Nanoelectromechanical control of spin-photon interfaces in a hybrid quantum system on chip

Atom-like defects or color centers (CC's) in nanostructured diamond are a leading platform for optically linked quantum technologies, with recent advances including memory-enhanced quantum communication, multi-node quantum networks, and spin-mediated generation of photonic cluster states. Scaling to practically useful applications motivates architectures meeting the following criteria: C1 individual optical addressing of spin qubits; C2 frequency tuning of CC spin-dependent optical transitions; C3 coherent spin control in CC ground states; C4 active photon routing; C5 scalable manufacturability; and C6 low on-chip power dissipation for cryogenic operations. However, no architecture meeting C1-C6 has thus far been demonstrated. Here, we introduce a hybrid quantum system-on-chip (HQ-SoC) architecture that simultaneously achieves C1-C6. Key to this advance is the realization of piezoelectric strain control of diamond waveguide-coupled tin vacancy centers to meet C2 and C3, with ultra-low power dissipation necessary for C6. The DC response of our device allows emitter transition tuning by over 20 GHz, while the large frequency range (exceeding 2 GHz) enables low-power AC control. We show acoustic manipulation of integrated tin vacancy spins and estimate single-phonon coupling rates over 1 kHz in the resolved sideband regime. Combined with high-speed optical routing with negligible static hold power, this HQ-SoC platform opens the path to scalable single-qubit control with optically mediated entangling gates

Hybrid Laser-Etching-Process for Wafer Texturing

AbstractAn approach of a texturing process combining surface modification by ultra-short pulsed laser radiation and etching techniques is developed. The hybrid process is divided into two steps: Firstly, the surface of a silicon wafer is modified by laser radiation. For this purpose, the influence of several laser parameters, e.g. wavelength, pulse duration and energy density, have been analyzed. Secondly, the surface texture is fabricated by an etching process.The modification threshold of the laser treatment is determined for different silicon materials. Different surface modifications occur for different materials after applying the laser treatment. No significant influence of the pulse duration or focus radius is found.Furthermore, the influence of laser processing and plasma etching on reflectivity spectra is compared and interactions between laser and etching parameters are investigated. The developed hybrid process results in smooth and fine surface microstructures. First results show a reduction of the reflectivity in the range of 30% compared to the reflectivity of unstructured wafers

Influence of pulse duration in picosecond laser ablation of silicon nitride layers

AbstractLasers as production tools offer several advantages, which are especially relevant for the production of solar cells. The contact-less and localized nature of the energy deposition allows new processes, such as laser selective emitter doping, laser ablation of dielectric coatings and via drilling for back contact cell concepts. A highly critical factor is the correct selection of laser parameters and thus laser sources in a manner that adapts the laser process to the requirements of the material, the process nature and the solar cell properties. In this paper the influence of the pulse duration in the range from hundreds of femtoseconds to ten picoseconds on the selective ablation of silicon nitride from multi-crytsalline solar cells is investigated. For this process it is critical to avoid damage to the sensitive emitter and ultra-short laser sources have the potential to enable this process

Picosecond laser ablation for silicon micro fuel cell fabrication

We have investigated laser ablation as a microfabrication approach to produce micro fuel cells (MFCs) in silicon. Picosecond pulses (15 ps) at a wavelength of 355 nm are used to make all of the MFC structures. To assess the benefits and drawbacks of laser ablation, reference cells have been produced by deep reactive ion etching (DRIE) using matching geometries. Ablated and etched cells have been evaluated and compared side by side. Our conclusion is that picosecond laser ablation is very well suited for MFC fabrication. The ablated cells match or excel DRIE-microfabricated cells in terms of current and power densities. Ablated MFCs achieved 47.6 mW cm-2 of power density and 121 mA cm-2 current density.Peer reviewe