Nils Nüsse

Enhancement of the zero phonon line emission from a single nitrogen vacancy center in a nanodiamond via coupling to a photonic crystal cavity

Using a nanomanipulation technique a nanodiamond with a single nitrogen vacancy center is placed directly on the surface of a gallium phosphide photonic crystal cavity. A Purcell-enhancement of the fluorescence emission at the zero phonon line (ZPL) by a factor of 12.1 is observed. The ZPL coupling is a first crucial step toward future diamond-based integrated quantum optical devices.

Nanoassembled Plasmonic-Photonic Hybrid Cavity for Tailored Light-Matter Coupling

We propose and demonstrate a hybrid cavity system in which metal nanoparticles are evanescently coupled to a dielectric photonic crystal cavity using a nanoassembly method. While the metal constituents lead to strongly localized fields, optical feedback is provided by the surrounding photonic crystal structure. The combined effect of plasmonic field enhancement and high quality factor (Q approximately 900) opens new routes for the control of light-matter interaction at the nanoscale.

Controlled coupling of a single-diamond nanocrystal to a photonic crystal cavity

We demonstrate the controlled coupling of a single diamond nanocrystal to a planar photonic crystal double-heterostructure cavity. A dip-pen deposition method and subsequent manipulation with an atomic force microscope was used to precisely position the nanocrystal on top of the cavity. The optical properties of this combined system are investigated with regard to changes in the quality factor and resonance wavelength of the cavity mode as a function of the size and relative position of the diamond nanocrystal. These studies represent an important step toward well-controlled cavity-QED experiments with single-defect centers in diamond.

Emission properties of high-Q silicon nitride photonic crystal heterostructure cavities

We report on the fabrication and optical characterization of photonic crystal (PC) double-heterostructure cavities made from silicon nitride (SiN). The intrinsic luminescence of the SiN membranes was used as an internal light source in the visible wavelength range (600–700nm) to study the quality factor and polarization properties of the cavity modes. Quality factors of up to 3400 were found experimentally, which represents the highest value reported so far in low-index PCs. These results highlight the role of SiN as a promising material system for PC devices in the visible.

Assembly of fundamental photonic elements from single nanodiamonds

We demonstrate the ability to modify the emission properties and enhance the interaction strength of single emitters coupled to nanophotonic structures based on metals and dielectrics. Assembly of individual diamond nanocrystals, metal nanoparticles and photonic crystal cavities to meta-structures is introduced. Experiments concerning controlled coupling of single defect centers in nanodiamonds to silver nanowires with the goal to investigate quantum plasmonic effects are reported. Furthermore, we demonstrate the formation of a hybrid cavity system in which metal nanostructures are evanescently coupled to a dielectric photonic crystal cavity. This structure allows combined exploitation of both resonant dielectric as well as plasmonic enhancement.

Plasmonic-photonic hybrid cavity for tailored light-matter coupling

We propose and demonstrate a hybrid cavity system in which metal nanoparticles are evanescently coupled to a dielectric photonic crystal cavity using a nanoassembly method. While the metal constituents lead to strongly localized fields, optical feedback is provided by the surrounding photonic crystal structure. The combined effect of plasmonic field enhancement and high quality factor (Q ≈ 900) opens new routes for the control of light-matter interaction at the nanoscale.

Hybrid approaches toward single emitter coupling to optical microresonators

We introduce a novel approach to assemble fundamental nanophotonic model systems. The approach is based on the controlled manipulation of single quantum emitters (defect centers in diamond) via scanning probes. We demonstrate coupling of a single diamond nanocrystal to a planar photonic crystal double-heterostructure cavity as well as to a silica toroidal resonator. Our studies represent an important step towards well-controlled cavity-QED experiments with single defect centers in diamond.

Fabrication and characterization of photonic crystal cavities in the visible range

We report on the fabrication and optical characterization of photonic crystal cavities for visible wavelengths made from silicon nitride (SiN). We note significant improvements in fabrication process with respect to our previous studies. The intrinsic luminescence of the SiN membranes was used as an internal light source to study the quality factor of the cavity modes. We experimentally found values as high as 3400, which are up to the present unsurpassed for photonic crystal resonators in the visible spectra range. Finite difference time domain (FDTD) simulations suggest another boost by a factor of two is possible by further optimizing the fabrication process. We describe a method by which arbitrary emitters or other nanoscopic objects can be coupled in a deterministic way by using the manipulation capabilities of an atomic force microscope.

Controlled coupling of nanoparticles to photonic crystal cavities

We demonstrate a hybrid approach for the realization of novel nanophotonic devices by combining lithographic fabrication techniques with a nano-manipulation method. In particular, we report on the fabrication of photonic crystal cavities as a platform to which arbitrary emitters or other nanoscopic objects can be coupled in a deterministic way by exploiting the manipulation capabilities of an atomic force microscope. In addition, the optical properties of such particle-cavity systems are analyzed with regard to changes of the quality factor and resonance wavelength of the cavity mode. Our approach is well suited to create improved single photon sources and also complex photonic devices with several emitters coupled coherently via shared cavity modes.