.
Much effort over the past decades has been focused on improving carrier mobility in organic thin-film transistors by optimizing the organization of the material or the device architecture. Here we ...take a different path to solving this problem, by injecting carriers into states that are hybridized to the vacuum electromagnetic field. To test this idea, organic semiconductors were strongly coupled to plasmonic modes to form coherent states that can extend over as many as 10(5) molecules and should thereby favour conductivity. Experiments show that indeed the current does increase by an order of magnitude at resonance in the coupled state, reflecting mostly a change in field-effect mobility. A theoretical quantum model confirms the delocalization of the wavefunctions of the hybridized states and its effect on the conductivity. Our findings illustrate the potential of engineering the vacuum electromagnetic environment to modify and to improve properties of materials.
Light usually diffracts in all directions when it emerges from a subwavelength aperture, which puts a lower limit on the size of features that can be used in photonics. This limitation can be ...overcome by creating a periodic texture on the exit side of a single aperture in a metal film. The transmitted light emerges from the aperture as a beam with a small angular divergence (approximately ±3°) whose directionality can be controlled. This finding is especially surprising, considering that the radiating region is mainly confined to an area with lateral dimensions comparable to the wavelength of the light. The device occupies no more than one cubic micrometer and, when combined with enhanced transmission, suggests that a wide range of photonic applications is possible.
Light passing through subwavelength apertures Garcia-Vidal, F. J.; Martin-Moreno, L.; Ebbesen, T. W. ...
Reviews of modern physics,
03/2010, Letnik:
82, Številka:
1
Journal Article
Images of the assembly of surfactants and synthetic lipids on the surface of carbon nanotubes were obtained by transmission electron microscopy. Above the critical micellar concentration, sodium ...dodecyl sulfate (SDS) forms supramolecular structures made of rolled-up half-cylinders on the nanotube surface. Depending on the symmetry and the diameter of the carbon nanotube, we observed rings, helices, or double helices. Similar self-assemblies were also obtained with several synthetic single-chain lipids designed for the immobilization of histidine-tagged proteins. At the nanotube-water interface, permanent assemblies were produced from mixed micelles of SDS and different water-insoluble double-chain lipids after dialysis of the surfactant. Such arrangements could be further exploited for the development of new biosensors and bioelectronic nanomaterials.
A subwavelength aperture is a key element in near-field optical devices and many recent photonic structures. When the lateral dimensions of such aperture is smaller than half the wavelength, light ...cannot propagate through the hole and the transmission is typically very weak. It is usually believed to scale as the fourth power of the aperture diameter, a result first stated by Bethe Phys. Rev. 66 (1944) 163 in 1944 by analyzing the transmission through a small hole in an infinitely thin perfectly metal screen. However, a real subwavelength aperture is very different because the thickness and the finite conductivity of the metal has significant consequences which are far from being well understood. Here we report that light impinging on isolated subwavelength holes in real metal film, in this case Ag, excite localized surface plasmon modes on the aperture ridge. Their activation gives rise to optical tunneling with unexpected enhanced transmission peaks and directionality. These properties follow from the dipolar nature of the LSP modes and can be tuned by an appropriate design of the aperture shape. These findings are of relevance for the current trends in subwavelength optics.
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