Mark P. Hiscocks

Diamond waveguides fabricated by reactive ion etching

We demonstrate for the first time the feasibility of all-diamond integrated optic devices over large areas using a combination of photolithography, reactive ion etching (RIE) and focused ion beam (FIB) techniques. We confirm the viability of this scalable process by demonstrating guidance in a two-moded ridge waveguide in type 1b single crystal diamond. This opens the door to the fabrication of a diamond-based optical chip integrating functional elements such as X-crossings, Y-junctions, evanescent couplers, Bragg reflectors/couplers and various interferometers.

Diamond-based structures to collect and guide light

We examine some promising photonic structures for collecting and guiding light in bulk diamond. The aim of this work is to optimize single photon sources and single spin read-out from diamond color centers, specifically NV centers. We review the modeling and fabrication (by focused ion beam and reactive ion etching) of solid immersion lenses, waveguides and photonic crystal cavities in monolithic diamond.

Slot-waveguide cavities for optical quantum information applications

To take existing quantum optical experiments and devices into a more practical regimes requires the construction of robust, solid-state implementations. In particular, to observe the strong-coupling regime of tom-photon interactions requires very small cavities and large quality factors. Here we show that the slot-waveguide geometry recently introduced for photonic applications is also promising for quantum optical applications in the visible regime. We study diamond- and GaP-based slot-waveguide cavities (SWCs) compatible with diamond colour centres e.g. nitrogen-vacancy (NV) defect. We show that one can achieve increased single-photon Rabi frequencies of order O(10(11)) rad s(-1) in ultra-small cavity modal volumes, nearly 2 orders of magnitude smaller than previously studied diamond-based photonic crystal cavities.

Accessing diamond waveguides and future applications

Recent advances in the production of high-purity synthetic diamonds have made diamond an accessible host material for applications in present and future optoelectronic and photonic devices. We have developed a scalable process for fabricating photonic devices in diamond using reactive ion etching (RIE) and photolithography as well as using ion implantation to provide vertical confinement. Applying this we have demonstrated a few-moded waveguide with a large cross section for easier coupling to optical fibre. We present our work towards in-plane coupling to diamond waveguides and consequently characterisation of these waveguides. We also examine the application of diamond waveguides to other photonic applications for achieving light confinement in a subwavelength cavity site using a slot-waveguide design. Such cavities may be used to enhance photon-emission properties of a built-in diamond colour centre and to achieve strong light-matter interactions on the single-quantum level necessary for quantum information technology. Using single cavities as building block, we also show that these structures can be suitably coupled to form one-dimensional coupled-resonator array.

Coupling slot-waveguide cavities for large-scale quantum optical devices

By offering effective modal volumes significantly less than a cubic wavelength, slot-waveguide cavities offer a new in-road into strong atom-photon coupling in the visible regime. Here we explore two-dimensional arrays of coupled slot cavities which underpin designs for novel quantum emulators and polaritonic quantum phase transition devices. Specifically, we investigate the lateral coupling characteristics of diamond-air and GaP-air slot waveguides using numerically-assisted coupled-mode theory, and the longitudinal coupling properties via distributed Bragg reflectors using mode-propagation simulations. We find that slot-waveguide cavities in the Fabry-Perot arrangement can be coupled and effectively treated with a tight-binding description, and are a suitable platform for realizing Jaynes-Cummings-Hubbard physics.

Fabricating novel diamond waveguides using the focused ion beam hard mask

The Focused ion beam has been used to direct write a hard mask against the plasma etching of diamond. Nano-waveguides were fabricated from diamond-on-silica thin films close to ideal dimensions predicted via FIMMWAVE simulations.

Processing of Diamond: Towards All-Diamond Integrated Optics

Diamond photonic devices present a range of opportunities due to their unique properties. This paper presents progress in the fabrication of diamond waveguides using reactive ion etching (RIE), as a step towards all-diamond optics.

Progress towards achieving diamond waveguides

We report on the progress made towards achieving light guidance in long diamond waveguides (i.e. > mm) fabricated using a combination of photolithography, reactive ion etching (RIE), ion implantation and FIB techniques.