arXiv subjects

F. Koppens

Publications and source records attributed to F. Koppens.

3 recordsLinked to original sources

arXiv2019

Electrical control of lifetime-limited quantum emitters using 2D materials

Solid state quantum emitters are a mainstay of quantum nanophotonics as integrated single photon sources (SPS) and optical nanoprobes. Integrating such emitters with active nanophotonic elements is desirable in order to attain efficient control of their optical properties but typically degrades the photostability of the emitter itself. Here, we demonstrate a tuneable hybrid device that integrates lifetime-limited single emitters (linewidth : 40 MHz) and 2D materials at sub-wavelength separation without degradation of the emission properties. Our device s nanoscale dimensions enable ultra-broadband tuning (tuning range larger than 400 GHz) and fast modulation (frequency : 100 MHz) of the emission energy, which renders it an integrated, ultra-compact tuneable SPS. Conversely, this offers a novel approach to optical sensing of 2D material properties using a single emitter as a nanoprobe.

cond-mat.mes-hall↗

arXiv2018

THz nanofocusing with cantilevered THz-resonant antenna tips

We developed THz-resonant scanning probe tips, yielding strongly enhanced and nanoscale confined THz near fields at their tip apex. The tips with length in the order of the THz wavelength (λ = 96.5 μm) were fabricated by focused ion beam (FIB) machining and attached to standard atomic force microscopy (AFM) cantilevers. Measurements of the near-field intensity at the very tip apex (25 nm radius) as a function of tip length, via graphene-based (thermoelectric) near-field detection, indicate their first and second order geometrical antenna resonances for tip length of 33 and 78 μm, respectively. On resonance, we find that the near-field intensity is enhanced by one order of magnitude compared to tips of 17 μm length (standard AFM tip length), which is corroborated by numerical simulations that further predict remarkable intensity enhancements of about 107 relative to the incident field. Because of the strong field enhancement and standard AFM operation of our tips, we envision manifold and straightforward future application in scattering-type THz near-field nanoscopy and THz photocurrent nanoimaging, nanoscale nonlinear THz imaging, or nanoscale control and manipulation of matter employing ultrastrong and ultrashort THz pulses.

physics.optics↗

arXiv2014

Single-molecule study for a graphene-based nano-position sensor

In this study we lay the groundwork for a graphene-based fundamental ruler at the nanoscale. It relies on the efficient energy-transfer mechanism between single quantum emitters and low-doped graphene monolayers. Our experiments, conducted with dibenzoterrylene (DBT) molecules, allow going beyond ensemble analysis due to the emitter photo-stability and brightness. A quantitative characterization of the fluorescence decay-rate modification is presented and compared to a simple model, showing agreement with the $d^{-4}$ dependence, a genuine manifestation of a dipole interacting with a 2D material. With DBT molecules, we can estimate a potential uncertainty in position measurements as low as 5nm in the range below 30nm.

cond-mat.mes-hall↗