The potential of diamond as an optical material for high-power laser applications in the wavelength regime from the visible spectrum (VIS) to the near infrared (NIR) is investigated. Single-crystal diamonds with lateral dimensions up to 7×7mm2 are grown with microwave plasma assisted chemical vapor deposition (MPACVD) in parallel with up to 60 substrates and are further processed to spherical optics for beam guidance and shaping. The synthetic diamonds offer superior thermal, mechanical and optical properties, including low birefringence, scattering and absorption, also around 1 μm wavelength. We present dielectric (AR and HR) coated single-crystal diamond optics which are tested under high laser power in the multi-kW regime. The thermally induced focal shift of the diamond substrates is compared to the focal shift of a standard collimating and focusing unit for laser cutting made of fused silica optics. Due to the high thermal conductivity and low absorption of the diamond substrates compared to the fused silica optics no additional focal shift caused by a thermally induced refractive index change in the diamond is observed in our experiments. We present experimental results regarding the performance of the diamond substrates with and without dielectric coatings under high power and the influences of growth induced birefringence on the optical quality. Finally, we discuss the potential of the presented diamond lenses for high-power applications in the field of laser materials processing.

The silicon vacancy center (SiV) in diamond is promising for future quantum applications due to its unique properties like narrowband emission in the near infrared regime at 738 nm and photostability at room temperature. In this paper we investigate the photoluminescence and electroluminescence properties of SiV centers incorporated into the intrinsic-layer of single crystalline diamond p–i–n junction diodes via in-situ doping during CVD-growth. The experiments reveal electrical excitation of the SiV emission by applying forward currents. The electroluminescence and photoluminescence properties are compared and discussed.

Nanophotonic circuits based on polished diamond thin films are prepared. These circuits cover a wide wavelength range across the entire visible spectrum. Integrated devices are surface functionalized site-specifically and in parallel using dip-pen nanolithography with a minimum linewidth of 100 nm. Multicolor fluorescence is coupled into the underlying photonic network using microring resonators and grating structures.

Single crystalline diamond nanowires of different sizes and shapes were fabricated with electron beam lithography and inductively coupled plasma etching using oxygen. Titanium and chromium have been used as etching mask, where titanium appeared to be more chemically resistant. We were able to fabricate nanowires from 60nm diameter to 200nm with a length of approximately 1μm. As the nanowire should be used in the future as a waveguide for the NV fluorescence originating from the apex of the structure, simulations were done with Comsol Multiphysics in order to determine the dependency between shape and guidance properties.

We realize diamond electro-optomechanical resonators operated at frequencies above 100 MHz. The nanomechanical motion is read-out via on-chip diamond photonic circuits showing Q-factors above 1300.

Photonic quantum technologies hold promise to repeat the success of integrated nanophotonic circuits in non-classical applications. Using linear optical elements, quantum optical computations can be performed with integrated optical circuits and can therefore overcome the existing limitations in terms of scalability. In addition to passive optical devices for realizing photonic quantum gates, active elements, such as single-photon sources and single-photon detectors, are essential ingredients for future optical quantum circuits. Material systems that allow for the monolithic integration of all components are particularly attractive, including III-V semiconductors, silicon and diamond. Here, we demonstrate nanophotonic integrated circuits made from high-quality polycrystalline diamond thin films in combination with on-chip single-photon detectors. By using superconducting nanowires that are coupled evanescently to traveling waves, we achieve high detection efficiencies of up to 66% as well as low dark count rates and a timing resolution of 190 ps. Our devices are fully scalable and hold promise for functional diamond photonic quantum devices.

We demonstrate integrated optomechanical circuits with high mechanical quality factors prepared from nanocrystalline diamond thin films. Using chemomechanical polishing, the RMS surface roughness of as grown polycrystalline diamond films is reduced below 3 nm to allow for the fabrication of high-quality nanophotonic circuits. By integrating free-standing nanomechanical resonators into integrated optical devices, efficient read-out of the thermomechanical motion of diamond resonators is achieved with on-chip Mach–Zehnder interferometers. Mechanical quality factors up to 28,800 are measured for four-fold clamped optomechanical resonators coupled to the evanescent near-field of nanophotonic waveguides. Our platform holds promise for large-scale integration of optomechanical circuits for on-chip metrology and sensing applications.

This letter describes the procedure to manufacture high-performance surface acoustic wave (SAW) resonators on AlN/diamond heterostructures working at frequencies beyond 10 GHz. In the design of SAW devices on AlN/diamond systems, the thickness of the piezoelectric layer is a key parameter. The influence of the film thickness on the SAW device response has been studied. Optimized thin films combined with advanced e-beam lithographic techniques have allowed the fabrication of one-port SAW resonators with finger width and pitch of 200 nm operating in the 10-14 GHz range with up to 36 dB out-of-band rejection.