Rational engineering of light-matter interactions: From optical metasurfaces to printing single fluorescent molecules
Open access
Autor(in)
Datum
2020-05Typ
- Doctoral Thesis
ETH Bibliographie
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Persistenter Link
https://doi.org/10.3929/ethz-b-000413678Publikationsstatus
publishedExterne Links
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Beteiligte
Referent: Poulikakos, Dimos
Referent: Sandoghdar, Vahid
Referent: Novotny, Lukas
Referent: Eghlidi, Hadi
Verlag
ETH ZurichOrganisationseinheit
03462 - Poulikakos, Dimos (emeritus) / Poulikakos, Dimos (emeritus)
Anmerkungen
The peculiar interaction of electromagnetic radiation with the atoms and molecules composing matter lies at the center of many phenomena and processes encountered in nature and modern day advanced technologies. Rationally tailoring this interaction allows for controlling the propagation, spectrum, polarization or even the quantum nature of light. However, due to the wave nature of light, the effective engineering of this interaction requires a structuring of matter at wavelength or subwavelength dimensions, and a precise and hybrid integration of materials at the nanoscale. This thesis focuses on rationally tailoring the interaction of light and matter through artificially designed nanostructured surfaces, so-called metasurfaces, and novel approaches to nanofabrication, in particular electrohydrodynamic nanoprinting. This includes the manipulation of light and its sources at the nanoscale both in the classical and quantum regime. In this effort, we focus on three specific problems of interest: the extreme manipulation of the propagation of light by a metasurface, the spectral manipulation of light through a materials structure, and the development of a printing technology for scalable and precise placement of single quantum light sources, such as a single fluorescent molecule.
In an optical imaging system, the resolution is determined by the maximum angle of deflection/acceptance that the imaging objective provides and the refractive index of the surrounding medium. While over decades, the processes of lens making have improved to provide high-end refractive optical elements such as conventional bulky microscope objective lenses, implementing the same resolution, and thus the large deflection angles, in flat optical components is not straightforward. Here, we present a method for designing optical metasurfaces, that enables the efficient deflection of light at large angles and thus realizing flat lenses for imaging objects with subwavelength resolution. The experimentally demonstrated flat lenses show diffraction-limited resolution down to one third of the wavelength of light in the visible spectral range. These demonstrated achievements are particularly promising as they set the groundwork for the realization of flat optical components for imaging, beam focusing, beam shaping and holography with high resolution. Another essential characteristic of light with profound implications for everyday life is the spectral distribution of light intensity, giving rise to the human perception of colors in the visible spectral range. Here, nanophotonics provides a promising pathway to generate long-lasting, vivid structural colors with diffraction-limited resolution. One largely overlooked problem in the nanophotonic generation of colors is the variation of color brightness and color mixing, which is necessary for the photo-accurate representation of images. Here, we propose a plasmonic multi-color pixel that allows for mixing the three primary color components, red,green and blue, and individually and continuously setting their brightness. With this, we demonstrate the continuous coverage of a color gamut representing up to 39% of the standard sRGB color gamut, and the representation of photo-accurate color and grayscale images. The high achieved level of control over color brightness, chromaticity and mixing enables the realization of countless number of colors and is promising for applications such as anti-counterfeiting security features and miniaturized displays.
Finally, an important problem for controlling light in the quantum regime is tailoring the interaction of a quantum light source with its environment. Optimizing this interaction can lead to a brighter and faster emission, and an efficient collection of light from the source, or it can produce intriguing mixed states of light-matter coupling. The control over this interaction however requires a precise control of the emitter’s position and orientation with respect to the environment. While many studies have relied on a stochastic placement of emitters with respect to an ordered environment, more controlled and scalable methods for the precise nanopositioning of quantum emitters are needed. Here, we demonstrate the controlled and high-yield deposition of single fluorescent molecules with ± 100 nm accuracy and a well-defined orientation using electrohydrodynamic nanoprinting. The quantum emitters, in our case single dye molecules, are deposited with high yield and provide photostable fluorescence emission. Furthermore, our method allows for scalable and controlled coupling of single quantum emitters to a nanophotonic environment, as experimentally demonstrated on the example of coupling to photonic and plasmonic waveguides. Due to several orders of magnitudes higher success rates of nanopositioning, our method enables a new set of fundamental experiments on light-matter interaction and may also enable industrially relevant applications such as the high-yield fabrication of fiber-coupled single photon sources.ETH Bibliographie
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